InlineEdit: Add GET /changes/<id>/edit REST endpoint

Add get REST endpoint to read details of change edit. Result is a
EditInfo JSON response or no content when edit doesn't exist for
this change.

Change-Id: I72969cea48b4b1f13154bfa93d403405bec37494

Documentation/rest-api-changes.txt

@@ -1139,6 +1139,61 @@ Administrate Server] capability.
   HTTP/1.1 204 No Content
 ----
 
+[[edit-endpoints]]
+== Change Edit Endpoints
+
+These endpoints are considered to be unstable and can be changed in
+backwards incompatible way any time without notice.
+
+[[get-edit-detail]]
+=== Get Change Edit Details
+--
+'GET /changes/link:#change-id[\{change-id\}]/edit
+--
+
+Retrieves a change edit details.
+
+.Request
+----
+  GET /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/edit HTTP/1.0
+----
+
+As response an link:#edit-info[EditInfo] entity is returned that
+describes the change edit, or "`204 No Content`" when change edit doesn't
+exist for this change. Change edits are stored on special branches and there
+can be max one edit per user per change. Edits aren't tracked in the database.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json;charset=UTF-8
+
+  )]}'
+  {
+    "commit":{
+      "parents":[
+        {
+          "commit":"1eee2c9d8f352483781e772f35dc586a69ff5646",
+        }
+      ],
+      "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 ..."
+    },
+  }
+----
 
 [[reviewer-endpoints]]
 == Reviewer Endpoints
@@ -3589,6 +3644,17 @@ The `WebLinkInfo` entity describes a link to an external site.
 |`url`     |The link URL.
 |======================
 
+[[edit-info]]
+=== EditInfo
+The `EditInfo` entity contains information about a change edit.
+
+[options="header",width="50%",cols="1,^1,5"]
+|===========================
+|Field Name    ||Description
+|`commit`      ||The commit of change edit as
+link:#commit-info[CommitInfo] entity.
+|===========================
+
 GERRIT
 ------
 Part of link:index.html[Gerrit Code Review]

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -27,9 +27,10 @@ import com.google.common.base.Optional;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.AcceptanceTestRequestScope;
-import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.acceptance.RestSession;
+import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.reviewdb.client.Change;
@@ -45,6 +46,7 @@ import com.google.gwtorm.server.SchemaFactory;
 import com.google.inject.Inject;
 import com.google.inject.util.Providers;
 
+import org.apache.http.HttpStatus;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
@@ -56,10 +58,10 @@ import org.junit.Before;
 import org.junit.Test;
 
 import java.io.ByteArrayOutputStream;
+import java.io.IOException;
 import java.util.Date;
 import java.util.concurrent.atomic.AtomicLong;
 
-@NoHttpd
 public class ChangeEditIT extends AbstractDaemonTest {
 
   private final static String FILE_NAME = "foo";
@@ -211,6 +213,32 @@ public class ChangeEditIT extends AbstractDaemonTest {
     assertFalse(edit.isPresent());
   }
 
+  @Test
+  public void retrieveEdit() throws Exception {
+    RestResponse r = session.get(url());
+    assertEquals(HttpStatus.SC_NO_CONTENT, r.getStatusCode());
+    assertEquals(RefUpdate.Result.NEW,
+        modifier.createEdit(
+            change,
+            ps));
+    Optional<ChangeEdit> edit = editUtil.byChange(change);
+    assertEquals(RefUpdate.Result.FORCED,
+        modifier.modifyFile(
+            edit.get(),
+            FILE_NAME,
+            CONTENT_NEW));
+    edit = editUtil.byChange(change);
+    EditInfo info = toEditInfo();
+    assertEquals(edit.get().getRevision().get(), info.commit.commit);
+    assertEquals(1, info.commit.parents.size());
+
+    edit = editUtil.byChange(change);
+    editUtil.delete(edit.get());
+
+    r = session.get(url());
+    assertEquals(HttpStatus.SC_NO_CONTENT, r.getStatusCode());
+  }
+
   @Test
   public void deleteExistingFile() throws Exception {
     assertEquals(RefUpdate.Result.NEW,
@@ -410,4 +438,16 @@ public class ChangeEditIT extends AbstractDaemonTest {
     content.writeTo(os);
     return os.toByteArray();
   }
+
+  private String url() {
+    return "/changes/"
+        + change.getChangeId()
+        + "/edit";
+  }
+
+  private EditInfo toEditInfo() throws IOException {
+    RestResponse r = session.get(url());
+    assertEquals(HttpStatus.SC_OK, r.getStatusCode());
+    return newGson().fromJson(r.getReader(), EditInfo.class);
+  }
 }

