Add REST endpoint to ban commits

Change-Id: I941f76be00b9bce7f6f6f26925a82efe76fa42b5
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

Documentation/rest-api-projects.txt

@@ -789,6 +789,57 @@ The response is the streamed output of the garbage collection.
   done.
 ----
 
+[[ban-commit]]
+=== Ban Commit
+--
+'PUT /projects/link:#project-name[\{project-name\}]/ban'
+--
+
+Marks commits as banned for the project. If a commit is banned Gerrit
+rejects every push that includes this commit with
+link:error-contains-banned-commit.html[contains banned commit ...].
+
+[NOTE]
+This REST endpoint only marks the commits as banned, but it does not
+remove the commits from the history of any central branch. This needs
+to be done manually.
+
+The commits to be banned must be specified in the request body as a
+link:#ban-input[BanInput] entity.
+
+The caller must be project owner.
+
+.Request
+----
+  PUT /projects/plugins%2Freplication/ban HTTP/1.0
+  Content-Type: application/json;charset=UTF-8
+
+  {
+    "commits": [
+      "a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96",
+      "cf5b56541f84b8b57e16810b18daca9c3adc377b"
+    ],
+    "reason": "Violates IP"
+  }
+----
+
+As response a link:#ban-result-info[BanResultInfo] entity is returned.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json;charset=UTF-8
+
+  )]}'
+  {
+    "newly_banned": [
+      "a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96",
+      "cf5b56541f84b8b57e16810b18daca9c3adc377b"
+    ]
+  }
+----
+
 [[branch-endpoints]]
 == Branch Endpoints
 
@@ -1492,6 +1543,30 @@ The `BranchInfo` entity contains information about a branch.
 Whether the calling user can delete this branch.
 |=========================
 
+[[ban-input]]
+=== BanInput
+The `BanInput` entity contains information for banning commits in a
+project.
+
+[options="header",width="50%",cols="1,^2,4"]
+|=======================
+|Field Name||Description
+|`commits` ||List of commits to be banned.
+|`reason`  |optional|Reason for banning the commits.
+|=======================
+
+[[ban-result-info]]
+=== BanResultInfo
+The `BanResultInfo` entity describes the result of banning commits.
+
+[options="header",width="50%",cols="1,^2,4"]
+|=============================
+|Field Name      ||Description
+|`newly_banned`  |optional|List of newly banned commits.
+|`already_banned`|optional|List of commits that were already banned.
+|`ignored`       |optional|List of object IDs that were ignored.
+|=============================
+
 [[branch-input]]
 === BranchInput
 The `BranchInput` entity contains information for the creation of

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

@@ -0,0 +1,82 @@
+// 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 com.google.gerrit.acceptance.GitUtil.add;
+import static com.google.gerrit.acceptance.GitUtil.createCommit;
+import static com.google.gerrit.acceptance.GitUtil.pushHead;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.GitUtil.Commit;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.server.project.BanCommit;
+import com.google.gerrit.server.project.BanCommit.BanResultInfo;
+
+import org.apache.http.HttpStatus;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.transport.PushResult;
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class BanCommitIT extends AbstractDaemonTest {
+
+  @Test
+  public void banCommit() throws IOException, GitAPIException {
+    add(git, "a.txt", "some content");
+    Commit c = createCommit(git, admin.getIdent(), "subject");
+
+    RestResponse r =
+        adminSession.put("/projects/" + project.get() + "/ban/",
+            BanCommit.Input.fromCommits(c.getCommit().getName()));
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    BanResultInfo info = newGson().fromJson(r.getReader(), BanResultInfo.class);
+    assertEquals(c.getCommit().getName(), Iterables.getOnlyElement(info.newlyBanned));
+    assertNull(info.alreadyBanned);
+    assertNull(info.ignored);
+
+    PushResult pushResult = pushHead(git, "refs/heads/master", false);
+    assertTrue(pushResult.getRemoteUpdate("refs/heads/master").getMessage()
+        .startsWith("contains banned commit"));
+  }
+
+  @Test
+  public void banAlreadyBannedCommit() throws IOException, GitAPIException {
+    RestResponse r =
+        adminSession.put("/projects/" + project.get() + "/ban/",
+            BanCommit.Input.fromCommits("a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96"));
+    r.consume();
+
+    r = adminSession.put("/projects/" + project.get() + "/ban/",
+        BanCommit.Input.fromCommits("a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96"));
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    BanResultInfo info = newGson().fromJson(r.getReader(), BanResultInfo.class);
+    assertEquals("a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96", Iterables.getOnlyElement(info.alreadyBanned));
+    assertNull(info.newlyBanned);
+    assertNull(info.ignored);
+  }
+
+  @Test
+  public void banCommit_Forbidden() throws IOException {
+    RestResponse r =
+        userSession.put("/projects/" + project.get() + "/ban/",
+            BanCommit.Input.fromCommits("a8a477efffbbf3b44169bb9a1d3a334cbbd9aa96"));
+    assertEquals(HttpStatus.SC_FORBIDDEN, r.getStatusCode());
+  }
+}

