perf(java): find implementations in the project sources first (#1616)

JDT LS answers textDocument/implementation by building the type hierarchy over every dependency jar, so Go to Implementation and the implemented/overridden gutter markers were slow in projects with many dependencies. The app-owned JDT LS bundle (1.4.0) adds openidea.java.implementations: subtypes, or overriding methods with type arguments substituted and abstract ones left out, within the workspace's source folders only. ide-lsp asks it first and falls back to the standard request when the sources have none or the command is missing.

java/java-usages/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: OpenIDEA Java usages
 Bundle-SymbolicName: ai.openidea.usages;singleton:=true
-Bundle-Version: 1.3.0
+Bundle-Version: 1.4.0
 Bundle-RequiredExecutionEnvironment: JavaSE-21
 Require-Bundle: org.eclipse.jdt.ls.core,org.eclipse.jdt.core,
  org.eclipse.jdt.core.manipulation,org.eclipse.core.runtime,

java/java-usages/README.md

@@ -57,7 +57,7 @@ is not a claim of full IntelliJ feature parity.
 ## Rebuild and delivery
 
 The checked-in jar is embedded by ide-sdk `include_bytes!`, installed as
-`java-usages-1.3.0.jar`, and added alongside existing initialization bundles.
+`java-usages-1.4.0.jar`, and added alongside existing initialization bundles.
 Users need no compiler, Maven or Python. Manifest/install version must change
 when replacing the bundle because OSGi caches bundles.
 
