Tools/Scripts/svn-apply - WebKit - Git at Google

 #!/usr/bin/env perl

 # Copyright (C) 2005, 2006, 2007 Apple Inc.  All rights reserved.
 # Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
 # Copyright (C) 2010 Chris Jerdonek (chris.jerdonek@gmail.com)
 #
 # 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 Apple Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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.

 # "patch" script for WebKit Open Source Project, used to apply patches.

 # Differences from invoking "patch -p0":
 #
 #   Handles added files (does a svn add with logic to handle local changes).
 #   Handles added directories (does a svn add).
 #   Handles removed files (does a svn rm with logic to handle local changes).
 #   Handles removed directories--those with no more files or directories left in them
 #       (does a svn rm).
 #   Has mode where it will roll back to svn version numbers in the patch file so svn
 #       can do a 3-way merge.
 #   Paths from Index: lines are used rather than the paths on the patch lines, which
 #       makes patches generated by "cvs diff" work (increasingly unimportant since we
 #       use Subversion now).
 #   ChangeLog patches use --fuzz=3 to prevent rejects.
 #   Handles binary files (requires patches made by svn-create-patch).
 #   Handles copied and moved files (requires patches made by svn-create-patch).
 #   Handles git-diff patches (without binary changes) created at the top-level directory
 #
 # Missing features:
 #
 #   Handle property changes.
 #   Handle copied and moved directories (would require patches made by svn-create-patch).
 #   When doing a removal, check that old file matches what's being removed.
 #   Notice a patch that's being applied at the "wrong level" and make it work anyway.
 #   Do a dry run on the whole patch and don't do anything if part of the patch is
 #       going to fail (probably too strict unless we exclude ChangeLog).
 #   Handle git-diff patches with binary delta

 use strict;
 use warnings;

 use Digest::MD5;
 use File::Basename;
 use File::Copy qw(copy);
 use File::Spec;
 use Getopt::Long;
 use MIME::Base64;
 use POSIX qw(strftime);

 use FindBin;
 use lib $FindBin::Bin;
 use VCSUtils;

 sub addDirectoriesIfNeeded($);
 sub applyPatch($$;$);
 sub checksum($);
 sub handleBinaryChange($$);
 sub handleGitBinaryChange($$);
 sub isDirectoryEmptyForRemoval($);
 sub patch($);
 sub removeDirectoriesIfNeeded();

 # These should be replaced by an scm class/module:
 sub scmKnowsOfFile($);
 sub scmCopy($$);
 sub scmAdd($);
 sub scmRemove($);

 my $merge = 0;
 my $showHelp = 0;
 my $reviewer;
 my $force = 0;
 my $skipChangeLogs = 0;

 my $optionParseSuccess = GetOptions(
     "merge!" => \$merge,
     "help!" => \$showHelp,
     "reviewer=s" => \$reviewer,
     "force!" => \$force,
     "skip-changelogs" => \$skipChangeLogs
 );

 if (!$optionParseSuccess || $showHelp) {
     print STDERR basename($0) . " [-h|--help] [--force] [-m|--merge] [-r|--reviewer name] [--skip-changelogs] patch1 [patch2 ...]\n";
     exit 1;
 }

 my %removeDirectoryIgnoreList = (
     '.' => 1,
     '..' => 1,
     '.git' => 1,
     '.svn' => 1,
     '_svn' => 1,
 );

 my $epochTime = time(); # This is used to set the date in ChangeLog files.
 my $globalExitStatus = 0;

 my $repositoryRootPath = determineVCSRoot();

 my %checkedDirectories;

