retrieve only new git commits, do not collect commits from existing branches

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/GitHookChangesetCollector.java

@@ -49,6 +49,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import sonia.scm.util.IOUtil;
+import sonia.scm.web.CollectingPackParserListener;
 
 //~--- JDK imports ------------------------------------------------------------
 
@@ -56,6 +57,7 @@ import java.io.IOException;
 
 import java.util.List;
 
+
 /**
  *
  * @author Sebastian Sdorra
@@ -83,6 +85,7 @@ public class GitHookChangesetCollector
   {
     this.rpack = rpack;
     this.receiveCommands = receiveCommands;
+    this.listener = CollectingPackParserListener.get(rpack);
   }
 
   //~--- methods --------------------------------------------------------------
@@ -110,6 +113,16 @@ public class GitHookChangesetCollector
 
       for (ReceiveCommand rc : receiveCommands)
       {
+        //J-
+        logger.trace("handle receive command, type={}, ref={}, result={}",
+          new Object[] {
+            rc.getType(),
+            rc.getRefName(),
+            rc.getResult()
+          }
+        );
+        //J+
+
         if (rc.getType() != ReceiveCommand.Type.DELETE)
         {
           try
@@ -163,16 +176,6 @@ public class GitHookChangesetCollector
     GitChangesetConverter converter, RevWalk walk, ReceiveCommand rc)
     throws IncorrectObjectTypeException, IOException
   {
-    //J-
-    logger.trace("handle receive command, type={}, ref={}, result={}",
-      new Object[] {
-        rc.getType(),
-        rc.getRefName(),
-        rc.getResult()
-      }
-    );
-    //J+
-
     ObjectId newId = rc.getNewId();
 
     String branch = GitUtil.getBranch(rc.getRefName());
@@ -201,14 +204,23 @@ public class GitHookChangesetCollector
     while (commit != null)
     {
 
-      // parse commit body to avoid npe
-      walk.parseBody(commit);
+      // only append new commits
+      if (listener.isNew(commit))
+      {
 
-      Changeset changeset = converter.createChangeset(commit, branches);
+        // parse commit body to avoid npe
+        walk.parseBody(commit);
 
-      logger.trace("retrive commit {} for hook", changeset.getId());
+        Changeset changeset = converter.createChangeset(commit, branches);
 
-      changesets.add(changeset);
+        logger.trace("retrieve commit {} for hook", changeset.getId());
+
+        changesets.add(changeset);
+      }
+      else
+      {
+        logger.trace("commit {} was already received", commit.getId());
+      }
 
       commit = walk.next();
     }
@@ -216,6 +228,9 @@ public class GitHookChangesetCollector
 
   //~--- fields ---------------------------------------------------------------
 
+  /** listener to track new objects */
+  private final CollectingPackParserListener listener;
+
   /** Field description */
   private final List<ReceiveCommand> receiveCommands;
 

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/web/CollectingPackParserListener.java

@@ -0,0 +1,195 @@
+/**
+ * Copyright (c) 2014, Sebastian Sdorra All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. Redistributions in
+ * binary form must reproduce the above copyright notice, this list of
+ * conditions and the following disclaimer in the documentation and/or other
+ * materials provided with the distribution. 3. Neither the name of SCM-Manager;
+ * nor the names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.web;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableSet;
+
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectIdSubclassMap;
+import org.eclipse.jgit.revwalk.RevObject;
+import org.eclipse.jgit.transport.BaseReceivePack;
+import org.eclipse.jgit.transport.BaseReceivePack.PackParserListener;
+import org.eclipse.jgit.transport.PackParser;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.util.Set;
+
+/**
+ * Implementation of {@link PackParserListener} to collect every object which is
+ * pushed with the reveive pack. The listener is used to find out which object
+ * is new and which was already pushed.
+ *
+ * @author Sebastian Sdorra
+ */
+public class CollectingPackParserListener implements PackParserListener
+{
+
+  /**
+   * the logger for CollectingPackParserListener
+   */
+  private static final Logger logger =
+    LoggerFactory.getLogger(CollectingPackParserListener.class);
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Returns the listener from the receive pack.
+   *
+   *
+   * @param pack receive pack
+   *
+   * @return listener
+   */
+  public static CollectingPackParserListener get(BaseReceivePack pack)
+  {
+    PackParserListener listener = pack.getPackParserListener();
+
+    if (listener == null)
+    {
+      throw new IllegalArgumentException(
+        "receive pack does not contain a listener");
+    }
+
+    Preconditions.checkArgument(
+      listener instanceof CollectingPackParserListener,
+      "listener is not a CollectingPackParserListener");
+
+    return (CollectingPackParserListener) listener;
+  }
+
+  //~--- set methods ----------------------------------------------------------
+
+  /**
+   * Applies the listener to the receive pack.
+   *
+   *
+   * @param pack receive pack
+   */
+  public static void set(BaseReceivePack pack)
+  {
+    logger.trace("apply collecting listener to receive pack");
+    pack.setPackParserListener(new CollectingPackParserListener());
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Collects all new object ids.
+   *
+   *
+   * @param parser pack parser
+   */
+  @Override
+  public void after(PackParser parser)
+  {
+    logger.trace("retrieve new object ids from pack parser");
+
+    ObjectIdSubclassMap<ObjectId> newObjectIdMap = parser.getNewObjectIds();
+
+    if (newObjectIdMap != null)
+    {
+      newObjectIds = ImmutableSet.copyOf(newObjectIdMap);
+    }
+    else
+    {
+      logger.warn("pack parser returned no newObjectIds");
+      newObjectIds = ImmutableSet.of();
+    }
+
+    if (newObjectIds.isEmpty())
+    {
+      logger.debug("new object ids are empty, we treat every commit as new");
+    }
+    else
+    {
+      logger.debug("collected {} new object ids", newObjectIds.size());
+    }
+  }
+
+  /**
+   * Prepares the pack parser to retrieve the new object ids.
+   *
+   *
+   * @param parser pack parser
+   */
+  @Override
+  public void before(PackParser parser)
+  {
+    logger.trace("prepare pack parser to collect new object ids");
+    parser.setNeedNewObjectIds(true);
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Returns {@code true} if the object is a new object. The method will also
+   * return {@code true}, if the pack parser does not return a list with new
+   * object ids.
+   *
+   *
+   * @param object rev object
+   *
+   * @return {@code true} if the object is new
+   */
+  public boolean isNew(RevObject object)
+  {
+    ensureAfterWasCalled();
+
+    return newObjectIds.isEmpty() || newObjectIds.contains(object.getId());
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Throws an {@link IllegalStateException} if the after method was not called.
+   */
+  private void ensureAfterWasCalled()
+  {
+    if (newObjectIds == null)
+    {
+      throw new IllegalStateException( "Pack parser seem not to be finished. "
+        + "The receive pack has not called the after method of the listener.");
+    }
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** set of new object ids */
+  private Set<ObjectId> newObjectIds;
+}

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/web/GitReceivePackFactory.java

@@ -96,7 +96,9 @@ public class GitReceivePackFactory
 
     rpack.setPreReceiveHook(hook);
     rpack.setPostReceiveHook(hook);
-
+    // apply collecting listener, to be able to check which commits are new
+    CollectingPackParserListener.set(rpack);
+    
     return rpack;
   }