Add REST endpoint to get an arbitrary commit from a project

Bug: issue 2604
Change-Id: I138e60c5291d61c379e947ea26b0fd9d5555c743
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/rest-api-projects.txt

@@ -972,6 +972,59 @@ describes the child project.
   }
 ----
 
+[[commit-endpoints]]
+== Commit Endpoints
+
+[[get-commit]]
+=== Get Commit
+--
+'GET /projects/link:#project-name[\{project-name\}]/commits/link:#commit-id[\{commit-id\}]'
+--
+
+Retrieves a commit of a project.
+
+The commit must be visible to the caller.
+
+.Request
+----
+  GET /projects/work%2Fmy-project/commits/a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96 HTTP/1.0
+----
+
+As response a link:rest-api-changes.html#commit-info[CommitInfo] entity
+is returned that describes the commit.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json;charset=UTF-8
+
+  )]}'
+  {
+    "commit": "184ebe53805e102605d11f6b143486d15c23a09c",
+    "parents": [
+      {
+        "commit": "1eee2c9d8f352483781e772f35dc586a69ff5646",
+        "subject": "Migrate contributor agreements to All-Projects."
+      }
+    ],
+    "author": {
+      "name": "Shawn O. Pearce",
+      "email": "sop@google.com",
+      "date": "2012-04-24 18:08:08.000000000",
+      "tz": -420
+    },
+    "committer": {
+      "name": "Shawn O. Pearce",
+      "email": "sop@google.com",
+      "date": "2012-04-24 18:08:08.000000000",
+      "tz": -420
+    },
+    "subject": "Use an EventBus to manage star icons",
+    "message": "Use an EventBus to manage star icons\n\nImage widgets that need to ..."
+  }
+----
+
 [[dashboard-endpoints]]
 == Dashboard Endpoints
 
@@ -1199,6 +1252,10 @@ requests.
 The name of a branch or `HEAD`. The prefix `refs/heads/` can be
 omitted.
 
+[[commit-id]]
+=== \{commit-id\}
+Commit ID.
+
 [[dashboard-id]]
 === \{dashboard-id\}
 The ID of a dashboard in the format '<ref>:<path>'.

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/rest/project/GetCommitIT.java

@@ -0,0 +1,111 @@
+// Copyright (C) 2014 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.acceptance.rest.project;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.common.data.Permission;
+import com.google.gerrit.extensions.common.CommitInfo;
+import com.google.gerrit.extensions.restapi.IdString;
+import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.git.MetaDataUpdate;
+import com.google.gerrit.server.git.ProjectConfig;
+import com.google.gerrit.server.project.ListBranches.BranchInfo;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.inject.Inject;
+
+import org.apache.http.HttpStatus;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class GetCommitIT extends AbstractDaemonTest {
+
+  @Inject
+  private ProjectCache projectCache;
+
+  @Inject
+  private AllProjectsName allProjects;
+
+  @Inject
+  private MetaDataUpdate.Server metaDataUpdateFactory;
+
+  @Test
+  public void getCommit() throws IOException {
+    RestResponse r =
+        adminSession.get("/projects/" + project.get() + "/branches/"
+            + IdString.fromDecoded(RefNames.REFS_CONFIG).encoded());
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    BranchInfo branchInfo =
+        newGson().fromJson(r.getReader(), BranchInfo.class);
+    r.consume();
+
+    r = adminSession.get("/projects/" + project.get() + "/commits/"
+        + branchInfo.revision);
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    CommitInfo commitInfo =
+        newGson().fromJson(r.getReader(), CommitInfo.class);
+    assertEquals(branchInfo.revision, commitInfo.commit);
+    assertEquals("Created project", commitInfo.subject);
+    assertEquals("Created project\n", commitInfo.message);
+    assertNotNull(commitInfo.author);
+    assertEquals("Administrator", commitInfo.author.name);
+    assertNotNull(commitInfo.committer);
+    assertEquals("Gerrit Code Review", commitInfo.committer.name);
+    assertTrue(commitInfo.parents.isEmpty());
+  }
+
+  @Test
+  public void getNonExistingCommit_NotFound() throws IOException {
+    RestResponse r = adminSession.get("/projects/" + project.get() + "/commits/"
+        + ObjectId.zeroId().name());
+    assertEquals(HttpStatus.SC_NOT_FOUND, r.getStatusCode());
+  }
+
+  @Test
+  public void getNonVisibleCommit_NotFound() throws IOException {
+    RestResponse r =
+        adminSession.get("/projects/" + project.get() + "/branches/"
+            + IdString.fromDecoded(RefNames.REFS_CONFIG).encoded());
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    BranchInfo branchInfo =
+        newGson().fromJson(r.getReader(), BranchInfo.class);
+    r.consume();
+
+    ProjectConfig cfg = projectCache.checkedGet(allProjects).getConfig();
+    cfg.getAccessSection("refs/*", false).removePermission(Permission.READ);
+    saveProjectConfig(cfg);
+    projectCache.evict(cfg.getProject());
+
+    r = adminSession.get("/projects/" + project.get() + "/commits/"
+        + branchInfo.revision);
+    assertEquals(HttpStatus.SC_NOT_FOUND, r.getStatusCode());
+  }
+
+  private void saveProjectConfig(ProjectConfig cfg) throws IOException {
+    MetaDataUpdate md = metaDataUpdateFactory.create(allProjects);
+    try {
+      cfg.commit(md);
+    } finally {
+      md.close();
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/CommitResource.java

