Store ChangeMessage in body of commit message

Taught ChangeUpdate how to write out the ChangeMessage into
the message. Also taught ChangeNotes how to parse the
ChangeMessage out of the commit message.

Change-Id: I563eabbd848364150fdf8a5c4af5a2e1562aaefe

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java

@@ -58,8 +58,10 @@ import org.eclipse.jgit.revwalk.FooterKey;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.util.RawParseUtils;
+import org.eclipse.jgit.util.StringUtils;
 
 import java.io.IOException;
+import java.nio.charset.Charset;
 import java.sql.Timestamp;
 import java.util.Collection;
 import java.util.Collections;
@@ -102,6 +104,7 @@ public class ChangeNotes extends VersionedMetaData {
     private final Map<Account.Id, ReviewerState> reviewers;
     private final List<SubmitRecord> submitRecords;
     private Change.Status status;
+    private List<String> changeMessages;
 
     private Parser(Change.Id changeId, ObjectId tip, RevWalk walk) {
       this.changeId = changeId;
@@ -110,6 +113,7 @@ public class ChangeNotes extends VersionedMetaData {
       approvals = Maps.newHashMap();
       reviewers = Maps.newLinkedHashMap();
       submitRecords = Lists.newArrayListWithExpectedSize(1);
+      changeMessages = Lists.newArrayList();
     }
 
     private void parseAll() throws ConfigInvalidException, IOException {
@@ -142,6 +146,8 @@ public class ChangeNotes extends VersionedMetaData {
       }
       PatchSet.Id psId = parsePatchSetId(commit);
       Account.Id accountId = parseIdent(commit);
+      parseChangeMessage(commit);
+
 
       if (submitRecords.isEmpty()) {
         // Only parse the most recent set of submit records; any older ones are
@@ -189,6 +195,56 @@ public class ChangeNotes extends VersionedMetaData {
       return new PatchSet.Id(changeId, psId);
     }
 
+    private void parseChangeMessage(RevCommit commit) {
+      byte[] raw = commit.getRawBuffer();
+      int size = raw.length;
+      Charset enc = RawParseUtils.parseEncoding(raw);
+
+      int subjectStart = RawParseUtils.commitMessage(raw, 0);
+      if (subjectStart < 0 || subjectStart >= size) {
+        return;
+      }
+
+      int subjectEnd = RawParseUtils.endOfParagraph(raw, subjectStart);
+      if (subjectEnd == size) {
+        return;
+      }
+
+      int changeMessageStart;
+
+      if (raw[subjectEnd] == '\n') {
+        changeMessageStart = subjectEnd + 2; //\n\n ends paragraph
+      } else if (raw[subjectEnd] == '\r') {
+        changeMessageStart = subjectEnd + 4; //\r\n\r\n ends paragraph
+      } else {
+        return;
+      }
+
+      int ptr = size - 1;
+      int changeMessageEnd = -1;
+      while(ptr > changeMessageStart) {
+        ptr = RawParseUtils.prevLF(raw, ptr, '\r');
+        if (ptr == -1) {
+          break;
+        }
+        if (raw[ptr] == '\n') {
+          changeMessageEnd = ptr - 1;
+          break;
+        } else if (raw[ptr] == '\r') {
+          changeMessageEnd = ptr - 3;
+          break;
+        }
+      }
+
+      if (ptr <= changeMessageStart) {
+        return;
+      }
+
+      String changeMessage = RawParseUtils.decode(enc, raw,
+          changeMessageStart, changeMessageEnd + 1);
+      changeMessages.add(changeMessage);
+    }
+
     private void parseApproval(PatchSet.Id psId, Account.Id accountId,
         RevCommit commit, String line) throws ConfigInvalidException {
       Table<Account.Id, String, Optional<PatchSetApproval>> curr =
@@ -353,6 +409,7 @@ public class ChangeNotes extends VersionedMetaData {
   private ImmutableListMultimap<PatchSet.Id, PatchSetApproval> approvals;
   private ImmutableSetMultimap<ReviewerState, Account.Id> reviewers;
   private ImmutableList<SubmitRecord> submitRecords;
+  private ImmutableList<String> changeMessages;
 
