Support branch specific labels

By default a given project's label applicable scope is all changes
on all branches of this project and its child projects.

Label's applicable scope can be branch specific via configuration.
E.g. create a label 'Video-Qualify' on parent project and configure
the 'branch' as:

[label "Video-Qualify"]
    branch = refs/heads/video-1.0/*
    branch = refs/heads/video-1.1/Kino

Then ONLY changes in above branch scope of parent project and child
projects will be affected by 'Video-Qualify'.

Please note the 'branch' is independent from the branch scope related
to access control defined in 'access' parts in 'project.config' file.
That means from the UI a user can always assign permissions for that
label on a branch, but this permission is then ignored if the label
doesn't apply for that branch.

Change-Id: I414e62503b0da4af022abbc9988593ba9ac87916

Documentation/config-labels.txt

@@ -244,6 +244,30 @@ If false, the label cannot be overridden by child projects. Any
 configuration for this label in child projects will be ignored. Defaults
 to true.
 
+[[label_branch]]
+`label.Label-Name.branch`
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+By default a given project's label applicable scope is all changes
+on all branches of this project and its child projects.
+
+Label's applicable scope can be branch specific via configuration.
+E.g. create a label `Video-Qualify` on parent project and configure
+the `branch` as:
+
+====
+  [label "Video-Qualify"]
+      branch = refs/heads/video-1.0/*
+      branch = refs/heads/video-1.1/Kino
+====
+
+Then *only* changes in above branch scope of parent project and child
+projects will be affected by `Video-Qualify`.
+
+NOTE: The `branch` is independent from the branch scope defined in `access`
+parts in `project.config` file. That means from the UI a user can always
+assign permissions for that label on a branch, but this permission is then
+ignored if the label doesn't apply for that branch.
 
 [[label_example]]
 Example

gerrit-common/src/main/java/com/google/gerrit/common/data/LabelType.java

@@ -103,6 +103,7 @@ public class LabelType {
   protected short maxPositive;
 
   private transient boolean canOverride;
+  private transient List<String> refPatterns;
   private transient List<Integer> intList;
   private transient Map<Short, LabelValue> byValue;
 
@@ -157,10 +158,18 @@ public class LabelType {
     return canOverride;
   }
 
+  public List<String> getRefPatterns() {
+    return refPatterns;
+  }
+
   public void setCanOverride(boolean canOverride) {
     this.canOverride = canOverride;
   }
 
+  public void setRefPatterns(List<String> refPatterns) {
+    this.refPatterns = refPatterns;
+  }
+
   public List<LabelValue> getValues() {
     return values;
   }

gerrit-server/src/main/java/com/google/gerrit/server/git/ProjectConfig.java

@@ -59,6 +59,7 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.StringReader;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumSet;
@@ -127,6 +128,7 @@ public class ProjectConfig extends VersionedMetaData {
   private static final String KEY_COPY_MAX_SCORE = "copyMaxScore";
   private static final String KEY_VALUE = "value";
   private static final String KEY_CAN_OVERRIDE = "canOverride";
+  private static final String KEY_Branch = "branch";
   private static final Set<String> LABEL_FUNCTIONS = ImmutableSet.of(
       "MaxWithBlock", "AnyWithBlock", "MaxNoBlock", "NoBlock", "NoOp");
 
@@ -651,10 +653,17 @@ public class ProjectConfig extends VersionedMetaData {
           rc.getBoolean(LABEL, name, KEY_COPY_MAX_SCORE, false));
       label.setCanOverride(
           rc.getBoolean(LABEL, name, KEY_CAN_OVERRIDE, true));
+      label.setRefPatterns(getStringListOrNull(rc, LABEL, name, KEY_Branch));
       labelSections.put(name, label);
     }
   }
 
+  private List<String> getStringListOrNull(Config rc, String section,
+      String subSection, String name) {
+    String[] ac = rc.getStringList(section, subSection, name);
+    return ac.length == 0 ? null : Arrays.asList(ac);
+  }
+
   private void loadCommentLinkSections(Config rc) {
     Set<String> subsections = rc.getSubsections(COMMENTLINK);
     commentLinkSections = Lists.newArrayListWithCapacity(subsections.size());

gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java

@@ -14,8 +14,11 @@
 
 package com.google.gerrit.server.project;
 
+import com.google.common.collect.Lists;
+import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.LabelTypes;
 import com.google.gerrit.common.data.PermissionRange;
+import com.google.gerrit.common.data.RefConfigSection;
 import com.google.gerrit.common.data.SubmitRecord;
 import com.google.gerrit.common.data.SubmitTypeRecord;
 import com.google.gerrit.reviewdb.client.Account;
@@ -242,9 +245,28 @@ public class ChangeControl {
         && getRefControl().canUpload(); // as long as you can upload too
   }
 
-  /** All available label types for this project. */
+  /** All available label types for this change. */
   public LabelTypes getLabelTypes() {
-    return getProjectControl().getLabelTypes();
+    String destBranch = getChange().getDest().get();
+    List<LabelType> all = getProjectControl().getLabelTypes().getLabelTypes();
+
+    List<LabelType> r = Lists.newArrayListWithCapacity(all.size());
+    for (LabelType l : all) {
+      List<String> refs = l.getRefPatterns();
+      if (refs == null) {
+        r.add(l);
+      } else {
+        for (String refPattern : refs) {
+          if (RefConfigSection.isValid(refPattern)
+              && match(destBranch, refPattern)) {
+            r.add(l);
+            break;
+          }
+        }
+      }
+    }
+
+    return new LabelTypes(r);
   }
 
   /** All value ranges of any allowed label permission. */
@@ -403,6 +425,11 @@ public class ChangeControl {
     return resultsToSubmitRecord(evaluator.getSubmitRule(), results);
   }
 
+  private boolean match(String destBranch, String refPattern) {
+    return RefPatternMatcher.getMatcher(refPattern).match(destBranch,
+        this.getRefControl().getCurrentUser().getUserName());
+  }
+
   private List<SubmitRecord> cannotSubmitDraft(ReviewDb db, PatchSet patchSet,
       ChangeData cd) {
     try {

gerrit-server/src/main/java/gerrit/PRED_get_legacy_label_types_1.java

@@ -16,9 +16,7 @@ package gerrit;
 
 import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.LabelValue;
-import com.google.gerrit.rules.PrologEnvironment;
 import com.google.gerrit.rules.StoredValues;
-import com.google.gerrit.server.project.ProjectState;
 
 import com.googlecode.prolog_cafe.lang.IntegerTerm;
 import com.googlecode.prolog_cafe.lang.ListTerm;
@@ -55,14 +53,8 @@ class PRED_get_legacy_label_types_1 extends Predicate.P1 {
   public Operation exec(Prolog engine) throws PrologException {
     engine.setB0();
     Term a1 = arg1.dereference();
-
+    List<LabelType> list =
-    PrologEnvironment env = (PrologEnvironment) engine.control;
+        StoredValues.CHANGE_CONTROL.get(engine).getLabelTypes().getLabelTypes();
-    ProjectState state = env.getArgs().getProjectCache()
-        .get(StoredValues.CHANGE.get(engine).getDest().getParentKey());
-    if (state == null) {
-      return engine.fail();
-    }
-    List<LabelType> list = state.getLabelTypes().getLabelTypes();
     Term head = Prolog.Nil;
     for (int idx = list.size() - 1; 0 <= idx; idx--) {
       head = new ListTerm(export(list.get(idx)), head);