@@ -0,0 +1,36 @@
+// Copyright (C) 2014 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.project;
+
+import com.google.gerrit.extensions.restapi.RestView;
+import com.google.inject.TypeLiteral;
+
+import org.eclipse.jgit.revwalk.RevCommit;
+
+public class CommitResource extends ProjectResource {
+  public static final TypeLiteral<RestView<CommitResource>> COMMIT_KIND =
+      new TypeLiteral<RestView<CommitResource>>() {};
+
+  private final RevCommit commit;
+
+  public CommitResource(ProjectControl control, RevCommit commit) {
+    super(control);
+    this.commit = commit;
+  }
+
+  public RevCommit getCommit() {
+    return commit;
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/CommitsCollection.java

@@ -0,0 +1,89 @@
+// Copyright (C) 2014 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.project;
+
+import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+import java.io.IOException;
+
+@Singleton
+public class CommitsCollection implements
+    ChildCollection<ProjectResource, CommitResource> {
+  private final DynamicMap<RestView<CommitResource>> views;
+  private final GitRepositoryManager repoManager;
+
+  @Inject
+  public CommitsCollection(DynamicMap<RestView<CommitResource>> views,
+      GitRepositoryManager repoManager) {
+    this.views = views;
+    this.repoManager = repoManager;
+  }
+
+  @Override
+  public RestView<ProjectResource> list() throws ResourceNotFoundException {
+    throw new ResourceNotFoundException();
+  }
+
+  @Override
+  public CommitResource parse(ProjectResource parent, IdString id)
+      throws ResourceNotFoundException, IOException {
+    ObjectId objectId;
+    try {
+      objectId = ObjectId.fromString(id.get());
+    } catch (IllegalArgumentException e) {
+      throw new ResourceNotFoundException(id);
+    }
+
+    Repository repo = repoManager.openRepository(parent.getNameKey());
+    try {
+      RevWalk rw = new RevWalk(repo);
+      try {
+        RevCommit commit = rw.parseCommit(objectId);
+        if (!parent.getControl().canReadCommit(rw, commit)) {
+          throw new ResourceNotFoundException(id);
+        }
+        for (int i = 0; i < commit.getParentCount(); i++) {
+          rw.parseCommit(commit.getParent(i));
+        }
+        return new CommitResource(parent.getControl(), commit);
+      } catch (MissingObjectException | IncorrectObjectTypeException e) {
+        throw new ResourceNotFoundException(id);
+      } finally {
+        rw.release();
+      }
+    } finally {
+      repo.close();
+    }
+  }
+
+  @Override
+  public DynamicMap<RestView<CommitResource>> views() {
+    return views;
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/GetCommit.java