@@ -75,6 +75,9 @@ unrelated content and non-Java resource changes; its reproducible SHA-256 is
 `cbae3e3a0bcf2818b4cc9d98998bd9b81f92e1ae7803dc757134485f9776a4e1`.
 Version 1.3.0 adds the class-hierarchy refactoring commands; its reproducible SHA-256 is
 `cca4cc385ace286111730d2a6164333b8958d74d69631548eadca8863255c24a`.
+Version 1.4.0 adds `openidea.java.implementations` (Go to Implementation in the workspace's
+source folders, before the standard request that also searches every dependency jar); its
+reproducible SHA-256 is `d7601493eda846811b4bb8bfe7f3d56e3234a45e663648210db3937cebc770a5`.
 
 ```sh
 export PATH=/path/to/jdk25/bin:$PATH

java/java-usages/plugin.xml

@@ -7,6 +7,9 @@
     <delegateCommandHandler class="ai.openidea.configuration.ConfigurationCommand">
       <command id="openidea.java.configuration"/>
     </delegateCommandHandler>
+    <delegateCommandHandler class="ai.openidea.implementations.ImplementationsCommand">
+      <command id="openidea.java.implementations"/>
+    </delegateCommandHandler>
     <delegateCommandHandler class="ai.openidea.hierarchy.HierarchyCommand">
       <command id="openidea.java.hierarchy.members"/>
       <command id="openidea.java.hierarchy.refactor"/>

java/java-usages/src/ai/openidea/implementations/ImplementationsCommand.java

@@ -0,0 +1,67 @@
+package ai.openidea.implementations;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.OperationCanceledException;
+import org.eclipse.jdt.core.*;
+import org.eclipse.jdt.internal.corext.util.MethodOverrideTester;
+import org.eclipse.jdt.ls.core.internal.IDelegateCommandHandler;
+import org.eclipse.jdt.ls.core.internal.JDTUtils;
+import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
+import org.eclipse.lsp4j.Location;
+
+/**
+ * Implementations of the type or method at a position, looked up in the workspace's source
+ * folders only. The standard request builds the type hierarchy over every dependency jar too,
+ * which takes long in a project with many dependencies; the client falls back to it when the
+ * sources have none.
+ */
+public final class ImplementationsCommand implements IDelegateCommandHandler {
+    @Override
+    public Object executeCommand(String command, List<Object> arguments, IProgressMonitor monitor) throws Exception {
+        String uri = (String) arguments.get(0);
+        int line = ((Number) arguments.get(1)).intValue();
+        int column = ((Number) arguments.get(2)).intValue();
+        List<Location> result = new ArrayList<>();
+        ITypeRoot root = JDTUtils.resolveTypeRoot(uri);
+        if (root == null) return result;
+        var preferences = JavaLanguageServerPlugin.getPreferencesManager();
+        IJavaElement element = JDTUtils.findElementAtSelection(root, line, column, preferences, monitor);
+        IMethod method = null;
+        IType type;
+        if (element instanceof IMethod m) {
+            int flags = m.getFlags();
+            if (m.isConstructor() || Flags.isStatic(flags) || Flags.isPrivate(flags) || Flags.isFinal(flags)) return result;
+            method = m;
+            type = m.getDeclaringType();
+        } else if (element instanceof IType t) {
+            type = t;
+        } else {
+            return result;
+        }
+        if (type == null || type.getJavaProject() == null) return result;
+        IRegion sources = JavaCore.newRegion();
+        for (IJavaProject project : JavaCore.create(ResourcesPlugin.getWorkspace().getRoot()).getJavaProjects()) {
+            for (IPackageFragmentRoot fragmentRoot : project.getPackageFragmentRoots()) {
+                if (fragmentRoot.getKind() == IPackageFragmentRoot.K_SOURCE) sources.add(fragmentRoot);
+            }
+        }
+        ITypeHierarchy hierarchy = type.getJavaProject().newTypeHierarchy(type, sources, monitor);
+        for (IType subtype : hierarchy.getAllSubtypes(type)) {
+            if (monitor.isCanceled()) throw new OperationCanceledException();
+            IMember found;
+            if (method == null) {
+                found = subtype.isInterface() ? null : subtype;
+            } else {
+                // Seen from the subtype, so its type arguments substitute the method's type variables.
+                IMethod overriding = new MethodOverrideTester(subtype, hierarchy).findOverridingMethodInType(subtype, method);
+                found = overriding == null || Flags.isAbstract(overriding.getFlags()) ? null : overriding;
+            }
+            Location location = found == null ? null : JDTUtils.toLocation(found);
+            if (location != null) result.add(location);
+        }
+        return result;
+    }
+}

java/java-usages/tests/implementations.py

@@ -0,0 +1,192 @@
+"""Go to Implementation in project sources against a real JDT LS. Argument: jdtls home."""
+import json
+import pathlib
+import platform
+import queue
+import shutil
+import subprocess
+import sys
+import tempfile
+import threading
+import time
+import urllib.parse
+
+home = pathlib.Path(sys.argv[1]).resolve()
+bundle = pathlib.Path(__file__).resolve().parents[1] / 'openidea-java-usages.jar'
+work = pathlib.Path(tempfile.mkdtemp(prefix='openidea-implementations-'))
+config = work / 'config'
+config.mkdir()
+system, machine = platform.system(), platform.machine().lower()
+config_name = {'Windows': 'config_win', 'Darwin': 'config_mac'}.get(system, 'config_linux')
+config_names = ([config_name + '_arm'] if machine in ('arm64', 'aarch64') else []) + [config_name]
+config_source = next(home / name / 'config.ini' for name in config_names if (home / name / 'config.ini').is_file())
+(config / 'config.ini').write_bytes(config_source.read_bytes())
+project = work / 'project'
+(project / 'src/zoo').mkdir(parents=True)
+(project / '.project').write_text('<projectDescription><name>zoo</name><buildSpec><buildCommand><name>org.eclipse.jdt.core.javabuilder</name></buildCommand></buildSpec><natures><nature>org.eclipse.jdt.core.javanature</nature></natures></projectDescription>')