   @VisibleForTesting
   ChangeNotes(GitRepositoryManager repoManager, Change change) {
@@ -405,6 +462,14 @@ public class ChangeNotes extends VersionedMetaData {
     return submitRecords;
   }
 
+  /**
+   * @return change messages in reverse chronological order.
+   */
+  public ImmutableList<String> getChangeMessages() {
+    return changeMessages;
+
+  }
+
   @Override
   protected String getRefName() {
     return ChangeNoteUtil.changeRefName(change.getId());
@@ -435,6 +500,7 @@ public class ChangeNotes extends VersionedMetaData {
       }
       this.reviewers = reviewers.build();
       submitRecords = ImmutableList.copyOf(parser.submitRecords);
+      changeMessages = ImmutableList.copyOf(parser.changeMessages);
     } finally {
       walk.release();
     }
@@ -444,6 +510,7 @@ public class ChangeNotes extends VersionedMetaData {
     approvals = ImmutableListMultimap.of();
     reviewers = ImmutableSetMultimap.of();
     submitRecords = ImmutableList.of();
+    changeMessages = ImmutableList.of();
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java

@@ -88,6 +88,7 @@ public class ChangeUpdate extends VersionedMetaData {
   private String subject;
   private PatchSet.Id psId;
   private List<SubmitRecord> submitRecords;
+  private String changeMessage;
 
   @AssistedInject
   private ChangeUpdate(
@@ -186,6 +187,10 @@ public class ChangeUpdate extends VersionedMetaData {
     this.psId = psId;
   }
 
+  public void setChangeMessage(String changeMessage) {
+    this.changeMessage = changeMessage;
+  }
+
   public void putReviewer(Account.Id reviewer, ReviewerState type) {
     checkArgument(type != ReviewerState.REMOVED, "invalid ReviewerType");
     reviewers.put(reviewer, type);
@@ -297,6 +302,13 @@ public class ChangeUpdate extends VersionedMetaData {
       msg.append("Update patch set ").append(ps);
     }
     msg.append("\n\n");
+
+    if (changeMessage != null) {
+      msg.append(changeMessage);
+      msg.append("\n\n");
+    }
+
+
     addFooter(msg, FOOTER_PATCH_SET, ps);
     if (status != null) {
       addFooter(msg, FOOTER_STATUS, status.name().toLowerCase());
@@ -352,7 +364,8 @@ public class ChangeUpdate extends VersionedMetaData {
     return approvals.isEmpty()
         && reviewers.isEmpty()
         && status == null
-        && submitRecords == null;
+        && submitRecords == null
+        && changeMessage == null;
   }
 
   private static StringBuilder addFooter(StringBuilder sb, FooterKey footer) {

gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeNotesTest.java

@@ -212,6 +212,31 @@ public class ChangeNotesTest {
     }
   }
 
+  @Test
+  public void changeMessageCommitFormatSimple() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.setChangeMessage("Just a little code change.\n"
+        + "How about a new line");
+    update.commit();
+    assertEquals("refs/changes/01/1/meta", update.getRefName());
+
+    RevWalk walk = new RevWalk(repo);
+    try {
+      RevCommit commit = walk.parseCommit(update.getRevision());
+      walk.parseBody(commit);
+      assertEquals("Update patch set 1\n"
+          + "\n"
+          + "Just a little code change.\n"
+          + "How about a new line\n"
+          + "\n"
+          + "Patch-set: 1\n",
+          commit.getFullMessage());
+    } finally {
+      walk.release();
+    }
+  }
+
   @Test
   public void approvalTombstoneCommitFormat() throws Exception {
     Change c = newChange();
@@ -608,6 +633,138 @@ public class ChangeNotesTest {
     assertEquals((short) 2, psas.get(1).getValue());
   }
 
