Expand submodule subscription support

Current sub module implementation limits the support to sites where
the canonical site name matches the server in the .gitmodules
file. Some sites run the web front end of Gerrit on a different
address than the SSH server, but they still want to utilize the
submodule subscription support.

This patch checks the [sshd] section of the gerrit.config
configuration file to extract the "proper" ssh server name. If the
server name is different from the canoncial web address Gerrit will
use the configured SSH host name when checking the .gitmodules file in
the super repository.

Change-Id: I48dc3964e130c624cc395dbe80f87f36aa8c19f8

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

@@ -21,6 +21,7 @@ import com.google.gerrit.reviewdb.client.SubmoduleSubscription;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.config.CanonicalWebUrl;
+import com.google.gerrit.server.config.SshdListenAddress;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
 import com.google.gerrit.server.util.SubmoduleSectionParser;
 import com.google.gwtorm.server.OrmException;
@@ -78,6 +79,7 @@ public class SubmoduleOp {
   private RevCommit mergeTip;
   private RevWalk rw;
   private final Provider<String> urlProvider;
+  private final Provider<String> sshProvider;
   private ReviewDb schema;
   private Repository db;
   private Project destProject;
@@ -93,6 +95,7 @@ public class SubmoduleOp {
   public SubmoduleOp(@Assisted final Branch.NameKey destBranch,
       @Assisted RevCommit mergeTip, @Assisted RevWalk rw,
       @CanonicalWebUrl @Nullable final Provider<String> urlProvider,
+      @SshdListenAddress @Nullable final Provider<String> sshProvider,
       final SchemaFactory<ReviewDb> sf, @Assisted Repository db,
       @Assisted Project destProject, @Assisted List<Change> submitted,
       @Assisted final Map<Change.Id, CodeReviewCommit> commits,
@@ -102,6 +105,7 @@ public class SubmoduleOp {
     this.mergeTip = mergeTip;
     this.rw = rw;
     this.urlProvider = urlProvider;
+    this.sshProvider = sshProvider;
     this.schemaFactory = sf;
     this.db = db;
     this.destProject = destProject;
@@ -137,6 +141,32 @@ public class SubmoduleOp {
     }
 
     try {
+      String thisServer = null;
+      String sshHostname = null;
+      String webHostname = new URI(urlProvider.get()).getHost();
+
+      // If SSH is disabled on the command line there will be no
+      // sshProvider to ask. Translate this to the gerrit.config
+      // option "off" inside the [sshd] section.
+      if (sshProvider == null) {
+        sshHostname = "off";
+      } else {
+        // Make sure we only remove the port part and not a substring
+        // of an IPv6 address.
+        sshHostname = sshProvider.get().split(":\\d+$")[0];
+      }
+      // Use the web host name (canonical web url) for the following
+      // conditions:
+      // - If the ssh hostname is the same as the web host
+      // - If we listen on all addresses
+      // - If sshd is turned off
+      if (webHostname.equals(sshHostname) || sshHostname.equals("*") ||
+          sshHostname.equals("off")) {
+        thisServer = webHostname;
+      } else {
+        thisServer = sshHostname;
+      }
+
       final TreeWalk tw = TreeWalk.forPath(db, GIT_MODULES, mergeTip.getTree());
       if (tw != null
           && (FileMode.REGULAR_FILE.equals(tw.getRawMode(0)) || FileMode.EXECUTABLE_FILE
@@ -145,8 +175,6 @@ public class SubmoduleOp {
         BlobBasedConfig bbc =
             new BlobBasedConfig(null, db, mergeTip, GIT_MODULES);
 
-        final String thisServer = new URI(urlProvider.get()).getHost();
-
         final Branch.NameKey target =
             new Branch.NameKey(new Project.NameKey(destProject.getName()),
                 destBranch.get());