Added SegmentFruit

CHANGELOG.md

@@ -1,4 +1,4 @@
-Tantivy 0.8.0
+Tantivy 0.8.1
 =====================
 *No change in the index format*
 - API Breaking change in the collector API. (@jwolfe, @fulmicoton)

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tantivy"
-version = "0.8.2"
+version = "0.8.0-dev"
 authors = ["Paul Masurel <paul.masurel@gmail.com>"]
 license = "MIT"
 categories = ["database-implementations", "data-structures"]
@@ -29,7 +29,7 @@ serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
 num_cpus = "1.2"
-itertools = "0.8"
+itertools = "0.7"
 levenshtein_automata = {version="0.1", features=["fst_automaton"]}
 bit-set = "0.5"
 uuid = { version = "0.7", features = ["v4", "serde"] }
@@ -49,7 +49,6 @@ failure = "0.1"
 htmlescape = "0.3.1"
 fail = "0.2"
 scoped-pool = "1.0"
-murmurhash32 = "0.2"
 
 [target.'cfg(windows)'.dependencies]
 winapi = "0.2"

examples/custom_collector.rs

@@ -70,6 +70,8 @@ impl Collector for StatsCollector {
     // Our standard deviation will be a float.
     type Fruit = Option<Stats>;
 
+    type SegmentFruit = Self::Fruit;
+
     type Child = StatsSegmentCollector;
 
     fn for_segment(

src/collector/count_collector.rs

@@ -58,6 +58,7 @@ pub struct Count;
 
 impl Collector for Count {
     type Fruit = usize;
+    type SegmentFruit = usize;
 
     type Child = SegmentCountCollector;
 

src/collector/facet_collector.rs

@@ -197,7 +197,7 @@ fn skip<'a, I: Iterator<Item = &'a Facet>>(
 ) -> SkipResult {
     loop {
         match collapse_it.peek() {
-            Some(facet_bytes) => match facet_bytes.encoded_str().as_bytes().cmp(target) {
+            Some(facet_bytes) => match facet_bytes.encoded_bytes().cmp(target) {
                 Ordering::Less => {}
                 Ordering::Greater => {
                     return SkipResult::OverStep;
@@ -258,6 +258,8 @@ impl FacetCollector {
 impl Collector for FacetCollector {
     type Fruit = FacetCounts;
 
+    type SegmentFruit = FacetCounts;
+
     type Child = FacetSegmentCollector;
 
     fn for_segment(
@@ -369,8 +371,7 @@ impl SegmentCollector for FacetSegmentCollector {
             let mut facet = vec![];
             let facet_ord = self.collapse_facet_ords[collapsed_facet_ord];
             facet_dict.ord_to_term(facet_ord as u64, &mut facet);
-            // TODO
-            facet_counts.insert(Facet::from_encoded(facet).unwrap(), count);
+            facet_counts.insert(unsafe { Facet::from_encoded(facet) }, count);
         }
         FacetCounts { facet_counts }
     }
@@ -404,9 +405,9 @@ impl FacetCounts {
         let right_bound = if facet.is_root() {
             Bound::Unbounded
         } else {
-            let mut facet_after_bytes: String = facet.encoded_str().to_owned();
-            facet_after_bytes.push('\u{1}');
-            let facet_after = Facet::from_encoded_string(facet_after_bytes);
+            let mut facet_after_bytes: Vec<u8> = facet.encoded_bytes().to_owned();
+            facet_after_bytes.push(1u8);
+            let facet_after = unsafe { Facet::from_encoded(facet_after_bytes) }; // ok logic
             Bound::Excluded(facet_after)
         };
         let underlying: btree_map::Range<_, _> = self.facet_counts.range((left_bound, right_bound));

src/collector/mod.rs

@@ -136,8 +136,10 @@ pub trait Collector: Sync {
     /// e.g. `usize` for the `Count` collector.
     type Fruit: Fruit;
 
+    type SegmentFruit: Fruit;
+
     /// Type of the `SegmentCollector` associated to this collector.
-    type Child: SegmentCollector<Fruit = Self::Fruit>;
+    type Child: SegmentCollector<Fruit = Self::SegmentFruit>;
 
     /// `set_segment` is called before beginning to enumerate
     /// on this segment.
@@ -152,7 +154,7 @@ pub trait Collector: Sync {
 
     /// Combines the fruit associated to the collection of each segments
     /// into one fruit.
-    fn merge_fruits(&self, segment_fruits: Vec<Self::Fruit>) -> Result<Self::Fruit>;
+    fn merge_fruits(&self, segment_fruits: Vec<Self::SegmentFruit>) -> Result<Self::Fruit>;
 }
 
 /// The `SegmentCollector` is the trait in charge of defining the
@@ -181,6 +183,9 @@ where
     Right: Collector,
 {
     type Fruit = (Left::Fruit, Right::Fruit);
+
+    type SegmentFruit = (Left::SegmentFruit, Right::SegmentFruit);
+
     type Child = (Left::Child, Right::Child);
 
     fn for_segment(&self, segment_local_id: u32, segment: &SegmentReader) -> Result<Self::Child> {
@@ -195,7 +200,7 @@ where
 
     fn merge_fruits(
         &self,
-        children: Vec<(Left::Fruit, Right::Fruit)>,
+        children: Vec<(Left::SegmentFruit, Right::SegmentFruit)>,
     ) -> Result<(Left::Fruit, Right::Fruit)> {
         let mut left_fruits = vec![];
         let mut right_fruits = vec![];
@@ -236,6 +241,7 @@ where
     Three: Collector,
 {
     type Fruit = (One::Fruit, Two::Fruit, Three::Fruit);
+    type SegmentFruit = (One::SegmentFruit, Two::SegmentFruit, Three::SegmentFruit);
     type Child = (One::Child, Two::Child, Three::Child);
 
     fn for_segment(&self, segment_local_id: u32, segment: &SegmentReader) -> Result<Self::Child> {
@@ -249,7 +255,7 @@ where
         self.0.requires_scoring() || self.1.requires_scoring() || self.2.requires_scoring()
     }
 
-    fn merge_fruits(&self, children: Vec<Self::Fruit>) -> Result<Self::Fruit> {
+    fn merge_fruits(&self, children: Vec<Self::SegmentFruit>) -> Result<Self::Fruit> {
         let mut one_fruits = vec![];
         let mut two_fruits = vec![];
         let mut three_fruits = vec![];
@@ -295,6 +301,7 @@ where
     Four: Collector,
 {
     type Fruit = (One::Fruit, Two::Fruit, Three::Fruit, Four::Fruit);
+    type SegmentFruit = (One::SegmentFruit, Two::SegmentFruit, Three::SegmentFruit, Four::SegmentFruit);
     type Child = (One::Child, Two::Child, Three::Child, Four::Child);
 
     fn for_segment(&self, segment_local_id: u32, segment: &SegmentReader) -> Result<Self::Child> {
@@ -312,7 +319,7 @@ where
             || self.3.requires_scoring()
     }
 