+  @Test
+  public void changeMessageOnePatchSet() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.putReviewer(changeOwner.getAccount().getId(), REVIEWER);
+    update.setChangeMessage("Just a little code change.\n");
+    update.commit();
+
+    ChangeNotes notes = newNotes(c);
+    List<String> changeMessages = notes.getChangeMessages();
+    assertEquals(1, changeMessages.size());
+    assertEquals("Just a little code change.\n", changeMessages.get(0));
+  }
+
+  @Test
+  public void changeMessagesMultiplePatchSets() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.putReviewer(changeOwner.getAccount().getId(), REVIEWER);
+    update.setChangeMessage("This is the change message for the first PS.");
+    update.commit();
+    PatchSet.Id ps1 = c.currentPatchSetId();
+
+    incrementPatchSet(c);
+    update = newUpdate(c, changeOwner);
+
+    update.setChangeMessage("This is the change message for the second PS.");
+    update.commit();
+    PatchSet.Id ps2 = c.currentPatchSetId();
+
+    ChangeNotes notes = newNotes(c);
+    List<String> changeMessages = notes.getChangeMessages();
+    assertEquals(2, changeMessages.size());
+    assertEquals("This is the change message for the second PS.", changeMessages.get(0));
+    assertEquals("This is the change message for the first PS.", changeMessages.get(1));
+  }
+
+  @Test
+  public void noChangeMessage() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.putReviewer(changeOwner.getAccount().getId(), REVIEWER);
+    update.commit();
+
+    RevWalk walk = new RevWalk(repo);
+    try {
+      RevCommit commit = walk.parseCommit(update.getRevision());
+      walk.parseBody(commit);
+      assertEquals("Update patch set 1\n"
+          + "\n"
+          + "Patch-set: 1\n"
+          + "Reviewer: Change Owner <1@gerrit>\n",
+          commit.getFullMessage());
+    } finally {
+      walk.release();
+    }
+
+    ChangeNotes notes = newNotes(c);
+    List<String> changeMessages = notes.getChangeMessages();
+    assertEquals(0, changeMessages.size());
+  }
+
+  @Test
+  public void changeMessageWithTrailingDoubleNewline() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.setChangeMessage("Testing trailing double newline\n"
+        + "\n");
+    update.commit();
+
+    RevWalk walk = new RevWalk(repo);
+    try {
+      RevCommit commit = walk.parseCommit(update.getRevision());
+      walk.parseBody(commit);
+      assertEquals("Update patch set 1\n"
+          + "\n"
+          + "Testing trailing double newline\n"
+          + "\n"
+          + "\n"
+          + "\n"
+          + "Patch-set: 1\n",
+          commit.getFullMessage());
+    } finally {
+      walk.release();
+    }
+
+    ChangeNotes notes = newNotes(c);
+    List<String> changeMessages = notes.getChangeMessages();
+    assertEquals(1, changeMessages.size());
+    assertEquals("Testing trailing double newline\n"
+        + "\n", changeMessages.get(0));
+  }
+
+  @Test
+  public void changeMessageWithMultipleParagraphs() throws Exception {
+    Change c = newChange();
+    ChangeUpdate update = newUpdate(c, changeOwner);
+    update.setChangeMessage("Testing paragraph 1\n"
+        + "\n"
+        + "Testing paragraph 2\n"
+        + "\n"
+        + "Testing paragraph 3");
+    update.commit();
+
+    RevWalk walk = new RevWalk(repo);
+    try {
+      RevCommit commit = walk.parseCommit(update.getRevision());
+      walk.parseBody(commit);
+      assertEquals("Update patch set 1\n"
+          + "\n"
+          + "Testing paragraph 1\n"
+          + "\n"
+          + "Testing paragraph 2\n"
+          + "\n"
+          + "Testing paragraph 3\n"
+          + "\n"
+          + "Patch-set: 1\n",
+          commit.getFullMessage());
+    } finally {
+      walk.release();
+    }
+
+    ChangeNotes notes = newNotes(c);
+    List<String> changeMessages = notes.getChangeMessages();
+    assertEquals(1, changeMessages.size());
+    assertEquals("Testing paragraph 1\n"
+        + "\n"
+        + "Testing paragraph 2\n"
+        + "\n"
+        + "Testing paragraph 3", changeMessages.get(0));
+  }
+
   private Change newChange() {
     Change.Id changeId = new Change.Id(1);
     Change c = new Change(