[EGIT PATCH 08/31] Add dryRun option to Transport and console push

[Marek Zawirski <marek.zawirski@gmail.com>]

Implementation of C Git --dry-run behavior for push operation.
It allows investigating possible push result, while not performing real
push operation - not updating remote refs.

Signed-off-by: Marek Zawirski <marek.zawirski@gmail.com>
---
 .../src/org/spearce/jgit/pgm/Push.java             |    4 ++
 .../org/spearce/jgit/transport/PushProcess.java    |   18 +++++++-
 .../src/org/spearce/jgit/transport/Transport.java  |   40 ++++++++++++++++++--
 3 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Push.java b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Push.java
index a952309..f5b24c6 100644
--- a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Push.java
+++ b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Push.java
@@ -85,6 +85,9 @@ class Push extends TextBuiltin {
 
 	@Option(name = "--receive-pack", metaVar = "path")
 	private String receivePack;
+	
+	@Option(name = "--dry-run")
+	private boolean dryRun = Transport.DEFAULT_DRY_RUN;
 
 	private boolean shownURI;
 
@@ -102,6 +105,7 @@ class Push extends TextBuiltin {
 			transport.setPushThin(thin);
 			if (receivePack != null)
 				transport.setOptionReceivePack(receivePack);
+			transport.setDryRun(dryRun);
 
 			final Collection<RemoteRefUpdate> toPush = transport
 					.findRemoteRefUpdatesFor(refSpecs);
diff --git a/org.spearce.jgit/src/org/spearce/jgit/transport/PushProcess.java b/org.spearce.jgit/src/org/spearce/jgit/transport/PushProcess.java
index 6a2176f..cafec05 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/transport/PushProcess.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/transport/PushProcess.java
@@ -100,7 +100,10 @@ class PushProcess {
 	/**
 	 * Perform push operation between local and remote repository - set remote
 	 * refs appropriately, send needed objects and update local tracking refs.
-	 *
+	 * <p>
+	 * When {@link Transport#isDryRun()} is true, result of this operation is
+	 * just estimation of real operation result, no real action is performed.
+	 * 
 	 * @param monitor
 	 *            progress monitor used for feedback about operation.
 	 * @return result of push operation with complete status description.
@@ -118,12 +121,15 @@ class PushProcess {
 			monitor.endTask();
 
 			final Map<String, RemoteRefUpdate> preprocessed = prepareRemoteUpdates();
-			if (!preprocessed.isEmpty())
+			if (transport.isDryRun())
+				modifyUpdatesForDryRun();
+			else if (!preprocessed.isEmpty())
 				connection.push(monitor, preprocessed);
 		} finally {
 			connection.close();
 		}
-		updateTrackingRefs();
+		if (!transport.isDryRun())
+			updateTrackingRefs();
 		return prepareOperationResult();
 	}
 
@@ -191,6 +197,12 @@ class PushProcess {
 		return result;
 	}
 
+	private void modifyUpdatesForDryRun() {
+		for (final RemoteRefUpdate rru : toPush.values())
+			if (rru.getStatus() == Status.NOT_ATTEMPTED)
+				rru.setStatus(Status.OK);
+	}
+
 	private void updateTrackingRefs() {
 		for (final RemoteRefUpdate rru : toPush.values()) {
 			final Status status = rru.getStatus();
diff --git a/org.spearce.jgit/src/org/spearce/jgit/transport/Transport.java b/org.spearce.jgit/src/org/spearce/jgit/transport/Transport.java
index 73aa771..98853e6 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/transport/Transport.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/transport/Transport.java
@@ -236,6 +236,11 @@ public abstract class Transport {
 	public static final RefSpec REFSPEC_PUSH_ALL = new RefSpec(
 			"refs/heads/*:refs/heads/*");
 
+	/**
+	 * Default setting for {@link #dryRun} option.
+	 */
+	public static final boolean DEFAULT_DRY_RUN = false;
+
 	/** The repository this transport fetches into, or pushes out of. */
 	protected final Repository local;
 
@@ -271,6 +276,9 @@ public abstract class Transport {
 	/** Should push produce thin-pack when sending objects to remote repository. */
 	private boolean pushThin = DEFAULT_PUSH_THIN;
 
+	/** Should push just check for operation result, not really push. */
+	private boolean dryRun = DEFAULT_DRY_RUN;
+
 	/**
 	 * Create a new transport instance.
 	 * 
@@ -426,6 +434,27 @@ public abstract class Transport {
 	}
 
 	/**
+	 * @return true if push operation should just check for possible result and
+	 *         not really update remote refs, false otherwise - when push should
+	 *         act normally.
+	 */
+	public boolean isDryRun() {
+		return dryRun;
+	}
+
+	/**
+	 * Set dry run option for push operation.
+	 * 
+	 * @param dryRun
+	 *            true if push operation should just check for possible result
+	 *            and not really update remote refs, false otherwise - when push
+	 *            should act normally.
+	 */
+	public void setDryRun(final boolean dryRun) {
+		this.dryRun = dryRun;
+	}
+
+	/**
 	 * Fetch objects and refs from the remote repository to the local one.
 	 * <p>
 	 * This is a utility function providing standard fetch behavior. Local
@@ -495,10 +524,13 @@ public abstract class Transport {
 	 * operation result is provided after execution.
 	 * <p>
 	 * For setting up remote ref update specification from ref spec, see helper
-	 * method {@link #findRemoteRefUpdatesFor(Collection)}, predefined refspecs ({@link #REFSPEC_TAGS},
-	 * {@link #REFSPEC_PUSH_ALL}) or consider using directly
-	 * {@link RemoteRefUpdate} for more possibilities.
-	 *
+	 * method {@link #findRemoteRefUpdatesFor(Collection)}, predefined refspecs
+	 * ({@link #REFSPEC_TAGS}, {@link #REFSPEC_PUSH_ALL}) or consider using
+	 * directly {@link RemoteRefUpdate} for more possibilities.
+	 * <p>
+	 * When {@link #isDryRun()} is true, result of this operation is just
+	 * estimation of real operation result, no real action is performed.
+	 * 
 	 * @see RemoteRefUpdate
 	 *
 	 * @param monitor
-- 
1.5.6.3