1 files changed, 200 insertions, 0 deletions
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/patch/PatchListCacheImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
new file mode 100644
index 0000000000..71342ff6f4
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
@@ -0,0 +1,200 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch;
+
+import static com.google.gerrit.common.data.PatchScriptSettings.Whitespace.IGNORE_NONE;
+
+import com.google.gerrit.common.data.PatchScriptSettings.Whitespace;
+import com.google.gerrit.reviewdb.Change;
+import com.google.gerrit.reviewdb.PatchSet;
+import com.google.gerrit.reviewdb.Project;
+import com.google.gerrit.server.cache.Cache;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gerrit.server.cache.EvictionPolicy;
+import com.google.gerrit.server.cache.SelfPopulatingCache;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.Singleton;
+import com.google.inject.TypeLiteral;
+import com.google.inject.name.Named;
+
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectWriter;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Provides a cached list of {@link PatchListEntry}. */
+@Singleton
+public class PatchListCacheImpl implements PatchListCache {
+  private static final String CACHE_NAME = "diff";
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        final TypeLiteral<Cache<PatchListKey, PatchList>> type =
+            new TypeLiteral<Cache<PatchListKey, PatchList>>() {};
+        disk(type, CACHE_NAME) //
+            .memoryLimit(128) // very large items, cache only a few
+            .evictionPolicy(EvictionPolicy.LRU) // prefer most recent
+        ;
+        bind(PatchListCacheImpl.class);
+        bind(PatchListCache.class).to(PatchListCacheImpl.class);
+      }
+    };
+  }
+
+  private final GitRepositoryManager repoManager;
+  private final SelfPopulatingCache<PatchListKey, PatchList> self;
+
+  @Inject
+  PatchListCacheImpl(final GitRepositoryManager grm,
+      @Named(CACHE_NAME) final Cache<PatchListKey, PatchList> raw) {
+    repoManager = grm;
+    self = new SelfPopulatingCache<PatchListKey, PatchList>(raw) {
+      @Override
+      protected PatchList createEntry(final PatchListKey key) throws Exception {
+        return compute(key);
+      }
+    };
+  }
+
+  public PatchList get(final PatchListKey key) {
+    return self.get(key);
+  }
+
+  public PatchList get(final Change change, final PatchSet patchSet) {
+    return get(change, patchSet, IGNORE_NONE);
+  }
+
+  public PatchList get(final Change change, final PatchSet patchSet,
+      final Whitespace whitespace) {
+    final Project.NameKey projectKey = change.getProject();
+    final ObjectId a = null;
+    final ObjectId b = ObjectId.fromString(patchSet.getRevision().get());
+    return get(new PatchListKey(projectKey, a, b, whitespace));
+  }
+
+  private PatchList compute(final PatchListKey key)
+      throws MissingObjectException, IncorrectObjectTypeException, IOException {
+    final Repository repo = repoManager.openRepository(key.projectKey.get());
+    try {
+      return readPatchList(key, repo);
+    } finally {
+      repo.close();
+    }
+  }
+
+  private PatchList readPatchList(final PatchListKey key, final Repository repo)
+      throws IOException {
+    final RevCommit b = new RevWalk(repo).parseCommit(key.getNewId());
+    final AnyObjectId a = aFor(key, repo, b);
+
+    final List<String> args = new ArrayList<String>();
+    args.add("git");
+    args.add("--git-dir=.");
+    args.add("diff-tree");
+    args.add("-M");
+    switch (key.getWhitespace()) {
+      case IGNORE_NONE:
+        break;
+      case IGNORE_SPACE_AT_EOL:
+        args.add("--ignore-space-at-eol");
+        break;
+      case IGNORE_SPACE_CHANGE:
+        args.add("--ignore-space-change");
+        break;
+      case IGNORE_ALL_SPACE:
+        args.add("--ignore-all-space");
+        break;
+      default:
+        throw new IOException("Unsupported whitespace " + key.getWhitespace());
+    }
+    if (a == null /* want combined diff */) {
+      args.add("--cc");
+      args.add(b.name());
+    } else {
+      args.add("--unified=1");
+      args.add(a.name());
+      args.add(b.name());
+    }
+
+    final org.eclipse.jgit.patch.Patch p = new org.eclipse.jgit.patch.Patch();
+    final Process diffProcess = exec(repo, args);
+    try {
+      diffProcess.getOutputStream().close();
+      diffProcess.getErrorStream().close();
+
+      final InputStream in = diffProcess.getInputStream();
+      try {
+        p.parse(in);
+      } finally {
+        in.close();
+      }
+    } finally {
+      try {
+        final int rc = diffProcess.waitFor();
+        if (rc != 0) {
+          throw new IOException("git diff-tree exited abnormally: " + rc);
+        }
+      } catch (InterruptedException ie) {
+      }
+    }
+
+    final int cnt = p.getFiles().size();
+    final PatchListEntry[] entries = new PatchListEntry[cnt];
+    for (int i = 0; i < cnt; i++) {
+      entries[i] = new PatchListEntry(p.getFiles().get(i));
+    }
+    return new PatchList(a, b, entries);
+  }
+
+  private static AnyObjectId aFor(final PatchListKey key,
+      final Repository repo, final RevCommit b) throws IOException {
+    if (key.getOldId() != null) {
+      return key.getOldId();
+    }
+
+    switch (b.getParentCount()) {
+      case 0:
+        return emptyTree(repo);
+      case 1:
+        return b.getParent(0);
+      default:
+        // merge commit, return null to force combined diff behavior
+        return null;
+    }
+  }
+
+  private static Process exec(final Repository repo, final List<String> args)
+      throws IOException {
+    final String[] argv = args.toArray(new String[args.size()]);
+    return Runtime.getRuntime().exec(argv, null, repo.getDirectory());
+  }
+
+  private static ObjectId emptyTree(final Repository repo) throws IOException {
+    return new ObjectWriter(repo).writeCanonicalTree(new byte[0]);
+  }
+}