-    fn merge_fruits(&self, children: Vec<Self::Fruit>) -> Result<Self::Fruit> {
+    fn merge_fruits(&self, children: Vec<Self::SegmentFruit>) -> Result<Self::Fruit> {
         let mut one_fruits = vec![];
         let mut two_fruits = vec![];
         let mut three_fruits = vec![];

src/collector/multi_collector.rs

@@ -18,6 +18,7 @@ pub struct CollectorWrapper<TCollector: Collector>(TCollector);
 
 impl<TCollector: Collector> Collector for CollectorWrapper<TCollector> {
     type Fruit = Box<Fruit>;
+    type SegmentFruit = Box<Fruit>;
     type Child = Box<BoxableSegmentCollector>;
 
     fn for_segment(
@@ -34,10 +35,10 @@ impl<TCollector: Collector> Collector for CollectorWrapper<TCollector> {
     }
 
     fn merge_fruits(&self, children: Vec<<Self as Collector>::Fruit>) -> Result<Box<Fruit>> {
-        let typed_fruit: Vec<TCollector::Fruit> = children
+        let typed_fruit: Vec<TCollector::SegmentFruit> = children
             .into_iter()
             .map(|untyped_fruit| {
-                Downcast::<TCollector::Fruit>::downcast(untyped_fruit)
+                Downcast::<TCollector::SegmentFruit>::downcast(untyped_fruit)
                     .map(|boxed_but_typed| *boxed_but_typed)
                     .map_err(|e| {
                         let err_msg = format!("Failed to cast child collector fruit. {:?}", e);
@@ -152,7 +153,7 @@ impl<TFruit: Fruit> FruitHandle<TFruit> {
 #[derive(Default)]
 pub struct MultiCollector<'a> {
     collector_wrappers:
-        Vec<Box<Collector<Child = Box<BoxableSegmentCollector>, Fruit = Box<Fruit>> + 'a>>,
+        Vec<Box<Collector<Child = Box<BoxableSegmentCollector>, Fruit = Box<Fruit>, SegmentFruit = Box<Fruit>> + 'a>>,
 }
 
 impl<'a> MultiCollector<'a> {
@@ -177,7 +178,9 @@ impl<'a> MultiCollector<'a> {
 }
 
 impl<'a> Collector for MultiCollector<'a> {
+
     type Fruit = MultiFruit;
+    type SegmentFruit = MultiFruit;
     type Child = MultiCollectorChild;
 
     fn for_segment(

src/collector/tests.rs

@@ -40,6 +40,7 @@ impl TestFruit {
 
 impl Collector for TestCollector {
     type Fruit = TestFruit;
+    type SegmentFruit = Self::Fruit;
     type Child = TestSegmentCollector;
 
     fn for_segment(
@@ -109,6 +110,8 @@ impl FastFieldTestCollector {
 
 impl Collector for FastFieldTestCollector {
     type Fruit = Vec<u64>;
+    type SegmentFruit = Self::Fruit;
+
     type Child = FastFieldSegmentCollector;
 
     fn for_segment(
@@ -165,6 +168,7 @@ impl BytesFastFieldTestCollector {
 
 impl Collector for BytesFastFieldTestCollector {
     type Fruit = Vec<u8>;
+    type SegmentFruit = Self::Fruit;
     type Child = BytesFastFieldSegmentCollector;
 
     fn for_segment(

src/collector/top_field_collector.rs

@@ -88,6 +88,7 @@ impl<T: FastValue + PartialOrd + Clone> TopDocsByField<T> {
 
 impl<T: FastValue + PartialOrd + Send + Sync + 'static> Collector for TopDocsByField<T> {
     type Fruit = Vec<(T, DocAddress)>;
+    type SegmentFruit = Vec<(T, DocAddress)>;
 
     type Child = TopFieldSegmentCollector<T>;
 

src/collector/top_score_collector.rs

@@ -89,6 +89,7 @@ impl TopDocs {
 
 impl Collector for TopDocs {
     type Fruit = Vec<(Score, DocAddress)>;
+    type SegmentFruit = Vec<(Score, DocAddress)>;
 
     type Child = TopScoreSegmentCollector;
 

src/common/bitpacker.rs

@@ -1,6 +1,9 @@
-use byteorder::{ByteOrder, LittleEndian, WriteBytesExt};
+use common::serialize::BinarySerializable;
 use std::io;
+use std::io::Write;
+use std::mem;
 use std::ops::Deref;
+use std::ptr;
 
 pub(crate) struct BitPacker {
     mini_buffer: u64,
@@ -15,7 +18,7 @@ impl BitPacker {
         }
     }
 
-    pub fn write<TWrite: io::Write>(
+    pub fn write<TWrite: Write>(
         &mut self,
         val: u64,
         num_bits: u8,
@@ -25,14 +28,14 @@ impl BitPacker {
         let num_bits = num_bits as usize;
         if self.mini_buffer_written + num_bits > 64 {
             self.mini_buffer |= val_u64.wrapping_shl(self.mini_buffer_written as u32);
-            output.write_u64::<LittleEndian>(self.mini_buffer)?;
+            self.mini_buffer.serialize(output)?;
             self.mini_buffer = val_u64.wrapping_shr((64 - self.mini_buffer_written) as u32);
             self.mini_buffer_written = self.mini_buffer_written + num_bits - 64;
         } else {
             self.mini_buffer |= val_u64 << self.mini_buffer_written;
             self.mini_buffer_written += num_bits;
             if self.mini_buffer_written == 64 {
-                output.write_u64::<LittleEndian>(self.mini_buffer)?;
+                self.mini_buffer.serialize(output)?;
                 self.mini_buffer_written = 0;
                 self.mini_buffer = 0u64;
             }
@@ -40,18 +43,17 @@ impl BitPacker {
         Ok(())
     }
 
-    pub fn flush<TWrite: io::Write>(&mut self, output: &mut TWrite) -> io::Result<()> {
+    pub fn flush<TWrite: Write>(&mut self, output: &mut TWrite) -> io::Result<()> {
         if self.mini_buffer_written > 0 {
             let num_bytes = (self.mini_buffer_written + 7) / 8;
-            let mut arr: [u8; 8] = [0u8; 8];
-            LittleEndian::write_u64(&mut arr, self.mini_buffer);
+            let arr: [u8; 8] = unsafe { mem::transmute::<u64, [u8; 8]>(self.mini_buffer.to_le()) };
             output.write_all(&arr[..num_bytes])?;
             self.mini_buffer_written = 0;
         }
         Ok(())
     }
 
-    pub fn close<TWrite: io::Write>(&mut self, output: &mut TWrite) -> io::Result<()> {
+    pub fn close<TWrite: Write>(&mut self, output: &mut TWrite) -> io::Result<()> {
         self.flush(output)?;
         // Padding the write file to simplify reads.
         output.write_all(&[0u8; 7])?;
@@ -100,7 +102,9 @@ where
             addr + 8 <= data.len(),
             "The fast field field should have been padded with 7 bytes."
         );
-        let val_unshifted_unmasked: u64 = LittleEndian::read_u64(&data[addr..]);
+        #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+        let val_unshifted_unmasked: u64 =
+            u64::from_le(unsafe { ptr::read_unaligned(data[addr..].as_ptr() as *const u64) });
         let val_shifted = (val_unshifted_unmasked >> bit_shift) as u64;
         val_shifted & mask
     }
@@ -122,7 +126,9 @@ where
             for output_val in output.iter_mut() {
                 let addr = addr_in_bits >> 3;
                 let bit_shift = addr_in_bits & 7;
-                let val_unshifted_unmasked: u64 = LittleEndian::read_u64(&data[addr..]);
+                #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+                let val_unshifted_unmasked: u64 =
+                    unsafe { ptr::read_unaligned(data[addr..].as_ptr() as *const u64) };
                 let val_shifted = (val_unshifted_unmasked >> bit_shift) as u64;
                 *output_val = val_shifted & mask;
                 addr_in_bits += num_bits;

src/core/executor.rs

@@ -64,18 +64,17 @@ impl Executor {
                     // This is important as it makes it possible for the fruit_receiver iteration to
                     // terminate.
                 };
-                // This is lame, but it does not use unsafe code.
-                let mut results_with_position = Vec::with_capacity(num_fruits);
+                let mut results = Vec::with_capacity(num_fruits);
+                unsafe { results.set_len(num_fruits) };
+                let mut num_items = 0;
                 for (pos, fruit_res) in fruit_receiver {
-                    let fruit = fruit_res?;
-                    results_with_position.push((pos, fruit));
+                    results[pos] = fruit_res?;
+                    num_items += 1;
                 }
-                results_with_position.sort_by_key(|(pos, _)| *pos);
-                assert_eq!(results_with_position.len(), num_fruits);
-                Ok(results_with_position
-                    .into_iter()
-                    .map(|(_, fruit)| fruit)
-                    .collect::<Vec<_>>())
+                // this checks ensures that we filled of this
+                // uninitialized memory.
+                assert_eq!(num_items, results.len());
+                Ok(results)
             }
         }
     }

