Revision API: Add method to get patch

Patch is returned as BinaryResult.

Change-Id: Ia92f00d7332d0f6d91744ffbcc6098824bdedd58

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/PushOneCommit.java

@@ -47,6 +47,23 @@ public class PushOneCommit {
   public static final String SUBJECT = "test commit";
   public static final String FILE_NAME = "a.txt";
   public static final String FILE_CONTENT = "some content";
+  public static final String PATCH =
+      "From %s Mon Sep 17 00:00:00 2001\n" +
+      "From: Administrator <admin@example.com>\n" +
+      "Date: %s\n" +
+      "Subject: [PATCH] test commit\n" +
+      "\n" +
+      "Change-Id: %s\n" +
+      "---\n" +
+      "\n" +
+      "diff --git a/a.txt b/a.txt\n" +
+      "new file mode 100644\n" +
+      "index 0000000..f0eec86\n" +
+      "--- /dev/null\n" +
+      "+++ b/a.txt\n" +
+      "@@ -0,0 +1 @@\n" +
+      "+some content\n" +
+      "\\ No newline at end of file\n";
 
   public interface Factory {
     PushOneCommit create(

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/revision/RevisionIT.java

@@ -17,6 +17,7 @@ package com.google.gerrit.acceptance.api.revision;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.acceptance.PushOneCommit.FILE_CONTENT;
 import static com.google.gerrit.acceptance.PushOneCommit.FILE_NAME;
+import static com.google.gerrit.acceptance.PushOneCommit.PATCH;
 import static org.eclipse.jgit.lib.Constants.HEAD;
 
 import com.google.common.base.Predicate;
@@ -40,6 +41,7 @@ import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.DiffInfo;
 import com.google.gerrit.extensions.common.MergeableInfo;
+import com.google.gerrit.extensions.common.RevisionInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -52,6 +54,8 @@ import org.junit.Test;
 
 import java.io.ByteArrayOutputStream;
 import java.nio.charset.StandardCharsets;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -540,6 +544,25 @@ public class RevisionIT extends AbstractDaemonTest {
       .isEqualTo(in.message);
   }
 
+  @Test
+  public void patch() throws Exception {
+    PushOneCommit.Result r = createChange();
+    ChangeApi changeApi = gApi.changes()
+        .id(r.getChangeId());
+    BinaryResult bin = changeApi
+        .revision(r.getCommit().name())
+        .patch();
+    ByteArrayOutputStream os = new ByteArrayOutputStream();
+    bin.writeTo(os);
+    String res = new String(os.toByteArray(), StandardCharsets.UTF_8);
+    DateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z");
+    ChangeInfo change = changeApi.get();
+    RevisionInfo rev = change.revisions.get(change.currentRevision);
+    String date = dateFormat.format(rev.commit.author.date);
+    assertThat(res).isEqualTo(
+        String.format(PATCH, r.getCommitId().name(), date, r.getChangeId()));
+  }
+
   private void merge(PushOneCommit.Result r) throws Exception {
     revision(r).review(ReviewInput.approve());
     revision(r).submit();

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RevisionApi.java

@@ -18,6 +18,7 @@ import com.google.gerrit.extensions.common.ActionInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.common.MergeableInfo;
+import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.NotImplementedException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 
@@ -57,6 +58,11 @@ public interface RevisionApi {
 
   CommentApi comment(String id) throws RestApiException;
 
+  /**
+   * Returns patch of revision.
+   */
+  BinaryResult patch() throws RestApiException;
+
   Map<String, ActionInfo> actions() throws RestApiException;
 
   /**
@@ -179,6 +185,11 @@ public interface RevisionApi {
       throw new NotImplementedException();
     }
 
+    @Override
+    public BinaryResult patch() throws RestApiException {
+      throw new NotImplementedException();
+    }
+
     @Override
     public Map<String, ActionInfo> actions() throws RestApiException {
       throw new NotImplementedException();

gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java

@@ -31,6 +31,7 @@ import com.google.gerrit.extensions.common.ActionInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.common.MergeableInfo;
+import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
@@ -41,6 +42,7 @@ import com.google.gerrit.server.change.DeleteDraftPatchSet;
 import com.google.gerrit.server.change.DraftComments;
 import com.google.gerrit.server.change.FileResource;
 import com.google.gerrit.server.change.Files;
+import com.google.gerrit.server.change.GetPatch;
 import com.google.gerrit.server.change.GetRevisionActions;
 import com.google.gerrit.server.change.ListRevisionComments;
 import com.google.gerrit.server.change.ListRevisionDrafts;
@@ -79,6 +81,7 @@ class RevisionApiImpl implements RevisionApi {
   private final RevisionResource revision;
   private final Provider<Files> files;
   private final Provider<Files.ListFiles> listFiles;
+  private final Provider<GetPatch> getPatch;
   private final Provider<PostReview> review;
   private final Provider<Mergeable> mergeable;
   private final FileApiImpl.Factory fileApi;
@@ -103,6 +106,7 @@ class RevisionApiImpl implements RevisionApi {
       Reviewed.DeleteReviewed deleteReviewed,
       Provider<Files> files,
       Provider<Files.ListFiles> listFiles,
+      Provider<GetPatch> getPatch,
       Provider<PostReview> review,
       Provider<Mergeable> mergeable,
       FileApiImpl.Factory fileApi,
@@ -127,6 +131,7 @@ class RevisionApiImpl implements RevisionApi {
     this.putReviewed = putReviewed;
     this.deleteReviewed = deleteReviewed;
     this.listFiles = listFiles;
+    this.getPatch = getPatch;
     this.mergeable = mergeable;
     this.fileApi = fileApi;
     this.listComments = listComments;
@@ -356,6 +361,15 @@ class RevisionApiImpl implements RevisionApi {
     }
   }
 
+  @Override
+  public BinaryResult patch() throws RestApiException {
+    try {
+      return getPatch.get().apply(revision);
+    } catch (IOException e) {
+      throw new RestApiException("Cannot get patch", e);
+    }
+  }
+
   @Override
   public Map<String, ActionInfo> actions() throws RestApiException {
     return revisionActions.apply(revision).value();