Accept in_reply_to to thread inline comments

The in_reply_to field supplies the id of another comment, enabling
threading. Because id is URL encoded to match a REST API we also
encode the in_reply_to field, allowing clients to correctly line up
messages by simple string equality.

Change-Id: Idc6af51873b9b8a12707c6f4df9d25b627e8b409

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/PatchLineComment.java

@@ -185,4 +185,8 @@ public final class PatchLineComment {
   public String getParentUuid() {
     return parentUuid;
   }
+
+  public void setParentUuid(String inReplyTo) {
+    parentUuid = inReplyTo;
+  }
 }

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

@@ -25,6 +25,7 @@ import com.google.gerrit.reviewdb.client.PatchLineComment.Status;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.change.PutDraft.Input;
+import com.google.gerrit.server.util.Url;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
@@ -60,7 +61,7 @@ class CreateDraft implements RestModifyView<RevisionResource, Input> {
             ChangeUtil.messageUUID(db.get())),
         in.line != null ? in.line : 0,
         rsrc.getAuthorId(),
-        null);
+        Url.decode(in.inReplyTo));
     c.setStatus(Status.DRAFT);
     c.setSide(in.side == GetDraft.Side.PARENT ? (short) 0 : (short) 1);
     c.setMessage(in.message.trim());

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

@@ -41,6 +41,7 @@ class GetDraft implements RestReadView<DraftResource> {
     String path;
     Side side;
     Integer line;
+    String inReplyTo;
     String message;
     Timestamp updated;
 
@@ -53,6 +54,7 @@ class GetDraft implements RestReadView<DraftResource> {
       if (c.getLine() > 0) {
         line = c.getLine();
       }
+      inReplyTo = Url.encode(c.getParentUuid());
       message = Strings.emptyToNull(c.getMessage());
       updated = c.getWrittenOn();
     }

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

@@ -39,6 +39,7 @@ import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.change.PostReview.Input;
 import com.google.gerrit.server.project.ChangeControl;
+import com.google.gerrit.server.util.Url;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 
@@ -85,6 +86,7 @@ public class PostReview implements RestModifyView<RevisionResource, Input> {
     String id;
     GetDraft.Side side;
     int line;
+    String inReplyTo;
     String message;
   }
 
@@ -261,6 +263,7 @@ public class PostReview implements RestModifyView<RevisionResource, Input> {
     for (Map.Entry<String, List<Comment>> ent : in.entrySet()) {
       String path = ent.getKey();
       for (Comment c : ent.getValue()) {
+        String parent = Url.decode(c.inReplyTo);
         PatchLineComment e = drafts.remove(c.id);
         boolean create = e == null;
         if (create) {
@@ -270,7 +273,9 @@ public class PostReview implements RestModifyView<RevisionResource, Input> {
                   ChangeUtil.messageUUID(db)),
               c.line,
               rsrc.getAuthorId(),
-              null);
+              parent);
+        } else if (parent != null) {
+          e.setParentUuid(parent);
         }
         e.setStatus(PatchLineComment.Status.PUBLISHED);
         e.setWrittenOn(timestamp);

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

@@ -24,6 +24,8 @@ import com.google.gerrit.reviewdb.client.PatchLineComment;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.change.GetDraft.Side;
 import com.google.gerrit.server.change.PutDraft.Input;
+import com.google.gerrit.server.util.Url;
+import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
@@ -37,6 +39,7 @@ class PutDraft implements RestModifyView<DraftResource, Input> {
     String path;
     Side side;
     Integer line;
+    String inReplyTo;
     Timestamp updated; // Accepted but ignored.
 
     @DefaultInput
@@ -58,9 +61,9 @@ class PutDraft implements RestModifyView<DraftResource, Input> {
   }
 
   @Override
-  public Object apply(DraftResource rsrc, Input in)
+  public Object apply(DraftResource rsrc, Input in) throws AuthException,
-      throws AuthException, BadRequestException, ResourceConflictException,
+      BadRequestException, ResourceConflictException, OrmException {
-      Exception {
+    PatchLineComment c = rsrc.getComment();
     if (in == null || in.message == null || in.message.trim().isEmpty()) {
       return delete.get().apply(rsrc, null);
     } else if (in.kind != null && !"gerritcodereview#comment".equals(in.kind)) {
@@ -69,20 +72,19 @@ class PutDraft implements RestModifyView<DraftResource, Input> {
       throw new BadRequestException("line must be >= 0");
     }
 
-    PatchLineComment c = rsrc.getComment();
     if (in.path != null
         && !in.path.equals(c.getKey().getParentKey().getFileName())) {
       // Updating the path alters the primary key, which isn't possible.
       // Delete then recreate the comment instead of an update.
       db.get().patchComments().delete(Collections.singleton(c));
-      c = update(new PatchLineComment(
+      c = new PatchLineComment(
           new PatchLineComment.Key(
               new Patch.Key(rsrc.getPatchSet().getId(), in.path),
               c.getKey().get()),
           c.getLine(),
           rsrc.getAuthorId(),
-          c.getParentUuid()), in);
+          c.getParentUuid());
-      db.get().patchComments().insert(Collections.singleton(c));
+      db.get().patchComments().insert(Collections.singleton(update(c, in)));
     } else {
       db.get().patchComments().update(Collections.singleton(update(c, in)));
     }
@@ -96,6 +98,9 @@ class PutDraft implements RestModifyView<DraftResource, Input> {
     if (in.line != null) {
       e.setLine(in.line);
     }
+    if (in.inReplyTo != null) {
+      e.setParentUuid(Url.decode(in.inReplyTo));
+    }
     e.setMessage(in.message.trim());
     e.updated();
     return e;

gerrit-server/src/main/java/com/google/gerrit/server/util/Url.java

@@ -38,21 +38,27 @@ public final class Url {
    * @return a string with all invalid URL characters escaped.
    */
   public static String encode(String component) {
+    if (component != null) {
       try {
         return URLEncoder.encode(component, "UTF-8");
       } catch (UnsupportedEncodingException e) {
         throw new RuntimeException("JVM must support UTF-8", e);
       }
     }
+    return null;
+  }
 
   /** Decode a URL encoded string, e.g. from {@code "%2F"} to {@code "/"}. */
   public static String decode(String str) {
+    if (str != null) {
       try {
         return URLDecoder.decode(str, "UTF-8");
       } catch (UnsupportedEncodingException e) {
         throw new RuntimeException("JVM must support UTF-8", e);
       }
     }
+    return null;
+  }
 
   private Url() {
   }