src/core/index.rs

@@ -13,7 +13,6 @@ use directory::ManagedDirectory;
 #[cfg(feature = "mmap")]
 use directory::MmapDirectory;
 use directory::{Directory, RAMDirectory};
-use error::DataCorruption;
 use error::TantivyError;
 use indexer::index_writer::open_index_writer;
 use indexer::index_writer::HEAP_SIZE_MIN;
@@ -38,13 +37,7 @@ fn load_metas(directory: &Directory) -> Result<IndexMeta> {
     let meta_data = directory.atomic_read(&META_FILEPATH)?;
     let meta_string = String::from_utf8_lossy(&meta_data);
     serde_json::from_str(&meta_string)
-        .map_err(|e| {
-            DataCorruption::new(
-                META_FILEPATH.clone(),
-                format!("Meta file cannot be deserialized. {:?}.", e),
-            )
-        })
-        .map_err(From::from)
+        .map_err(|_| TantivyError::CorruptedFile(META_FILEPATH.clone()))
 }
 
 /// Search Index
@@ -150,7 +143,7 @@ impl Index {
     ///
     /// This will overwrite existing meta.json
     fn from_directory(mut directory: ManagedDirectory, schema: Schema) -> Result<Index> {
-        save_new_metas(schema.clone(),  directory.borrow_mut())?;
+        save_new_metas(schema.clone(), 0, directory.borrow_mut())?;
         let metas = IndexMeta::with_schema(schema);
         Index::create_from_metas(directory, &metas)
     }

src/core/searcher.rs

@@ -23,7 +23,7 @@ fn collect_segment<C: Collector>(
     weight: &Weight,
     segment_ord: u32,
     segment_reader: &SegmentReader,
-) -> Result<C::Fruit> {
+) -> Result<C::SegmentFruit> {
     let mut scorer = weight.scorer(segment_reader)?;
     let mut segment_collector = collector.for_segment(segment_ord as u32, segment_reader)?;
     if let Some(delete_bitset) = segment_reader.delete_bitset() {

src/directory/managed_directory.rs

@@ -1,7 +1,7 @@
 use core::MANAGED_FILEPATH;
 use directory::error::{DeleteError, IOError, OpenReadError, OpenWriteError};
 use directory::{ReadOnlySource, WritePtr};
-use error::DataCorruption;
+use error::TantivyError;
 use indexer::LockType;
 use serde_json;
 use std::collections::HashSet;
@@ -64,12 +64,7 @@ impl ManagedDirectory {
             Ok(data) => {
                 let managed_files_json = String::from_utf8_lossy(&data);
                 let managed_files: HashSet<PathBuf> = serde_json::from_str(&managed_files_json)
-                    .map_err(|e| {
-                        DataCorruption::new(
-                            MANAGED_FILEPATH.clone(),
-                            format!("Managed file cannot be deserialized: {:?}. ", e),
-                        )
-                    })?;
+                    .map_err(|_| TantivyError::CorruptedFile(MANAGED_FILEPATH.clone()))?;
                 Ok(ManagedDirectory {
                     directory: Box::new(directory),
                     meta_informations: Arc::new(RwLock::new(MetaInformation {

src/error.rs

@@ -8,42 +8,9 @@ use indexer::LockType;
 use query;
 use schema;
 use serde_json;
-use std::fmt;
 use std::path::PathBuf;
 use std::sync::PoisonError;
 
-pub struct DataCorruption {
-    filepath: Option<PathBuf>,
-    comment: String,
-}
-
-impl DataCorruption {
-    pub fn new(filepath: PathBuf, comment: String) -> DataCorruption {
-        DataCorruption {
-            filepath: Some(filepath),
-            comment,
-        }
-    }
-
-    pub fn comment_only(comment: String) -> DataCorruption {
-        DataCorruption {
-            filepath: None,
-            comment,
-        }
-    }
-}
-
-impl fmt::Debug for DataCorruption {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        write!(f, "Data corruption: ")?;
-        if let Some(ref filepath) = &self.filepath {
-            write!(f, "(in file `{:?}`)", filepath)?;
-        }
-        write!(f, ": {}.", self.comment)?;
-        Ok(())
-    }
-}
-
 /// The library's failure based error enum
 #[derive(Debug, Fail)]
 pub enum TantivyError {
@@ -66,8 +33,8 @@ pub enum TantivyError {
     #[fail(display = "An IO error occurred: '{}'", _0)]
     IOError(#[cause] IOError),
     /// Data corruption.
-    #[fail(display = "{:?}", _0)]
-    DataCorruption(DataCorruption),
+    #[fail(display = "File contains corrupted data: '{:?}'", _0)]
+    CorruptedFile(PathBuf),
     /// A thread holding the locked panicked and poisoned the lock.
     #[fail(display = "A thread holding the locked panicked and poisoned the lock")]
     Poisoned,
@@ -88,12 +55,6 @@ pub enum TantivyError {
     SystemError(String),
 }
 
-impl From<DataCorruption> for TantivyError {
-    fn from(data_corruption: DataCorruption) -> TantivyError {
-        TantivyError::DataCorruption(data_corruption)
-    }
-}
-
 impl From<FastFieldNotAvailableError> for TantivyError {
     fn from(fastfield_error: FastFieldNotAvailableError) -> TantivyError {
         TantivyError::FastFieldError(fastfield_error)

src/fastfield/facet_reader.rs

@@ -1,6 +1,5 @@
 use super::MultiValueIntFastFieldReader;
 use schema::Facet;
-use std::str;
 use termdict::TermDictionary;
 use termdict::TermOrdinal;
 use DocId;
@@ -21,7 +20,6 @@ use DocId;
 pub struct FacetReader {
     term_ords: MultiValueIntFastFieldReader<u64>,
     term_dict: TermDictionary,
-    buffer: Vec<u8>,
 }
 
 impl FacetReader {
@@ -39,7 +37,6 @@ impl FacetReader {
         FacetReader {
             term_ords,
             term_dict,
-            buffer: vec![],
         }
     }
 
@@ -58,18 +55,11 @@ impl FacetReader {
     }
 
     /// Given a term ordinal returns the term associated to it.
-    pub fn facet_from_ord(
-        &mut self,
-        facet_ord: TermOrdinal,
-        output: &mut Facet,
-    ) -> Result<(), str::Utf8Error> {
+    pub fn facet_from_ord(&self, facet_ord: TermOrdinal, output: &mut Facet) {
         let found_term = self
             .term_dict
-            .ord_to_term(facet_ord as u64, &mut self.buffer);
+            .ord_to_term(facet_ord as u64, output.inner_buffer_mut());
         assert!(found_term, "Term ordinal {} no found.", facet_ord);
-        let facet_str = str::from_utf8(&self.buffer[..])?;
-        output.set_facet_str(facet_str);
-        Ok(())
     }
 
     /// Return the list of facet ordinals associated to a document.