@@ -0,0 +1,64 @@
+// Copyright (C) 2014 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.project;
+
+import com.google.gerrit.extensions.common.CommitInfo;
+import com.google.gerrit.extensions.common.GitPerson;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.revwalk.RevCommit;
+
+import java.sql.Timestamp;
+import java.util.ArrayList;
+
+@Singleton
+public class GetCommit implements RestReadView<CommitResource> {
+
+  @Override
+  public CommitInfo apply(CommitResource rsrc) {
+    RevCommit c = rsrc.getCommit();
+    CommitInfo info = toCommitInfo(c);
+    return info;
+  }
+
+  private static CommitInfo toCommitInfo(RevCommit commit) {
+    CommitInfo info = new CommitInfo();
+    info.commit = commit.getName();
+    info.author = toGitPerson(commit.getAuthorIdent());
+    info.committer = toGitPerson(commit.getCommitterIdent());
+    info.subject = commit.getShortMessage();
+    info.message = commit.getFullMessage();
+    info.parents = new ArrayList<>(commit.getParentCount());
+    for (int i = 0; i < commit.getParentCount(); i++) {
+      RevCommit p = commit.getParent(i);
+      CommitInfo parentInfo = new CommitInfo();
+      parentInfo.commit = p.getName();
+      parentInfo.subject = p.getShortMessage();
+      info.parents.add(parentInfo);
+    }
+    return info;
+  }
+
+  private static GitPerson toGitPerson(PersonIdent ident) {
+    GitPerson gp = new GitPerson();
+    gp.name = ident.getName();
+    gp.email = ident.getEmailAddress();
+    gp.date = new Timestamp(ident.getWhen().getTime());
+    gp.tz = ident.getTimeZoneOffset();
+    return gp;
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/project/Module.java

@@ -16,9 +16,10 @@ package com.google.gerrit.server.project;
 
 import static com.google.gerrit.server.project.BranchResource.BRANCH_KIND;
 import static com.google.gerrit.server.project.ChildProjectResource.CHILD_PROJECT_KIND;
+import static com.google.gerrit.server.project.CommitResource.COMMIT_KIND;
 import static com.google.gerrit.server.project.DashboardResource.DASHBOARD_KIND;
-import static com.google.gerrit.server.project.ProjectResource.PROJECT_KIND;
 import static com.google.gerrit.server.project.FileResource.FILE_KIND;
+import static com.google.gerrit.server.project.ProjectResource.PROJECT_KIND;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.RestApiModule;
@@ -35,6 +36,7 @@ public class Module extends RestApiModule {
     DynamicMap.mapOf(binder(), BRANCH_KIND);
     DynamicMap.mapOf(binder(), DASHBOARD_KIND);
     DynamicMap.mapOf(binder(), FILE_KIND);
+    DynamicMap.mapOf(binder(), COMMIT_KIND);
 
     put(PROJECT_KIND).to(PutProject.class);
     get(PROJECT_KIND).to(GetProject.class);
@@ -63,6 +65,9 @@ public class Module extends RestApiModule {
     child(BRANCH_KIND, "files").to(FilesCollection.class);
     get(FILE_KIND, "content").to(GetContent.class);
 
+    child(PROJECT_KIND, "commits").to(CommitsCollection.class);
+    get(COMMIT_KIND).to(GetCommit.class);
+
     child(PROJECT_KIND, "dashboards").to(DashboardsCollection.class);
     get(DASHBOARD_KIND).to(GetDashboard.class);
     put(DASHBOARD_KIND).to(SetDashboard.class);