java/com/google/gerrit/git/RefUpdateUtil.java - gerrit - Git at Google

 // Copyright (C) 2017 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 package com.google.gerrit.git;

 import static com.google.common.collect.ImmutableList.toImmutableList;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
 import com.google.common.flogger.FluentLogger;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.io.IOException;
 import java.util.Optional;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.BatchRefUpdate;
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.transport.ReceiveCommand;

 /** Static utilities for working with JGit's ref update APIs. */
 public class RefUpdateUtil {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();

   /**
    * Execute a batch ref update, throwing a checked exception if not all updates succeeded.
    *
    * <p>Creates a new {@link RevWalk} used only for this operation.
    *
    * @param bru batch update; should already have been executed.
    * @param repo repository that created {@code bru}.
    * @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
    *     #checkResults(BatchRefUpdate)} for details.
    * @throws IOException if any result was not {@code OK}.
    */
   public static void executeChecked(BatchRefUpdate bru, Repository repo) throws IOException {
     try (RevWalk rw = new RevWalk(repo)) {
       executeChecked(bru, rw);
     }
   }

   /**
    * Execute a batch ref update, throwing a checked exception if not all updates succeeded.
    *
    * @param bru batch update; should already have been executed.
    * @param rw walk for executing the update.
    * @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
    *     #checkResults(BatchRefUpdate)} for details.
    * @throws IOException if any result was not {@code OK}.
    */
   public static void executeChecked(BatchRefUpdate bru, RevWalk rw) throws IOException {
     logger.atFine().log(
         "Executing ref updates: %s\n",
         Joiner.on("\n")
             .join(
                 bru.getCommands().stream()
                     .map(
                         cmd ->
                             String.format(
                                 "%s (new tree ID: %s)",
                                 cmd, getNewTreeId(rw, cmd).map(ObjectId::name).orElse("n/a")))
                     .collect(toImmutableList())));
     bru.execute(rw, NullProgressMonitor.INSTANCE);
     checkResults(bru);
   }

   private static Optional<ObjectId> getNewTreeId(RevWalk revWalk, ReceiveCommand cmd) {
     if (ReceiveCommand.Type.DELETE.equals(cmd.getType())) {
       // Ref deletions do not have a new tree.
       return Optional.empty();
     }

     try {
       return Optional.of(revWalk.parseCommit(cmd.getNewId()).getTree());
     } catch (IOException e) {
       logger.atWarning().withCause(e).log(
           "Failed parsing new commit %s for ref update: %s", cmd.getNewId().name(), cmd);
       return Optional.empty();
     }
   }

   /**
    * Check results of all commands in the update batch, reducing to a single exception if there was
    * a failure.
    *
    * <p>Throws {@link LockFailureException} if at least one command failed with {@code
    * LOCK_FAILURE}, and the entire transaction was aborted, i.e. any non-{@code LOCK_FAILURE}
    * results, if there were any, failed with "transaction aborted".
    *
    * <p>In particular, if the underlying ref database does not {@link
    * org.eclipse.jgit.lib.RefDatabase#performsAtomicTransactions() perform atomic transactions},
    * then a combination of {@code LOCK_FAILURE} on one ref and {@code OK} or another result on other
    * refs will <em>not</em> throw {@code LockFailureException}.
    *
    * @param bru batch update; should already have been executed.
    * @throws LockFailureException if the transaction was aborted due to lock failure.
    * @throws IOException if any result was not {@code OK}.
    */
   @VisibleForTesting
   static void checkResults(BatchRefUpdate bru) throws IOException {
     if (bru.getCommands().isEmpty()) {
       return;
     }

     int lockFailure = 0;
     int aborted = 0;
     int failure = 0;

     for (ReceiveCommand cmd : bru.getCommands()) {
       if (cmd.getResult() != ReceiveCommand.Result.OK) {
         failure++;
       }
       if (cmd.getResult() == ReceiveCommand.Result.LOCK_FAILURE) {
         lockFailure++;
       } else if (cmd.getResult() == ReceiveCommand.Result.REJECTED_OTHER_REASON
           && JGitText.get().transactionAborted.equals(cmd.getMessage())) {
         aborted++;
       }
     }

     if (lockFailure + aborted == bru.getCommands().size()) {
       throw new LockFailureException("Update aborted with one or more lock failures: " + bru, bru);
     } else if (failure > 0) {
       throw new GitUpdateFailureException("Update failed: " + bru, bru);
     }
   }

