Generalize Change.Id methods for parsing from refnames

Handle edit refs from Change.Id#fromRef, and add a new method
#fromAllUsersRef for parsing from refs in All-Users. Note that it's
not possible to combine these into one method that takes a project
name, since at this low level in the code we don't have access to the
live config-based AllUsersName.

Change-Id: I55ae5340efa964bbe7965a0a491ae27ce620044c

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

@@ -143,6 +143,9 @@ public final class Change {
     }
 
     public static Id fromRef(String ref) {
+      if (RefNames.isRefsEdit(ref)) {
+        return fromEditRefPart(ref);
+      }
       int cs = startIndex(ref);
       if (cs < 0) {
         return null;
@@ -156,6 +159,42 @@ public final class Change {
       return null;
     }
 
+    public static Id fromAllUsersRef(String ref) {
+      if (ref == null) {
+        return null;
+      }
+      String prefix;
+      if (ref.startsWith(RefNames.REFS_STARRED_CHANGES)) {
+        prefix = RefNames.REFS_STARRED_CHANGES;
+      } else if (ref.startsWith(RefNames.REFS_DRAFT_COMMENTS)) {
+        prefix = RefNames.REFS_DRAFT_COMMENTS;
+      } else {
+        return null;
+      }
+      int cs = startIndex(ref, prefix);
+      if (cs < 0) {
+        return null;
+      }
+      int ce = nextNonDigit(ref, cs);
+      if (ce < ref.length() && ref.charAt(ce) == '/'
+          && isNumeric(ref, ce + 1)) {
+        return new Change.Id(Integer.parseInt(ref.substring(cs, ce)));
+      }
+      return null;
+    }
+
+    private static boolean isNumeric(String s, int off) {
+      if (off >= s.length()) {
+        return false;
+      }
+      for (int i = off; i < s.length(); i++) {
+        if (!Character.isDigit(s.charAt(i))) {
+          return false;
+        }
+      }
+      return true;
+    }
+
     public static Id fromEditRefPart(String ref) {
       int startChangeId = ref.indexOf(RefNames.EDIT_PREFIX) +
           RefNames.EDIT_PREFIX.length();
@@ -173,12 +212,16 @@ public final class Change {
     }
 
     static int startIndex(String ref) {
-      if (ref == null || !ref.startsWith(REFS_CHANGES)) {
+      return startIndex(ref, REFS_CHANGES);
+    }
+
+    static int startIndex(String ref, String expectedPrefix) {
+      if (ref == null || !ref.startsWith(expectedPrefix)) {
         return -1;
       }
 
       // Last 2 digits.
-      int ls = REFS_CHANGES.length();
+      int ls = expectedPrefix.length();
       int le = nextNonDigit(ref, ls);
       if (le - ls != 2 || le >= ref.length() || ref.charAt(le) != '/') {
         return -1;

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

@@ -195,7 +195,8 @@ public class RefNames {
   }
 
   public static boolean isRefsEdit(String ref) {
-    return ref.startsWith(REFS_USERS) && ref.contains(EDIT_PREFIX);
+    return ref != null && ref.startsWith(REFS_USERS)
+        && ref.contains(EDIT_PREFIX);
   }
 
   public static boolean isRefsUsers(String ref) {

gerrit-reviewdb/src/test/java/com/google/gerrit/reviewdb/client/ChangeTest.java

@@ -63,6 +63,15 @@ public class ChangeTest {
     assertNotRef("refs/changes/34/1234foo");
   }
 
+  @Test
+  public void parseEditRefNames() {
+    assertRef(5, "refs/users/34/1234/edit-5/1");
+    assertRef(5, "refs/users/34/1234/edit-5");
+    assertNotRef("refs/changes/34/1234/edit-5/1");
+    assertNotRef("refs/users/34/1234/EDIT-5/1");
+    assertNotRef("refs/users/34/1234");
+  }
+
   @Test
   public void parseChangeMetaRefNames() {
     assertRef(1, "refs/changes/01/1/meta");
@@ -73,6 +82,44 @@ public class ChangeTest {
     assertNotRef("refs/changes/01/1/1/meta");
   }
 
+  @Test
+  public void parseRobotCommentRefNames() {
+    assertRef(1, "refs/changes/01/1/robot-comments");
+    assertRef(1234, "refs/changes/34/1234/robot-comments");
+
+    assertNotRef("refs/changes/01/1/robot-comment");
+    assertNotRef("refs/changes/01/1/ROBOT-COMMENTS");
+    assertNotRef("refs/changes/01/1/1/robot-comments");
+  }
+
+  @Test
+  public void parseStarredChangesRefNames() {
+    assertAllUsersRef(1, "refs/starred-changes/01/1/1001");
+    assertAllUsersRef(1234, "refs/starred-changes/34/1234/1001");
+
+    assertNotRef("refs/starred-changes/01/1/1001");
+    assertNotAllUsersRef(null);
+    assertNotAllUsersRef("refs/starred-changes/01/1/1xx1");
+    assertNotAllUsersRef("refs/starred-changes/01/1/");
+    assertNotAllUsersRef("refs/starred-changes/01/1");
+    assertNotAllUsersRef("refs/starred-changes/35/1234/1001");
+    assertNotAllUsersRef("refs/starred-changeS/01/1/1001");
+  }
+
+  @Test
+  public void parseDraftRefNames() {
+    assertAllUsersRef(1, "refs/draft-comments/01/1/1001");
+    assertAllUsersRef(1234, "refs/draft-comments/34/1234/1001");
+
+    assertNotRef("refs/draft-comments/01/1/1001");
+    assertNotAllUsersRef(null);
+    assertNotAllUsersRef("refs/draft-comments/01/1/1xx1");
+    assertNotAllUsersRef("refs/draft-comments/01/1/");
+    assertNotAllUsersRef("refs/draft-comments/01/1");
+    assertNotAllUsersRef("refs/draft-comments/35/1234/1001");
+    assertNotAllUsersRef("refs/draft-commentS/01/1/1001");
+  }
+
   @Test
   public void toRefPrefix() {
     assertThat(new Change.Id(1).toRefPrefix())
@@ -110,6 +157,15 @@ public class ChangeTest {
     assertThat(Change.Id.fromRef(refName)).isNull();
   }
 
+  private static void assertAllUsersRef(int changeId, String refName) {
+    assertThat(Change.Id.fromAllUsersRef(refName))
+        .isEqualTo(new Change.Id(changeId));
+  }
+
+  private static void assertNotAllUsersRef(String refName) {
+    assertThat(Change.Id.fromAllUsersRef(refName)).isNull();
+  }
+
   private static void assertRefPart(int changeId, String refName) {
     assertEquals(new Change.Id(changeId), Change.Id.fromRefPart(refName));
   }