From 4e4937ebb6242bbe2f4cab307a015b5c905e2fe4 Mon Sep 17 00:00:00 2001
From: Paul Masurel <paul.masurel@gmail.com>
Date: Thu, 28 Jul 2016 21:29:27 +0900
Subject: [PATCH] Query parser.

---
 src/query/multi_term_query.rs |  1 +
 src/query/query_parser.rs     | 84 +++++++++++++++++++++++++++++------
 2 files changed, 72 insertions(+), 13 deletions(-)

diff --git a/src/query/multi_term_query.rs b/src/query/multi_term_query.rs
index 99e455f8d..e7a0f393b 100644
--- a/src/query/multi_term_query.rs
+++ b/src/query/multi_term_query.rs
@@ -14,6 +14,7 @@ use postings::DocSet;
 use query::MultiTermScorer;
 use std::iter;
 
+
 pub struct MultiTermQuery {
     terms: Vec<Term>,    
 }
diff --git a/src/query/query_parser.rs b/src/query/query_parser.rs
index 3e8329239..e3a433134 100644
--- a/src/query/query_parser.rs
+++ b/src/query/query_parser.rs
@@ -1,20 +1,81 @@
-use combine::primitives::Stream;
 use combine::*;
+use collector::Collector;
+use std::io;
+use core::searcher::Searcher;
+use common::TimerTree;
+use query::{Query, MultiTermQuery};
+use schema::Schema;
+use schema::{Term, Field};
 
-
-pub struct QueryParser
-{
-    // split_ptn: Regex,
+pub enum ParsingError {
+    SyntaxError,
+    FieldDoesNotExist(String),
 }
 
+pub struct QueryParser {
+    schema: Schema,
+    default_field: Field,
+}
+
+pub enum StandardQuery {
+    MultiTerm(MultiTermQuery),
+}
+
+impl Query for StandardQuery {
+    fn search<C: Collector>(&self, searcher: &Searcher, collector: &mut C) -> io::Result<TimerTree> {
+        match *self {
+            StandardQuery::MultiTerm(ref q) => {
+                q.search(searcher, collector)
+            }
+        }
+    }
+}
+
+
 impl QueryParser {
-    pub fn new() -> QueryParser {
-        QueryParser {}
+    pub fn new(schema: Schema,
+               default_field: Field) -> QueryParser {
+        QueryParser {
+            schema: schema,
+            default_field: default_field,
+        }
     }
 
-    // pub fn parse_query() {
+    // TODO check that the term is str.
+    // we only support str field for the moment
+    fn transform_literal(&self, literal: Literal) -> Result<Term, ParsingError> {
+        match literal {
+            Literal::DefaultField(val) => {
+                Ok(Term::from_field_text(self.default_field, &val))
+            },
+            Literal::WithField(field_name, val) => {
+                match self.schema.get_field(&field_name) {
+                    Some(field) => {
+                        Ok(Term::from_field_text(field, &val))
+                    }
+                    None => {
+                        Err(ParsingError::FieldDoesNotExist(field_name))
+                    }
+                } 
+            }
+        }
+    }
 
-    // }
+    pub fn parse_query(&self, query: &str) -> Result<StandardQuery, ParsingError> {
+        match parser(query_language).parse(query) {
+            Ok(literals) => {
+                let terms_result: Result<Vec<Term>, ParsingError> = literals.0.into_iter()
+                    .map(|literal| self.transform_literal(literal))
+                    .collect();
+                terms_result
+                    .map(MultiTermQuery::new)
+                    .map(StandardQuery::MultiTerm)
+            }  
+            Err(_) => {
+                Err(ParsingError::SyntaxError)
+            }
+        }
+    }
 
 }
 
@@ -24,8 +85,7 @@ pub enum Literal {
     DefaultField(String),
 }
 
-pub fn query_language<I>(input: State<I>) -> ParseResult<Vec<Literal>, I>
-    where I: Stream<Item=char>
+pub fn query_language(input: State<&str>) -> ParseResult<Vec<Literal>, &str>
 {
     let literal = || {
         let term_val = || {
@@ -33,14 +93,12 @@ pub fn query_language<I>(input: State<I>) -> ParseResult<Vec<Literal>, I>
             let phrase =  
                 (char('"'), many1(satisfy(|c| c != '"')), char('"'),)
                 .map(|(_, s, _)| s);
-            
             phrase.or(word)
         };
 
         let field = many1(letter());
         let term_query = (field, char(':'), term_val())
             .map(|(field,_, value)| Literal::WithField(field, value));
-        
         let term_default_field = term_val().map(|w| Literal::DefaultField(w));
         try(term_query)
             .or(term_default_field)