src/fastfield/multivalued/reader.rs

@@ -82,20 +82,20 @@ mod tests {
 
         let mut facet = Facet::root();
         {
-            facet_reader.facet_from_ord(1, &mut facet).unwrap();
+            facet_reader.facet_from_ord(1, &mut facet);
             assert_eq!(facet, Facet::from("/category"));
         }
         {
-            facet_reader.facet_from_ord(2, &mut facet).unwrap();
+            facet_reader.facet_from_ord(2, &mut facet);
             assert_eq!(facet, Facet::from("/category/cat1"));
         }
         {
-            facet_reader.facet_from_ord(3, &mut facet).unwrap();
+            facet_reader.facet_from_ord(3, &mut facet);
             assert_eq!(format!("{}", facet), "/category/cat2");
             assert_eq!(facet, Facet::from("/category/cat2"));
         }
         {
-            facet_reader.facet_from_ord(4, &mut facet).unwrap();
+            facet_reader.facet_from_ord(4, &mut facet);
             assert_eq!(facet, Facet::from("/category/cat3"));
         }
 

src/indexer/index_writer.rs

@@ -558,8 +558,11 @@ impl IndexWriter {
         // and recreate a new one channels.
         self.recreate_document_channel();
 
-        let former_workers_join_handle =
-            mem::replace(&mut self.workers_join_handle, Vec::new());
+        let mut former_workers_join_handle = Vec::new();
+        swap(
+            &mut former_workers_join_handle,
+            &mut self.workers_join_handle,
+        );
 
         for worker_handle in former_workers_join_handle {
             let indexing_worker_result = worker_handle
@@ -736,7 +739,7 @@ mod tests {
                 index_writer.add_document(doc!(text_field=>"b"));
                 index_writer.add_document(doc!(text_field=>"c"));
             }
-            assert_eq!(index_writer.commit().unwrap(), 3u64);
+            assert_eq!(index_writer.commit().unwrap(), 2u64);
             index.load_searchers().unwrap();
             assert_eq!(num_docs_containing("a"), 0);
             assert_eq!(num_docs_containing("b"), 1);
@@ -799,6 +802,7 @@ mod tests {
             {
                 let mut prepared_commit = index_writer.prepare_commit().expect("commit failed");
                 prepared_commit.set_payload("first commit");
+                assert_eq!(prepared_commit.opstamp(), 100);
                 prepared_commit.commit().expect("commit failed");
             }
             {
@@ -832,6 +836,7 @@ mod tests {
             {
                 let mut prepared_commit = index_writer.prepare_commit().expect("commit failed");
                 prepared_commit.set_payload("first commit");
+                assert_eq!(prepared_commit.opstamp(), 100);
                 prepared_commit.abort().expect("commit failed");
             }
             {

src/indexer/merger.rs

@@ -654,7 +654,6 @@ mod tests {
     use schema::IntOptions;
     use schema::Term;
     use schema::TextFieldIndexing;
-    use schema::INT_INDEXED;
     use std::io::Cursor;
     use DocAddress;
     use IndexWriter;
@@ -984,7 +983,7 @@ mod tests {
                 .wait()
                 .expect("Merging failed");
             index.load_searchers().unwrap();
-            let searcher = index.searcher();
+            let ref searcher = *index.searcher();
             assert_eq!(searcher.segment_readers().len(), 1);
             assert_eq!(searcher.num_docs(), 3);
             assert_eq!(searcher.segment_readers()[0].num_docs(), 3);
@@ -1030,7 +1029,7 @@ mod tests {
             index_writer.commit().unwrap();
 
             index.load_searchers().unwrap();
-            let searcher = index.searcher();
+            let ref searcher = *index.searcher();
             assert_eq!(searcher.segment_readers().len(), 1);
             assert_eq!(searcher.num_docs(), 2);
             assert_eq!(searcher.segment_readers()[0].num_docs(), 2);
@@ -1126,7 +1125,6 @@ mod tests {
         {
             // Test removing all docs
             index_writer.delete_term(Term::from_field_text(text_field, "g"));
-            index_writer.commit().unwrap();
             let segment_ids = index
                 .searchable_segment_ids()
                 .expect("Searchable segments failed.");
@@ -1257,34 +1255,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn test_bug_merge() {
-        let mut schema_builder = schema::Schema::builder();
-        let int_field = schema_builder.add_u64_field("intvals", INT_INDEXED);
-        let index = Index::create_in_ram(schema_builder.build());
-        let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
-        index_writer.add_document(doc!(int_field => 1u64));
-        index_writer.commit().expect("commit failed");
-        index_writer.add_document(doc!(int_field => 1u64));
-        index_writer.commit().expect("commit failed");
-        index.load_searchers().unwrap();
-        let searcher = index.searcher();
-        assert_eq!(searcher.num_docs(), 2);
-        index_writer.delete_term(Term::from_field_u64(int_field, 1));
-        let segment_ids = index
-            .searchable_segment_ids()
-            .expect("Searchable segments failed.");
-        index_writer
-            .merge(&segment_ids)
-            .expect("Failed to initiate merge")
-            .wait()
-            .expect("Merging failed");
-        index.load_searchers().unwrap();
-        // commit has not been called yet. The document should still be
-        // there.
-        assert_eq!(index.searcher().num_docs(), 2);
-    }
-
     #[test]
     fn test_merge_multivalued_int_fields_all_deleted() {
         let mut schema_builder = schema::Schema::builder();

src/indexer/segment_updater.rs

@@ -18,6 +18,7 @@ use indexer::delete_queue::DeleteCursor;
 use indexer::index_writer::advance_deletes;
 use indexer::merger::IndexMerger;
 use indexer::stamper::Stamper;
+use indexer::MergeCandidate;
 use indexer::SegmentEntry;
 use indexer::SegmentSerializer;
 use indexer::{DefaultMergePolicy, MergePolicy};
@@ -44,15 +45,8 @@ use Result;
 /// and flushed.
 ///
 /// This method is not part of tantivy's public API
-pub fn save_new_metas(schema: Schema, directory: &mut Directory) -> Result<()> {
-    save_metas(
-        &IndexMeta {
-            segments: Vec::new(),
-            schema,
-            opstamp: 0u64,
-            payload: None
-        },
-        directory)
+pub fn save_new_metas(schema: Schema, opstamp: u64, directory: &mut Directory) -> Result<()> {
+    save_metas(vec![], schema, opstamp, None, directory)
 }
 
 /// Save the index meta file.
@@ -64,17 +58,20 @@ pub fn save_new_metas(schema: Schema, directory: &mut Directory) -> Result<()> {
 /// and flushed.
 ///
 /// This method is not part of tantivy's public API
-fn save_metas(
-    metas: &IndexMeta,
+pub fn save_metas(
+    segment_metas: Vec<SegmentMeta>,
+    schema: Schema,
+    opstamp: u64,
+    payload: Option<String>,
     directory: &mut Directory,
 ) -> Result<()> {
-//    let metas = IndexMeta {
-//        segments: segment_metas,
-//        schema,
-//        opstamp,
-//        payload,
-//    };
-    let mut buffer = serde_json::to_vec_pretty(metas)?;
+    let metas = IndexMeta {
+        segments: segment_metas,
+        schema,
+        opstamp,
+        payload,
+    };
+    let mut buffer = serde_json::to_vec_pretty(&metas)?;
     writeln!(&mut buffer)?;
     directory.atomic_write(&META_FILEPATH, &buffer[..])?;
     debug!("Saved metas {:?}", serde_json::to_string_pretty(&metas));
@@ -89,11 +86,6 @@ fn save_metas(
 #[derive(Clone)]
 pub struct SegmentUpdater(Arc<InnerSegmentUpdater>);
 