   /**
    * Check results of a single ref update, throwing an exception if there was a failure.
    *
    * @param ru ref update; must already have been executed.
    * @throws IllegalArgumentException if the result was {@code NOT_ATTEMPTED}.
    * @throws LockFailureException if the result was {@code LOCK_FAILURE}.
    * @throws IOException if the result failed for another reason.
    */
   public static void checkResult(RefUpdate ru) throws IOException {
     RefUpdate.Result result = ru.getResult();
     switch (result) {
       case NOT_ATTEMPTED:
         throw new IllegalArgumentException("Not attempted: " + ru.getName());
       case NEW:
       case FORCED:
       case NO_CHANGE:
       case FAST_FORWARD:
       case RENAMED:
         return;
       case LOCK_FAILURE:
         throw new LockFailureException("Failed to update " + ru.getName() + ": " + result, ru);
       default:
       case IO_FAILURE:
       case REJECTED:
       case REJECTED_CURRENT_BRANCH:
       case REJECTED_MISSING_OBJECT:
       case REJECTED_OTHER_REASON:
         throw new GitUpdateFailureException(
             "Failed to update " + ru.getName() + ": " + ru.getResult(), ru);
     }
   }

   /**
    * Delete a single ref, throwing a checked exception on failure.
    *
    * <p>Does not require that the ref have any particular old value. Succeeds as a no-op if the ref
    * did not exist.
    *
    * @param repo repository.
    * @param refName ref name to delete.
    * @throws LockFailureException if a low-level lock failure (e.g. compare-and-swap failure)
    *     occurs.
    * @throws IOException if an error occurred.
    */
   @CanIgnoreReturnValue
   public static RefUpdate deleteChecked(Repository repo, String refName) throws IOException {
     RefUpdate ru = repo.updateRef(refName);
     ru.setForceUpdate(true);
     ru.setCheckConflicting(false);
     switch (ru.delete()) {
       case FORCED:
         // Ref was deleted.
         return ru;

       case NEW:
         // Ref didn't exist (yes, really).
         return ru;

       case LOCK_FAILURE:
         throw new LockFailureException("Failed to delete " + refName + ": " + ru.getResult(), ru);

         // Not really failures, but should not be the result of a deletion, so the best option is to
         // throw.
       case NO_CHANGE:
       case FAST_FORWARD:
       case RENAMED:
       case NOT_ATTEMPTED:

       case IO_FAILURE:
       case REJECTED:
       case REJECTED_CURRENT_BRANCH:
       case REJECTED_MISSING_OBJECT:
       case REJECTED_OTHER_REASON:
       default:
         throw new GitUpdateFailureException(
             "Failed to delete " + refName + ": " + ru.getResult(), ru);
     }
   }

   private RefUpdateUtil() {}
 }
	// Copyright (C) 2017 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	package com.google.gerrit.git;

	import static com.google.common.collect.ImmutableList.toImmutableList;

	import com.google.common.annotations.VisibleForTesting;
	import com.google.common.base.Joiner;
	import com.google.common.flogger.FluentLogger;
	import com.google.errorprone.annotations.CanIgnoreReturnValue;
	import java.io.IOException;
	import java.util.Optional;
	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.lib.BatchRefUpdate;
	import org.eclipse.jgit.lib.NullProgressMonitor;
	import org.eclipse.jgit.lib.ObjectId;
	import org.eclipse.jgit.lib.RefUpdate;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.revwalk.RevWalk;
	import org.eclipse.jgit.transport.ReceiveCommand;

	/** Static utilities for working with JGit's ref update APIs. */
	public class RefUpdateUtil {
	private static final FluentLogger logger = FluentLogger.forEnclosingClass();

	/**
	* Execute a batch ref update, throwing a checked exception if not all updates succeeded.
	*
	* <p>Creates a new {@link RevWalk} used only for this operation.
	*
	* @param bru batch update; should already have been executed.
	* @param repo repository that created {@code bru}.
	* @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
	* #checkResults(BatchRefUpdate)} for details.
	* @throws IOException if any result was not {@code OK}.
	*/
	public static void executeChecked(BatchRefUpdate bru, Repository repo) throws IOException {
	try (RevWalk rw = new RevWalk(repo)) {
	executeChecked(bru, rw);
	}
	}

	/**
	* Execute a batch ref update, throwing a checked exception if not all updates succeeded.
	*
	* @param bru batch update; should already have been executed.
	* @param rw walk for executing the update.
	* @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
	* #checkResults(BatchRefUpdate)} for details.
	* @throws IOException if any result was not {@code OK}.
	*/
	public static void executeChecked(BatchRefUpdate bru, RevWalk rw) throws IOException {
	logger.atFine().log(
	"Executing ref updates: %s\n",
	Joiner.on("\n")
	.join(
	bru.getCommands().stream()
	.map(
	cmd ->
	String.format(
	"%s (new tree ID: %s)",
	cmd, getNewTreeId(rw, cmd).map(ObjectId::name).orElse("n/a")))
	.collect(toImmutableList())));
	bru.execute(rw, NullProgressMonitor.INSTANCE);
	checkResults(bru);
	}

	private static Optional<ObjectId> getNewTreeId(RevWalk revWalk, ReceiveCommand cmd) {
	if (ReceiveCommand.Type.DELETE.equals(cmd.getType())) {
	// Ref deletions do not have a new tree.
	return Optional.empty();
	}

	try {
	return Optional.of(revWalk.parseCommit(cmd.getNewId()).getTree());
	} catch (IOException e) {
	logger.atWarning().withCause(e).log(
	"Failed parsing new commit %s for ref update: %s", cmd.getNewId().name(), cmd);
	return Optional.empty();
	}
	}