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

@@ -0,0 +1,106 @@
+// 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.common.base.Function;
+import com.google.common.collect.Lists;
+import com.google.gerrit.common.errors.PermissionDeniedException;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.server.git.BanCommitResult;
+import com.google.gerrit.server.git.MergeException;
+import com.google.gerrit.server.project.BanCommit.Input;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
+import org.eclipse.jgit.lib.ObjectId;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+@Singleton
+public class BanCommit implements RestModifyView<ProjectResource, Input> {
+  public static class Input {
+    public List<String> commits;
+    public String reason;
+
+    public static Input fromCommits(String firstCommit, String... moreCommits) {
+      return fromCommits(Lists.asList(firstCommit, moreCommits));
+    }
+
+    public static Input fromCommits(List<String> commits) {
+      Input in = new Input();
+      in.commits = commits;
+      return in;
+    }
+  }
+
+  @Inject
+  private com.google.gerrit.server.git.BanCommit banCommit;
+
+  @Override
+  public BanResultInfo apply(ProjectResource rsrc, Input input)
+      throws UnprocessableEntityException, AuthException,
+      ResourceConflictException, IOException, InterruptedException {
+    BanResultInfo r = new BanResultInfo();
+    if (input != null && input.commits != null && !input.commits.isEmpty()) {
+      List<ObjectId> commitsToBan = new ArrayList<>(input.commits.size());
+      for (String c : input.commits) {
+        try {
+          commitsToBan.add(ObjectId.fromString(c));
+        } catch (IllegalArgumentException e) {
+          throw new UnprocessableEntityException(e.getMessage());
+        }
+      }
+
+      try {
+        BanCommitResult result =
+            banCommit.ban(rsrc.getControl(), commitsToBan, input.reason);
+        r.newlyBanned = transformCommits(result.getNewlyBannedCommits());
+        r.alreadyBanned = transformCommits(result.getAlreadyBannedCommits());
+        r.ignored = transformCommits(result.getIgnoredObjectIds());
+      } catch (PermissionDeniedException e) {
+        throw new AuthException(e.getMessage());
+      } catch (MergeException | ConcurrentRefUpdateException e) {
+        throw new ResourceConflictException(e.getMessage(), e);
+      }
+    }
+    return r;
+  }
+
+  private static List<String> transformCommits(List<ObjectId> commits) {
+    if (commits == null || commits.isEmpty()) {
+      return null;
+    }
+
+    return Lists.transform(commits,
+        new Function<ObjectId, String>() {
+          @Override
+          public String apply(ObjectId id) {
+            return id.getName();
+          }
+        });
+  }
+
+  public static class BanResultInfo {
+    public List<String> newlyBanned;
+    public List<String> alreadyBanned;
+    public List<String> ignored;
+  }
+}

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

@@ -53,6 +53,8 @@ public class Module extends RestApiModule {
     get(PROJECT_KIND, "HEAD").to(GetHead.class);
     put(PROJECT_KIND, "HEAD").to(SetHead.class);
 
+    put(PROJECT_KIND, "ban").to(BanCommit.class);
+
     get(PROJECT_KIND, "statistics.git").to(GetStatistics.class);
     post(PROJECT_KIND, "gc").to(GarbageCollect.class);