-struct MergeOperation {
-    pub target_opstamp: u64,
-    pub segment_ids: Vec<SegmentId>,
-}
-
 fn perform_merge(
     index: &Index,
     mut segment_entries: Vec<SegmentEntry>,
@@ -134,13 +126,6 @@ fn perform_merge(
 }
 
 struct InnerSegmentUpdater {
-    // we keep a copy of the current active IndexMeta to
-    // avoid loading the file everytime we need it in the
-    // `SegmentUpdater`.
-    //
-    // This should be up to date as all update happen through
-    // the unique active `SegmentUpdater`.
-    active_metas: RwLock<Arc<IndexMeta>>,
     pool: CpuPool,
     index: Index,
     segment_manager: SegmentManager,
@@ -164,9 +149,7 @@ impl SegmentUpdater {
             .name_prefix("segment_updater")
             .pool_size(1)
             .create();
-        let index_meta = index.load_metas()?;
         Ok(SegmentUpdater(Arc::new(InnerSegmentUpdater {
-            active_metas: RwLock::new(Arc::new(index_meta)),
             pool,
             index,
             segment_manager,
@@ -261,18 +244,14 @@ impl SegmentUpdater {
             //
             // Segment 1 from disk 1, Segment 1 from disk 2, etc.
             commited_segment_metas.sort_by_key(|segment_meta| -(segment_meta.max_doc() as i32));
-            let index_meta = IndexMeta {
-                segments: commited_segment_metas,
-                schema: index.schema(),
-                opstamp,
-                payload: commit_message
-            };
             save_metas(
-                &index_meta,
+                commited_segment_metas,
+                index.schema(),
+                opstamp,
+                commit_message,
                 directory.box_clone().borrow_mut(),
             )
             .expect("Could not save metas.");
-            self.store_meta(&index_meta);
         }
     }
 
@@ -307,27 +286,16 @@ impl SegmentUpdater {
     }
 
     pub fn start_merge(&self, segment_ids: &[SegmentId]) -> Result<Receiver<SegmentMeta>> {
+        //let future_merged_segment = */
         let segment_ids_vec = segment_ids.to_vec();
-        let commit_opstamp = self.load_metas().opstamp;
         self.run_async(move |segment_updater| {
-            segment_updater.start_merge_impl(&segment_ids_vec[..], commit_opstamp)
+            segment_updater.start_merge_impl(&segment_ids_vec[..])
         })
         .wait()?
     }
 
-    fn store_meta(&self, index_meta: &IndexMeta) {
-        *self.0.active_metas.write().unwrap() = Arc::new(index_meta.clone());
-    }
-    fn load_metas(&self) -> Arc<IndexMeta> {
-        self.0.active_metas.read().unwrap().clone()
-    }
-
     // `segment_ids` is required to be non-empty.
-    fn start_merge_impl(
-        &self,
-        segment_ids: &[SegmentId],
-        target_opstamp: u64,
-    ) -> Result<Receiver<SegmentMeta>> {
+    fn start_merge_impl(&self, segment_ids: &[SegmentId]) -> Result<Receiver<SegmentMeta>> {
         assert!(!segment_ids.is_empty(), "Segment_ids cannot be empty.");
 
         let segment_updater_clone = self.clone();
@@ -342,6 +310,8 @@ impl SegmentUpdater {
         );
         let (merging_future_send, merging_future_recv) = oneshot();
 
+        let target_opstamp = self.0.stamper.stamp();
+
         // first we need to apply deletes to our segment.
         let merging_join_handle = thread::Builder::new()
             .name(format!("mergingthread-{}", merging_thread_id))
@@ -403,32 +373,11 @@ impl SegmentUpdater {
         // Committed segments cannot be merged with uncommitted_segments.
         // We therefore consider merges using these two sets of segments independently.
         let merge_policy = self.get_merge_policy();
-
-        let current_opstamp = self.0.stamper.stamp();
-        let mut merge_candidates = merge_policy
-            .compute_merge_candidates(&uncommitted_segments)
-            .into_iter()
-            .map(|merge_candidate| MergeOperation {
-                target_opstamp: current_opstamp,
-                segment_ids: merge_candidate.0,
-            })
-            .collect::<Vec<_>>();
-        let commit_opstamp = self.load_metas().opstamp;
-        let committed_merge_candidates = merge_policy
-            .compute_merge_candidates(&committed_segments)
-            .into_iter()
-            .map(|merge_candidate| MergeOperation {
-                target_opstamp: commit_opstamp,
-                segment_ids: merge_candidate.0,
-            })
-            .collect::<Vec<_>>();
-        merge_candidates.extend(committed_merge_candidates.into_iter());
-        for MergeOperation {
-            target_opstamp,
-            segment_ids,
-        } in merge_candidates
-        {
-            match self.start_merge_impl(&segment_ids, target_opstamp) {
+        let mut merge_candidates = merge_policy.compute_merge_candidates(&uncommitted_segments);
+        let committed_merge_candidates = merge_policy.compute_merge_candidates(&committed_segments);
+        merge_candidates.extend_from_slice(&committed_merge_candidates[..]);
+        for MergeCandidate(segment_metas) in merge_candidates {
+            match self.start_merge_impl(&segment_metas) {
                 Ok(merge_future) => {
                     if let Err(e) = merge_future.fuse().poll() {
                         error!("The merge task failed quickly after starting: {:?}", e);
@@ -463,7 +412,12 @@ impl SegmentUpdater {
             info!("End merge {:?}", after_merge_segment_entry.meta());
             let mut delete_cursor = after_merge_segment_entry.delete_cursor().clone();
             if let Some(delete_operation) = delete_cursor.get() {
-                let committed_opstamp = segment_updater.load_metas().opstamp;
+                let committed_opstamp = segment_updater
+                    .0
+                    .index
+                    .load_metas()
+                    .expect("Failed to read opstamp")
+                    .opstamp;
                 if delete_operation.opstamp < committed_opstamp {
                     let index = &segment_updater.0.index;
                     let segment = index.segment(after_merge_segment_entry.meta().clone());
@@ -492,8 +446,8 @@ impl SegmentUpdater {
                 .end_merge(&before_merge_segment_ids, after_merge_segment_entry);
             segment_updater.consider_merge_options();
             info!("save metas");
-            let previous_metas = segment_updater.load_metas();
-            segment_updater.save_metas(previous_metas.opstamp, previous_metas.payload.clone());
+            let previous_metas = segment_updater.0.index.load_metas().unwrap();
+            segment_updater.save_metas(previous_metas.opstamp, previous_metas.payload);
             segment_updater.garbage_collect_files_exec();
         })
         .wait()

src/indexer/segment_writer.rs

@@ -111,18 +111,19 @@ impl SegmentWriter {
             }
             match *field_options.field_type() {
                 FieldType::HierarchicalFacet => {
-                    let facets: Vec<&str> = field_values
+                    let facets: Vec<&[u8]> = field_values
                         .iter()
                         .flat_map(|field_value| match *field_value.value() {
-                            Value::Facet(ref facet) => Some(facet.encoded_str()),
+                            Value::Facet(ref facet) => Some(facet.encoded_bytes()),
                             _ => {
                                 panic!("Expected hierarchical facet");
                             }
                         })
                         .collect();
                     let mut term = Term::for_field(field); // we set the Term
-                    for fake_str in facets {
+                    for facet_bytes in facets {
                         let mut unordered_term_id_opt = None;
+                        let fake_str = unsafe { str::from_utf8_unchecked(facet_bytes) };
                         FacetTokenizer.token_stream(fake_str).process(&mut |token| {
                             term.set_text(&token.text);
                             let unordered_term_id =

src/indexer/stamper.rs

@@ -1,68 +1,50 @@
-use std::sync::Arc;
-use std::sync::atomic::Ordering;
-
-
 // AtomicU64 have not landed in stable.
 // For the moment let's just use AtomicUsize on
 // x86/64 bit platform, and a mutex on other platform.
-#[cfg(target_arch = "x86_64")]
+
+#[cfg(target = "x86_64")]
 mod archicture_impl {
 
     use std::sync::atomic::{AtomicUsize, Ordering};
+    use std::sync::Arc;
 
-    #[derive(Default)]
-    pub struct AtomicU64Ersatz(AtomicUsize);
+    #[derive(Clone, Default)]
+    pub struct Stamper(Arc<AtomicU64>);
 
-    impl AtomicU64Ersatz {
-        pub fn new(first_opstamp: u64) -> AtomicU64Ersatz {
-            AtomicU64Ersatz(AtomicUsize::new(first_opstamp as usize))
+    impl Stamper {
+        pub fn new(first_opstamp: u64) -> Stamper {
+            Stamper(Arc::new(AtomicU64::new(first_opstamp)))
         }
 