	/**
	* Check results of all commands in the update batch, reducing to a single exception if there was
	* a failure.
	*
	* <p>Throws {@link LockFailureException} if at least one command failed with {@code
	* LOCK_FAILURE}, and the entire transaction was aborted, i.e. any non-{@code LOCK_FAILURE}
	* results, if there were any, failed with "transaction aborted".
	*
	* <p>In particular, if the underlying ref database does not {@link
	* org.eclipse.jgit.lib.RefDatabase#performsAtomicTransactions() perform atomic transactions},
	* then a combination of {@code LOCK_FAILURE} on one ref and {@code OK} or another result on other
	* refs will <em>not</em> throw {@code LockFailureException}.
	*
	* @param bru batch update; should already have been executed.
	* @throws LockFailureException if the transaction was aborted due to lock failure.
	* @throws IOException if any result was not {@code OK}.
	*/
	@VisibleForTesting
	static void checkResults(BatchRefUpdate bru) throws IOException {
	if (bru.getCommands().isEmpty()) {
	return;
	}

	int lockFailure = 0;
	int aborted = 0;
	int failure = 0;

	for (ReceiveCommand cmd : bru.getCommands()) {
	if (cmd.getResult() != ReceiveCommand.Result.OK) {
	failure++;
	}
	if (cmd.getResult() == ReceiveCommand.Result.LOCK_FAILURE) {
	lockFailure++;
	} else if (cmd.getResult() == ReceiveCommand.Result.REJECTED_OTHER_REASON
	&& JGitText.get().transactionAborted.equals(cmd.getMessage())) {
	aborted++;
	}
	}

	if (lockFailure + aborted == bru.getCommands().size()) {
	throw new LockFailureException("Update aborted with one or more lock failures: " + bru, bru);
	} else if (failure > 0) {
	throw new GitUpdateFailureException("Update failed: " + bru, bru);
	}
	}

	/**
	* Check results of a single ref update, throwing an exception if there was a failure.
	*
	* @param ru ref update; must already have been executed.
	* @throws IllegalArgumentException if the result was {@code NOT_ATTEMPTED}.
	* @throws LockFailureException if the result was {@code LOCK_FAILURE}.
	* @throws IOException if the result failed for another reason.
	*/
	public static void checkResult(RefUpdate ru) throws IOException {
	RefUpdate.Result result = ru.getResult();
	switch (result) {
	case NOT_ATTEMPTED:
	throw new IllegalArgumentException("Not attempted: " + ru.getName());
	case NEW:
	case FORCED:
	case NO_CHANGE:
	case FAST_FORWARD:
	case RENAMED:
	return;
	case LOCK_FAILURE:
	throw new LockFailureException("Failed to update " + ru.getName() + ": " + result, ru);
	default:
	case IO_FAILURE:
	case REJECTED:
	case REJECTED_CURRENT_BRANCH:
	case REJECTED_MISSING_OBJECT:
	case REJECTED_OTHER_REASON:
	throw new GitUpdateFailureException(
	"Failed to update " + ru.getName() + ": " + ru.getResult(), ru);
	}
	}

	/**
	* Delete a single ref, throwing a checked exception on failure.
	*
	* <p>Does not require that the ref have any particular old value. Succeeds as a no-op if the ref
	* did not exist.
	*
	* @param repo repository.
	* @param refName ref name to delete.
	* @throws LockFailureException if a low-level lock failure (e.g. compare-and-swap failure)
	* occurs.
	* @throws IOException if an error occurred.
	*/
	@CanIgnoreReturnValue
	public static RefUpdate deleteChecked(Repository repo, String refName) throws IOException {
	RefUpdate ru = repo.updateRef(refName);
	ru.setForceUpdate(true);
	ru.setCheckConflicting(false);
	switch (ru.delete()) {
	case FORCED:
	// Ref was deleted.
	return ru;

	case NEW:
	// Ref didn't exist (yes, really).
	return ru;

	case LOCK_FAILURE:
	throw new LockFailureException("Failed to delete " + refName + ": " + ru.getResult(), ru);

	// Not really failures, but should not be the result of a deletion, so the best option is to
	// throw.
	case NO_CHANGE:
	case FAST_FORWARD:
	case RENAMED:
	case NOT_ATTEMPTED:

	case IO_FAILURE:
	case REJECTED:
	case REJECTED_CURRENT_BRANCH:
	case REJECTED_MISSING_OBJECT:
	case REJECTED_OTHER_REASON:
	default:
	throw new GitUpdateFailureException(
	"Failed to delete " + refName + ": " + ru.getResult(), ru);
	}
	}

	private RefUpdateUtil() {}
	}