Implement multiple branches in ls-project

Allow users request SHA1 of multiple branches per command:

$ ssh -p 29418 review.example.com gerrit ls-projects -b eclair -b gingerbread

In case if a branch is not visible or does not exists then stub is shown. Here is
a sample of the command output:

---------------------------------------- d8a9e45c7ec6ff97b44fdbd0b21cabdb69f5f15b foo
---------------------------------------- 87e4297f8f508e9b73863b27c25a551a4d4b5ed5 bar
a7e9587229246f6eb876795bc45a09c17b3bed51 862b2ce84f38e93a50d29510e713475f11228b28 baz
405cd3f5d7df7bae701b313dad9ce2ef797eb754 6a7eb2f0c885d03320b58afb662ee4fc14659063 hello
---------------------------------------- 782effdaeba782a656f799c9584dcc82fbfb7fa7 world
b8240b951de6c03f72278dd3d7790c2355878197 e8099cc12a3b64aa4e58b319e61f0190e27bd3ac kext

Change-Id: Ib05a6fc770ed0b70a3c180b2a41bec5e95a7117b

Documentation/cmd-ls-projects.txt

@@ -8,7 +8,7 @@ gerrit ls-projects - List projects visible to caller
 SYNOPSIS
 --------
 [verse]
-'ssh' -p <port> <host> 'gerrit ls-projects' [\--show-branch <BRANCH>]
+'ssh' -p <port> <host> 'gerrit ls-projects' [\--show-branch <BRANCH1> ...]
 
 DESCRIPTION
 -----------
@@ -30,7 +30,13 @@ OPTIONS
 -------
 \--show-branch::
 \-b::
-	Name of the branch for which the command will display the sha of each project.
+	Branch for which the command will display the sha of each project.
+	The command may have multiple \--show-branch parameters, in this case
+	sha will be shown for each of the branches.
+	If the user does not have READ access to some branch or the branch does not
+	exist then stub (forty '\-' symbols) is shown.
+	If the user does not have access to any branch in the project then the
+	whole project is not shown.
 
 \--tree::
 \-t::

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/ListProjects.java

@@ -49,8 +49,9 @@ final class ListProjects extends BaseCommand {
   @Inject
   private GitRepositoryManager repoManager;
 
-  @Option(name = "--show-branch", aliases = {"-b"}, usage = "displays the sha of each project in the specified branch")
+  @Option(name = "--show-branch", aliases = {"-b"}, multiValued = true,
-  private String showBranch;
+      usage = "displays the sha of each project in the specified branch")
+  private List<String> showBranch;
 
   @Option(name = "--tree", aliases = {"-t"}, usage = "displays project inheritance in a tree-like format\n" +
       "this option does not work together with the show-branch option")
@@ -102,16 +103,37 @@ final class ListProjects extends BaseCommand {
           }
 
           if (showBranch != null) {
-            final Ref ref = getBranchRef(projectName);
+            final List<Ref> refs = getBranchRefs(projectName);
-            if (ref == null || ref.getObjectId() == null
+            if (refs == null) {
-                || !pctl.controlForRef(ref.getLeaf().getName()).isVisible()) {
-              // No branch, or the user can't see this branch, so skip it.
-              //
               continue;
             }
 
-            stdout.print(ref.getObjectId().name());
+            boolean hasVisibleRefs = false;
-            stdout.print(' ');
+            for (int i = 0; i < refs.size(); i++) {
+              Ref ref = refs.get(i);
+              if (ref == null
+                || ref.getObjectId() == null
+                || !pctl.controlForRef(ref.getLeaf().getName()).isVisible()) {
+                // No branch, or the user can't see this branch, so remove it.
+                refs.set(i, null);
+              } else {
+                hasVisibleRefs = true;
+              }
+            }
+
+            if (!hasVisibleRefs) {
+             continue;
+            }
+
+            for (Ref ref : refs) {
+              if (ref == null) {
+                // Print stub (forty '-' symbols)
+                stdout.print("----------------------------------------");
+              } else {
+                stdout.print(ref.getObjectId().name());
+              }
+              stdout.print(' ');
+            }
           }
 
           stdout.print(projectName.get() + "\n");
@@ -151,11 +173,15 @@ final class ListProjects extends BaseCommand {
     }
   }
 
-  private Ref getBranchRef(Project.NameKey projectName) {
+  private List<Ref> getBranchRefs(Project.NameKey projectName) {
     try {
       final Repository r = repoManager.openRepository(projectName);
       try {
-        return r.getRef(showBranch);
+        final List<Ref> result = new ArrayList<Ref>(showBranch.size());
+        for (String branch : showBranch) {
+          result.add(r.getRef(branch));
+        }
+        return result;
       } finally {
         r.close();
       }