-        pub fn fetch_add(&self, val: u64, order: Ordering) -> u64 {
-            self.0.fetch_add(val as usize, order) as u64
+        pub fn stamp(&self) -> u64 {
+            self.0.fetch_add(1u64, Ordering::SeqCst) as u64
         }
     }
 }
 
-#[cfg(not(target_arch = "x86_64"))]
+#[cfg(not(target = "x86_64"))]
 mod archicture_impl {
 
-    use std::sync::atomic::Ordering;
-    /// Under other architecture, we rely on a mutex.
-    use std::sync::RwLock;
+    use std::sync::{Arc, Mutex};
 
-    #[derive(Default)]
-    pub struct AtomicU64Ersatz(RwLock<u64>);
+    #[derive(Clone, Default)]
+    pub struct Stamper(Arc<Mutex<u64>>);
 
-    impl AtomicU64Ersatz {
-        pub fn new(first_opstamp: u64) -> AtomicU64Ersatz {
-            AtomicU64Ersatz(RwLock::new(first_opstamp))
+    impl Stamper {
+        pub fn new(first_opstamp: u64) -> Stamper {
+            Stamper(Arc::new(Mutex::new(first_opstamp)))
         }
 
-        pub fn fetch_add(&self, incr: u64, _order: Ordering) -> u64 {
-            let mut lock = self.0.write().unwrap();
-            let previous_val = *lock;
-            *lock = previous_val + incr;
+        pub fn stamp(&self) -> u64 {
+            let mut guard = self.0.lock().expect("Failed to lock the stamper");
+            let previous_val = *guard;
+            *guard = previous_val + 1;
             previous_val
         }
     }
 }
 
-use self::archicture_impl::AtomicU64Ersatz;
-
-#[derive(Clone, Default)]
-pub struct Stamper(Arc<AtomicU64Ersatz>);
-
-impl Stamper {
-    pub fn new(first_opstamp: u64) -> Stamper {
-        Stamper(Arc::new(AtomicU64Ersatz::new(first_opstamp)))
-    }
-
-    pub fn stamp(&self) -> u64 {
-        self.0.fetch_add(1u64, Ordering::SeqCst) as u64
-    }
-}
-
+pub use self::archicture_impl::Stamper;
 
 #[cfg(test)]
 mod test {

src/postings/segment_postings.rs

@@ -126,6 +126,7 @@ impl SegmentPostings {
 fn exponential_search(target: u32, arr: &[u32]) -> (usize, usize) {
     let mut start = 0;
     let end = arr.len();
+    debug_assert!(target >= arr[start]);
     debug_assert!(target <= arr[end - 1]);
     let mut jump = 1;
     loop {
@@ -215,10 +216,11 @@ impl DocSet for SegmentPostings {
 
         // we're in the right block now, start with an exponential search
         let block_docs = self.block_cursor.docs();
+
+        debug_assert!(target >= self.doc());
         let new_cur = self
             .cur
             .wrapping_add(search_within_block(&block_docs[self.cur..], target));
-
         if need_positions {
             sum_freqs_skipped += self.block_cursor.freqs()[self.cur..new_cur]
                 .iter()
@@ -620,7 +622,6 @@ impl<'b> Streamer<'b> for BlockSegmentPostings {
 #[cfg(test)]
 mod tests {
 
-    use super::exponential_search;
     use super::search_within_block;
     use super::BlockSegmentPostings;
     use super::BlockSegmentPostingsSkipResult;
@@ -634,7 +635,6 @@ mod tests {
     use schema::Term;
     use schema::INT_INDEXED;
     use DocId;
-    use SkipResult;
 
     #[test]
     fn test_empty_segment_postings() {
@@ -662,16 +662,6 @@ mod tests {
             .0
     }
 
-    #[test]
-    fn test_exponentiel_search() {
-        assert_eq!(exponential_search(0, &[1, 2]), (0, 1));
-        assert_eq!(exponential_search(1, &[1, 2]), (0, 1));
-        assert_eq!(
-            exponential_search(7, &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]),
-            (3, 7)
-        );
-    }
-
     fn util_test_search_within_block(block: &[u32], target: u32) {
         assert_eq!(
             search_within_block(block, target),
@@ -703,7 +693,7 @@ mod tests {
 
     #[test]
     fn test_block_segment_postings() {
-        let mut block_segments = build_block_postings(&(0..100_000).collect::<Vec<u32>>());
+        let mut block_segments = build_block_postings((0..100_000).collect::<Vec<u32>>());
         let mut offset: u32 = 0u32;
         // checking that the block before calling advance is empty
         assert!(block_segments.docs().is_empty());
@@ -717,44 +707,14 @@ mod tests {
         }
     }
 
-    #[test]
-    fn test_skip_right_at_new_block() {
-        let mut doc_ids = (0..128).collect::<Vec<u32>>();
-        doc_ids.push(129);
-        doc_ids.push(130);
-        {
-            let block_segments = build_block_postings(&doc_ids);
-            let mut docset = SegmentPostings::from_block_postings(block_segments, None);
-            assert_eq!(docset.skip_next(128), SkipResult::OverStep);
-            assert_eq!(docset.doc(), 129);
-            assert!(docset.advance());
-            assert_eq!(docset.doc(), 130);
-            assert!(!docset.advance());
-        }
-        {
-            let block_segments = build_block_postings(&doc_ids);
-            let mut docset = SegmentPostings::from_block_postings(block_segments, None);
-            assert_eq!(docset.skip_next(129), SkipResult::Reached);
-            assert_eq!(docset.doc(), 129);
-            assert!(docset.advance());
-            assert_eq!(docset.doc(), 130);
-            assert!(!docset.advance());
-        }
-        {
-            let block_segments = build_block_postings(&doc_ids);
-            let mut docset = SegmentPostings::from_block_postings(block_segments, None);
-            assert_eq!(docset.skip_next(131), SkipResult::End);
-        }
-    }
-
-    fn build_block_postings(docs: &[DocId]) -> BlockSegmentPostings {
+    fn build_block_postings(docs: Vec<DocId>) -> BlockSegmentPostings {
         let mut schema_builder = Schema::builder();
         let int_field = schema_builder.add_u64_field("id", INT_INDEXED);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut index_writer = index.writer_with_num_threads(1, 40_000_000).unwrap();
         let mut last_doc = 0u32;
-        for &doc in docs {
+        for doc in docs {
             for _ in last_doc..doc {
                 index_writer.add_document(doc!(int_field=>1u64));
             }
@@ -774,7 +734,7 @@ mod tests {
     #[test]
     fn test_block_segment_postings_skip() {
         for i in 0..4 {
-            let mut block_postings = build_block_postings(&[3]);
+            let mut block_postings = build_block_postings(vec![3]);
             assert_eq!(
                 block_postings.skip_to(i),
                 BlockSegmentPostingsSkipResult::Success(0u32)
@@ -784,7 +744,7 @@ mod tests {
                 BlockSegmentPostingsSkipResult::Terminated
             );
         }
-        let mut block_postings = build_block_postings(&[3]);
+        let mut block_postings = build_block_postings(vec![3]);
         assert_eq!(
             block_postings.skip_to(4u32),
             BlockSegmentPostingsSkipResult::Terminated
@@ -797,7 +757,7 @@ mod tests {
         for i in 0..1300 {
             docs.push((i * i / 100) + i);
         }
-        let mut block_postings = build_block_postings(&docs[..]);
+        let mut block_postings = build_block_postings(docs.clone());
         for i in vec![0, 424, 10000] {
             assert_eq!(
                 block_postings.skip_to(i),