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/EditInfo.java

@@ -0,0 +1,19 @@
+// 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.extensions.common;
+
+public class EditInfo {
+  public CommitInfo commit;
+}

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeInfo.java

@@ -204,6 +204,14 @@ public class ChangeInfo extends JavaScriptObject {
     }
   }
 
+  public static class EditInfo extends JavaScriptObject {
+    public final native String name() /*-{ return this.name; }-*/;
+    public final native CommitInfo commit() /*-{ return this.commit; }-*/;
+
+    protected EditInfo() {
+    }
+  }
+
   public static class RevisionInfo extends JavaScriptObject {
     public final native int _number() /*-{ return this._number; }-*/;
     public final native String name() /*-{ return this.name; }-*/;

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeEdits.java

@@ -14,21 +14,37 @@
 
 package com.google.gerrit.server.change;
 
+import com.google.common.base.Optional;
+import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.AuthException;
 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.Response;
+import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.server.edit.ChangeEdit;
+import com.google.gerrit.server.edit.ChangeEditJson;
+import com.google.gerrit.server.edit.ChangeEditUtil;
+import com.google.gerrit.server.project.InvalidChangeOperationException;
+import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
+import java.io.IOException;
+
 @Singleton
 class ChangeEdits implements
     ChildCollection<ChangeResource, ChangeEditResource> {
   private final DynamicMap<RestView<ChangeEditResource>> views;
+  private final Detail detail;
 
   @Inject
-  ChangeEdits(DynamicMap<RestView<ChangeEditResource>> views) {
+  ChangeEdits(DynamicMap<RestView<ChangeEditResource>> views,
+      Detail detail) {
     this.views = views;
+    this.detail = detail;
   }
 
   @Override
@@ -38,11 +54,35 @@ class ChangeEdits implements
 
   @Override
   public RestView<ChangeResource> list() {
-    throw new IllegalStateException("not yet implemented");
+    return detail;
   }
 
   @Override
   public ChangeEditResource parse(ChangeResource change, IdString id) {
     throw new IllegalStateException("not yet implemented");
   }
+
+  @Singleton
+  static class Detail implements RestReadView<ChangeResource> {
+    private final ChangeEditUtil editUtil;
+    private final ChangeEditJson editJson;
+
+    @Inject
+    Detail(ChangeEditJson editJson,
+        ChangeEditUtil editUtil) {
+      this.editJson = editJson;
+      this.editUtil = editUtil;
+    }
+
+    @Override
+    public Response<EditInfo> apply(ChangeResource rsrc) throws AuthException,
+        IOException, NoSuchChangeException, InvalidChangeOperationException,
+        ResourceNotFoundException {
+      Optional<ChangeEdit> edit = editUtil.byChange(rsrc.getChange());
+      if (edit.isPresent()) {
+        return Response.ok(editJson.toEditInfo(edit.get()));
+      }
+      return Response.none();
+    }
+  }
 }

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

@@ -101,6 +101,8 @@ public class Module extends RestApiModule {
     get(FILE_KIND, "content").to(GetContent.class);
     get(FILE_KIND, "diff").to(GetDiff.class);
 
+    child(CHANGE_KIND, "edit").to(ChangeEdits.class);
+
     install(new FactoryModule() {
       @Override
       protected void configure() {

gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditJson.java

@@ -0,0 +1,51 @@
+// 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.edit;
+
+import com.google.common.collect.Lists;
+import com.google.gerrit.extensions.common.CommitInfo;
+import com.google.gerrit.extensions.common.EditInfo;
+import com.google.gerrit.server.CommonConverters;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.revwalk.RevCommit;
+
+import java.io.IOException;
+
+@Singleton
+public class ChangeEditJson {
+  public EditInfo toEditInfo(ChangeEdit edit) throws IOException {
+    EditInfo out = new EditInfo();
+    out.commit = fillCommit(edit.getEditCommit());
+    return out;
+  }
+
+  private static CommitInfo fillCommit(RevCommit editCommit) throws IOException {
+    CommitInfo commit = new CommitInfo();
+    commit.commit = editCommit.toObjectId().getName();
+    commit.parents = Lists.newArrayListWithCapacity(1);
+    commit.author = CommonConverters.toGitPerson(editCommit.getAuthorIdent());
+    commit.committer = CommonConverters.toGitPerson(
+        editCommit.getCommitterIdent());
+    commit.subject = editCommit.getShortMessage();
+    commit.message = editCommit.getFullMessage();
+
+    CommitInfo i = new CommitInfo();
+    i.commit = editCommit.getParent(0).toObjectId().getName();
+    commit.parents.add(i);
+
+    return commit;
+  }
+}