+(project / '.classpath').write_text('<classpath><classpathentry kind="src" path="src"/><classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/><classpathentry kind="output" path="bin"/></classpath>')
+sources = {
+    'Repo.java': '''package zoo;
+
+public interface Repo<T> {
+    void save(T item);
+
+    default String name() {
+        return "repo";
+    }
+}
+''',
+    'SubRepo.java': '''package zoo;
+
+public interface SubRepo extends Repo<String> {
+}
+''',
+    'Base.java': '''package zoo;
+
+public abstract class Base implements Repo<Integer> {
+    public abstract void save(Integer item);
+}
+''',
+    'Numbers.java': '''package zoo;
+
+public class Numbers extends Base {
+    public void save(Integer item) {
+    }
+}
+''',
+    'Words.java': '''package zoo;
+
+public class Words implements SubRepo {
+    public void save(String item) {
+    }
+
+    public String name() {
+        return "words";
+    }
+}
+''',
+    'Task.java': '''package zoo;
+
+public class Task implements Runnable {
+    public void run() {
+    }
+}
+''',
+    'Use.java': '''package zoo;
+
+public class Use {
+    void use(Repo<String> repo, Runnable task) {
+        repo.save("x");
+        task.run();
+    }
+
+    void alone() {
+    }
+}
+''',
+}
+for name, text in sources.items():
+    (project / 'src/zoo' / name).write_text(text)
+uri = lambda name: (project / 'src/zoo' / name).as_uri()
+
+log = (work / 'stderr.log').open('w')
+proc = subprocess.Popen(['java', '-Declipse.application=org.eclipse.jdt.ls.core.id1', '-Dosgi.bundles.defaultStartLevel=4', '-Declipse.product=org.eclipse.jdt.ls.core.product', '-Xmx1G', '--add-modules=ALL-SYSTEM', '--add-opens', 'java.base/java.util=ALL-UNNAMED', '--add-opens', 'java.base/java.lang=ALL-UNNAMED', '-jar', str(next((home / 'plugins').glob('org.eclipse.equinox.launcher_*.jar'))), '-configuration', str(config), '-data', str(work / 'metadata')], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=log)
+messages = queue.Queue()
+lock = threading.Lock()
+
+
+def send(message):
+    data = json.dumps(message).encode()
+    with lock:
+        proc.stdin.write(f'Content-Length: {len(data)}\r\n\r\n'.encode() + data)
+        proc.stdin.flush()
+
+
+def read():
+    while True:
+        headers = {}
+        while True:
+            line = proc.stdout.readline()
+            if not line:
+                return
+            if line == b'\r\n':
+                break
+            k, v = line.decode().split(':', 1)
+            headers[k.lower()] = v.strip()
+        message = json.loads(proc.stdout.read(int(headers['content-length'])))
+        if 'method' in message and 'id' in message:
+            send({'jsonrpc': '2.0', 'id': message['id'], 'result': [] if message['method'] == 'workspace/configuration' else None})
+        else:
+            messages.put(message)
+
+
+threading.Thread(target=read, daemon=True).start()
+seq = 0
+
+
+def request(method, params):
+    global seq
+    seq += 1
+    send({'jsonrpc': '2.0', 'id': seq, 'method': method, 'params': params})
+    deadline = time.monotonic() + 180
+    while time.monotonic() < deadline:
+        msg = messages.get(timeout=max(1, deadline - time.monotonic()))
+        if msg.get('id') == seq:
+            if 'error' in msg:
+                raise RuntimeError(msg['error'])
+            return msg.get('result')
+    raise TimeoutError(method)
+
+
+def position(name, needle):
+    lines = sources[name].splitlines()
+    line = next(i for i, t in enumerate(lines) if needle in t)
+    return line, lines[line].index(needle)
+
+
+def command(name, *args):
+    return request('workspace/executeCommand', {'command': name, 'arguments': list(args)})
+
+
+
+
+def implementations(file, needle):
+    line, col = position(file, needle)
+    found = command('openidea.java.implementations', uri(file), line, col)
+    names = []
+    for loc in found:
+        name = pathlib.Path(urllib.parse.unquote(urllib.parse.urlparse(loc['uri']).path)).name
+        names.append(f"{name}:{loc['range']['start']['line']}")
+    return sorted(names)
+
+
+try:
+    init = request('initialize', {'processId': None, 'rootUri': project.as_uri(), 'workspaceFolders': [{'uri': project.as_uri(), 'name': 'zoo'}], 'capabilities': {}, 'initializationOptions': {'bundles': [str(bundle)], 'settings': {'java': {'import': {'gradle': {'enabled': False}, 'maven': {'enabled': False}}}}}})
+    assert 'openidea.java.implementations' in init['capabilities']['executeCommandProvider']['commands']
+    send({'jsonrpc': '2.0', 'method': 'initialized', 'params': {}})
+    for name, text in sources.items():
+        send({'jsonrpc': '2.0', 'method': 'textDocument/didOpen', 'params': {'textDocument': {'uri': uri(name), 'languageId': 'java', 'version': 1, 'text': text}}})
+    request('java/buildWorkspace', True)
+    cases = {
+        # Classes, abstract ones too; not the sub-interface.
+        ('Repo.java', 'Repo<T>'): ['Base.java:2', 'Numbers.java:2', 'Words.java:2'],
+        # Through the type arguments; not the abstract re-declaration.
+        ('Repo.java', 'save(T'): ['Numbers.java:3', 'Words.java:3'],
+        ('Use.java', 'save("x")'): ['Numbers.java:3', 'Words.java:3'],
+        ('Repo.java', 'name()'): ['Words.java:6'],
+        # A library type's implementations in the sources.
+        ('Use.java', 'Runnable task'): ['Task.java:2'],
+        ('Use.java', 'run();'): ['Task.java:3'],
+        ('Use.java', 'alone()'): [],
+    }
+    failures = []
+    for (file, needle), expected in cases.items():
+        actual = implementations(file, needle)
+        print(f'{file} {needle!r}: {actual}')
+        if actual != expected:
+            failures.append((file, needle, expected, actual))
+    assert not failures, failures
+    print('ok')
+finally:
+    proc.kill()
+    shutil.rmtree(work, ignore_errors=True)