src/postings/stacker/mod.rs

@@ -1,7 +1,9 @@
 mod expull;
 mod memory_arena;
+mod murmurhash2;
 mod term_hashmap;
 
 pub use self::expull::ExpUnrolledLinkedList;
 pub use self::memory_arena::{Addr, ArenaStorable, MemoryArena};
+use self::murmurhash2::murmurhash2;
 pub use self::term_hashmap::{compute_table_size, TermHashMap};

src/postings/stacker/murmurhash2.rs

@@ -0,0 +1,87 @@
+use std::ptr;
+const SEED: u32 = 3_242_157_231u32;
+const M: u32 = 0x5bd1_e995;
+
+#[inline(always)]
+pub fn murmurhash2(key: &[u8]) -> u32 {
+    #[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
+    let mut key_ptr: *const u32 = key.as_ptr() as *const u32;
+    let len = key.len() as u32;
+    let mut h: u32 = SEED ^ len;
+
+    let num_blocks = len >> 2;
+    for _ in 0..num_blocks {
+        let mut k: u32 = unsafe { ptr::read_unaligned(key_ptr) }; // ok because of num_blocks definition
+        k = k.wrapping_mul(M);
+        k ^= k >> 24;
+        k = k.wrapping_mul(M);
+        h = h.wrapping_mul(M);
+        h ^= k;
+        key_ptr = key_ptr.wrapping_offset(1);
+    }
+
+    // Handle the last few bytes of the input array
+    let remaining: &[u8] = &key[key.len() & !3..];
+    match remaining.len() {
+        3 => {
+            h ^= u32::from(remaining[2]) << 16;
+            h ^= u32::from(remaining[1]) << 8;
+            h ^= u32::from(remaining[0]);
+            h = h.wrapping_mul(M);
+        }
+        2 => {
+            h ^= u32::from(remaining[1]) << 8;
+            h ^= u32::from(remaining[0]);
+            h = h.wrapping_mul(M);
+        }
+        1 => {
+            h ^= u32::from(remaining[0]);
+            h = h.wrapping_mul(M);
+        }
+        _ => {}
+    }
+    h ^= h >> 13;
+    h = h.wrapping_mul(M);
+    h ^ (h >> 15)
+}
+
+#[cfg(test)]
+mod test {
+
+    use super::murmurhash2;
+    use std::collections::HashSet;
+
+    #[test]
+    fn test_murmur() {
+        let s1 = "abcdef";
+        let s2 = "abcdeg";
+        for i in 0..5 {
+            assert_eq!(
+                murmurhash2(&s1[i..5].as_bytes()),
+                murmurhash2(&s2[i..5].as_bytes())
+            );
+        }
+    }
+
+    #[test]
+    fn test_murmur_against_reference_impl() {
+        assert_eq!(murmurhash2("".as_bytes()), 3632506080);
+        assert_eq!(murmurhash2("a".as_bytes()), 455683869);
+        assert_eq!(murmurhash2("ab".as_bytes()), 2448092234);
+        assert_eq!(murmurhash2("abc".as_bytes()), 2066295634);
+        assert_eq!(murmurhash2("abcd".as_bytes()), 2588571162);
+        assert_eq!(murmurhash2("abcde".as_bytes()), 2988696942);
+        assert_eq!(murmurhash2("abcdefghijklmnop".as_bytes()), 2350868870);
+    }
+
+    #[test]
+    fn test_murmur_collisions() {
+        let mut set: HashSet<u32> = HashSet::default();
+        for i in 0..10_000 {
+            let s = format!("hash{}", i);
+            let hash = murmurhash2(s.as_bytes());
+            set.insert(hash);
+        }
+        assert_eq!(set.len(), 10_000);
+    }
+}

src/postings/stacker/term_hashmap.rs

@@ -1,7 +1,4 @@
-extern crate murmurhash32;
-
-use self::murmurhash32::murmurhash2;
-
+use super::murmurhash2;
 use super::{Addr, ArenaStorable, MemoryArena};
 use std::iter;
 use std::mem;
@@ -209,7 +206,7 @@ impl TermHashMap {
             self.resize();
         }
         let key_bytes: &[u8] = key.as_ref();
-        let hash = murmurhash2(key.as_ref());
+        let hash = murmurhash2::murmurhash2(key.as_ref());
         let mut probe = self.probe(hash);
         loop {
             let bucket = probe.next_probe();

src/schema/facet.rs

@@ -6,7 +6,6 @@ use std::borrow::Cow;
 use std::fmt::{self, Debug, Display, Formatter};
 use std::io::{self, Read, Write};
 use std::str;
-use std::string::FromUtf8Error;
 
 const SLASH_BYTE: u8 = b'/';
 const ESCAPE_BYTE: u8 = b'\\';
@@ -15,10 +14,6 @@ const ESCAPE_BYTE: u8 = b'\\';
 /// representation of facets.
 pub const FACET_SEP_BYTE: u8 = 0u8;
 
-/// `char` used as a level separation in the binary
-/// representation of facets. (It is the null codepoint.)
-pub const FACET_SEP_CHAR: char = '\u{0}';
-
 /// A Facet represent a point in a given hierarchy.
 ///
 /// They are typically represented similarly to a filepath.
@@ -31,18 +26,18 @@ pub const FACET_SEP_CHAR: char = '\u{0}';
 /// its facet. In the example above, `/electronics/tv_and_video/`
 /// and `/electronics`.
 #[derive(Clone, Eq, Hash, PartialEq, Ord, PartialOrd)]
-pub struct Facet(String);
+pub struct Facet(Vec<u8>);
 
 impl Facet {
     /// Returns a new instance of the "root facet"
     /// Equivalent to `/`.
     pub fn root() -> Facet {
-        Facet("".to_string())
+        Facet(vec![])
     }
 
     /// Returns true iff the facet is the root facet `/`.
     pub fn is_root(&self) -> bool {
-        self.encoded_str().is_empty()
+        self.encoded_bytes().is_empty()
     }
 
     /// Returns a binary representation of the facet.
@@ -54,19 +49,13 @@ impl Facet {
     /// This representation has the benefit of making it possible to
     /// express "being a child of a given facet" as a range over
     /// the term ordinals.
-    pub fn encoded_str(&self) -> &str {
+    pub fn encoded_bytes(&self) -> &[u8] {
         &self.0
     }
 
-    pub(crate) fn from_encoded_string(facet_string: String) -> Facet {
-        Facet(facet_string)
-    }
-
     /// Creates a `Facet` from its binary representation.
-    pub fn from_encoded(encoded_bytes: Vec<u8>) -> Result<Facet, FromUtf8Error> {
-        // facet bytes validation. `0u8` is used a separator but that is still legal utf-8
-        //Ok(Facet(String::from_utf8(encoded_bytes)?))
-        String::from_utf8(encoded_bytes).map(Facet)
+    pub(crate) unsafe fn from_encoded(encoded_bytes: Vec<u8>) -> Facet {
+        Facet(encoded_bytes)
     }
 
     /// Parse a text representation of a facet.
@@ -90,37 +79,36 @@ impl Facet {
         Path: IntoIterator,
         Path::Item: ToString,
     {
-        let mut facet_string: String = String::with_capacity(100);
+        let mut facet_bytes: Vec<u8> = Vec::with_capacity(100);
         let mut step_it = path.into_iter();
         if let Some(step) = step_it.next() {
-            facet_string.push_str(&step.to_string());
+            facet_bytes.extend_from_slice(step.to_string().as_bytes());
         }
         for step in step_it {
-            facet_string.push(FACET_SEP_CHAR);
-            facet_string.push_str(&step.to_string());
+            facet_bytes.push(FACET_SEP_BYTE);
+            facet_bytes.extend_from_slice(step.to_string().as_bytes());
         }
-        Facet(facet_string)
+        Facet(facet_bytes)
     }
 
     /// Accessor for the inner buffer of the `Facet`.
-    pub(crate) fn set_facet_str(&mut self, facet_str: &str) {
-        self.0.clear();
-        self.0.push_str(facet_str);
+    pub(crate) fn inner_buffer_mut(&mut self) -> &mut Vec<u8> {
+        &mut self.0
     }
 
     /// Returns `true` iff other is a subfacet of `self`.
     pub fn is_prefix_of(&self, other: &Facet) -> bool {
-        let self_str = self.encoded_str();
-        let other_str = other.encoded_str();
-        self_str.len() < other_str.len()
-            && other_str.starts_with(self_str)
-            && other_str.as_bytes()[self_str.len()] == FACET_SEP_BYTE
+        let self_bytes: &[u8] = self.encoded_bytes();
+        let other_bytes: &[u8] = other.encoded_bytes();
+        self_bytes.len() < other_bytes.len()
+            && other_bytes.starts_with(self_bytes)
+            && other_bytes[self_bytes.len()] == 0u8
     }
 }
 
-impl Borrow<str> for Facet {
-    fn borrow(&self) -> &str {
-        self.encoded_str()
+impl Borrow<[u8]> for Facet {
+    fn borrow(&self) -> &[u8] {
+        self.encoded_bytes()
     }
 }
 
@@ -132,51 +120,45 @@ impl<'a, T: ?Sized + AsRef<str>> From<&'a T> for Facet {
             Idle,
         }
         let path: &str = path_asref.as_ref();
-        assert!(!path.is_empty());
-        assert!(path.starts_with("/"));
-        let mut facet_encoded = String::new();
+        let mut facet_encoded = Vec::new();
         let mut state = State::Idle;
         let path_bytes = path.as_bytes();
-        let mut last_offset = 1;
-        for i in 1..path_bytes.len() {
-            let c = path_bytes[i];
+        for &c in &path_bytes[1..] {
             match (state, c) {
-                (State::Idle, ESCAPE_BYTE) => {
-                    facet_encoded.push_str(&path[last_offset..i]);
-                    last_offset = i + 1;
-                    state = State::Escaped
-                }
+                (State::Idle, ESCAPE_BYTE) => state = State::Escaped,
                 (State::Idle, SLASH_BYTE) => {
-                    facet_encoded.push_str(&path[last_offset..i]);
-                    facet_encoded.push(FACET_SEP_CHAR);
-                    last_offset = i + 1;
+                    facet_encoded.push(FACET_SEP_BYTE);
                 }
-                (State::Escaped, _escaped_char) => {
+                (State::Escaped, any_char) => {
                     state = State::Idle;
+                    facet_encoded.push(any_char);
+                }
+                (State::Idle, other_char) => {
+                    facet_encoded.push(other_char);
                 }
-                (State::Idle, _any_char) => {}
             }
         }
-        facet_encoded.push_str(&path[last_offset..]);
         Facet(facet_encoded)
     }
 }
 
 impl BinarySerializable for Facet {
     fn serialize<W: Write>(&self, writer: &mut W) -> io::Result<()> {
-        <String as BinarySerializable>::serialize(&self.0, writer)
+        <Vec<u8> as BinarySerializable>::serialize(&self.0, writer)
     }
 
     fn deserialize<R: Read>(reader: &mut R) -> io::Result<Self> {
-        Ok(Facet(<String as BinarySerializable>::deserialize(reader)?))
+        let bytes = <Vec<u8> as BinarySerializable>::deserialize(reader)?;
+        Ok(Facet(bytes))
     }
 }
 
 impl Display for Facet {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        for step in self.0.split(FACET_SEP_CHAR) {
+        for step in self.0.split(|&b| b == FACET_SEP_BYTE) {
             write!(f, "/")?;
-            write!(f, "{}", escape_slashes(step))?;
+            let step_str = unsafe { str::from_utf8_unchecked(step) };
+            write!(f, "{}", escape_slashes(step_str))?;
         }
         Ok(())
     }

src/schema/term.rs

@@ -32,7 +32,7 @@ impl Term {
 
     /// Creates a `Term` given a facet.
     pub fn from_facet(field: Field, facet: &Facet) -> Term {
-        let bytes = facet.encoded_str().as_bytes();
+        let bytes = facet.encoded_bytes();
         let buffer = Vec::with_capacity(4 + bytes.len());
         let mut term = Term(buffer);
         term.set_field(field);
@@ -68,7 +68,12 @@ impl Term {
         term
     }
 
-    /// Creates a new Term for a given field.
+    /// Creates a new Term with an empty buffer,
+    /// but with a given capacity.
+    ///
+    /// It is declared unsafe, as the term content
+    /// is not initialized, and a call to `.field()`
+    /// would panic.
     pub(crate) fn for_field(field: Field) -> Term {
         let mut term = Term(Vec::with_capacity(100));
         term.set_field(field);

src/termdict/mod.rs

@@ -167,7 +167,7 @@ mod tests {
         let mut term_string = String::new();
         while term_it.advance() {
             //let term = Term::from_bytes(term_it.key());
-            term_string.push_str(str::from_utf8(term_it.key()).expect("test"));
+            term_string.push_str(unsafe { str::from_utf8_unchecked(term_it.key()) }); // ok test
         }
         assert_eq!(&*term_string, "abcdef");
     }

src/tokenizer/facet_tokenizer.rs

@@ -1,5 +1,6 @@
 use super::{Token, TokenStream, Tokenizer};
 use schema::FACET_SEP_BYTE;
+use std::str;
 
 /// The `FacetTokenizer` process a `Facet` binary representation
 /// and emits a token for all of its parent.
@@ -56,11 +57,12 @@ impl<'a> TokenStream for FacetTokenStream<'a> {
                     .position(|b| b == FACET_SEP_BYTE)
                     .map(|pos| cursor + 1 + pos)
                 {
-                    let facet_part = &self.text[cursor..next_sep_pos];
+                    let facet_part =
+                        unsafe { str::from_utf8_unchecked(&bytes[cursor..next_sep_pos]) };
                     self.token.text.push_str(facet_part);
                     self.state = State::UpToPosition(next_sep_pos);
                 } else {
-                    let facet_part = &self.text[cursor..];
+                    let facet_part = unsafe { str::from_utf8_unchecked(&bytes[cursor..]) };
                     self.token.text.push_str(facet_part);
                     self.state = State::Terminated;
                 }
@@ -84,6 +86,7 @@ mod tests {
 
     use super::FacetTokenizer;
     use schema::Facet;
+    use std::str;
     use tokenizer::{Token, TokenStream, Tokenizer};
 
     #[test]
@@ -92,11 +95,11 @@ mod tests {
         let mut tokens = vec![];
         {
             let mut add_token = |token: &Token| {
-                let facet = Facet::from_encoded(token.text.as_bytes().to_owned()).unwrap();
+                let facet = unsafe { Facet::from_encoded(token.text.as_bytes().to_owned()) }; // ok test
                 tokens.push(format!("{}", facet));
             };
             FacetTokenizer
-                .token_stream(facet.encoded_str())
+                .token_stream(unsafe { str::from_utf8_unchecked(facet.encoded_bytes()) })
                 .process(&mut add_token);
         }
         assert_eq!(tokens.len(), 4);
@@ -112,11 +115,11 @@ mod tests {
         let mut tokens = vec![];
         {
             let mut add_token = |token: &Token| {
-                let facet = Facet::from_encoded(token.text.as_bytes().to_owned()).unwrap(); // ok test
+                let facet = unsafe { Facet::from_encoded(token.text.as_bytes().to_owned()) }; // ok test
                 tokens.push(format!("{}", facet));
             };
             FacetTokenizer
-                .token_stream(facet.encoded_str()) // ok test
+                .token_stream(unsafe { str::from_utf8_unchecked(facet.encoded_bytes()) }) // ok test
                 .process(&mut add_token);
         }
         assert_eq!(tokens.len(), 1);