 # Need to use a typeglob to pass the file handle as a parameter,
 # otherwise get a bareword error.
 my @diffHashRefs = parsePatch(*ARGV);

 print "Parsed " . @diffHashRefs . " diffs from patch file(s).\n";
 die "No diff found." unless @diffHashRefs;

 my $preparedPatchHash = prepareParsedPatch($force, @diffHashRefs);

 my @copyDiffHashRefs = @{$preparedPatchHash->{copyDiffHashRefs}};
 my @nonCopyDiffHashRefs = @{$preparedPatchHash->{nonCopyDiffHashRefs}};
 my %sourceRevisions = %{$preparedPatchHash->{sourceRevisionHash}};

 if ($merge) {
     die "--merge is currently only supported for SVN" unless isSVN();
     # How do we handle Git patches applied to an SVN checkout here?
     for my $file (sort keys %sourceRevisions) {
         my $version = $sourceRevisions{$file};
         print "Getting version $version of $file\n";
         my $escapedFile = escapeSubversionPath($file);
         system("svn", "update", "-r", $version, $escapedFile) == 0 or die "Failed to run svn update -r $version $escapedFile.";
     }
 }

 # Handle copied and moved files first since moved files may have their
 # source deleted before the move.
 for my $copyDiffHashRef (@copyDiffHashRefs) {
     my $indexPath = $copyDiffHashRef->{indexPath};
     my $copiedFromPath = $copyDiffHashRef->{copiedFromPath};

     addDirectoriesIfNeeded(dirname($indexPath));
     scmCopy($copiedFromPath, $indexPath);
 }

 for my $diffHashRef (@nonCopyDiffHashRefs) {
     patch($diffHashRef);
 }

 removeDirectoriesIfNeeded();

 exit $globalExitStatus;

 sub addDirectoriesIfNeeded($)
 {
     # Git removes a directory once the last file in it is removed. We need
     # explicitly check for the existence of each directory along the path
     # (and create it if it doesn't) so as to support patches that move all files in
     # directory A to A/B. That is, we cannot depend on %checkedDirectories.
     my ($path) = @_;
     my @dirs = File::Spec->splitdir($path);
     my $dir = ".";
     while (scalar @dirs) {
         $dir = File::Spec->catdir($dir, shift @dirs);
         next if !isGit() && exists $checkedDirectories{$dir};
         if (! -e $dir) {
             mkdir $dir or die "Failed to create required directory '$dir' for path '$path'\n";
             scmAdd($dir);
             $checkedDirectories{$dir} = 1;
         }
         elsif (-d $dir) {
             # SVN prints "svn: warning: 'directory' is already under version control"
             # if you try and add a directory which is already in the repository.
             # Git will ignore the add, but re-adding large directories can be sloooow.
             # So we check first to see if the directory is under version control first.
             if (!scmKnowsOfFile($dir)) {
                 scmAdd($dir);
             }
             $checkedDirectories{$dir} = 1;
         }
         else {
             die "'$dir' exists, but is not a directory";
         }
     }
 }

 # Args:
 #   $patch: a patch string.
 #   $pathRelativeToRoot: the path of the file to be patched, relative to the
 #                        repository root. This should normally be the path
 #                        found in the patch's "Index:" line.
 #   $options: a reference to an array of options to pass to the patch command.
 sub applyPatch($$;$)
 {
     my ($patch, $pathRelativeToRoot, $options) = @_;

     my $optionalArgs = {options => $options, ensureForce => $force};

     my $exitStatus = runPatchCommand($patch, $repositoryRootPath, $pathRelativeToRoot, $optionalArgs);

     if ($exitStatus) {
         $globalExitStatus = $exitStatus;
     }
 }

 sub checksum($)
 {
     my $file = shift;
     open(FILE, $file) or die "Can't open '$file': $!";
     binmode(FILE);
     my $checksum = Digest::MD5->new->addfile(*FILE)->hexdigest();
     close(FILE);
     return $checksum;
 }

 sub handleBinaryChange($$)
 {
     my ($fullPath, $contents) = @_;
     # [A-Za-z0-9+/] is the class of allowed base64 characters.
     # One or more lines, at most 76 characters in length.
     # The last line is allowed to have up to two '=' characters at the end (to signify padding).
     if ($contents =~ m#((\n[A-Za-z0-9+/]{76})*\n[A-Za-z0-9+/]{2,74}?[A-Za-z0-9+/=]{2}\n)#) {
         # Addition or Modification
         open FILE, ">", $fullPath or die "Failed to open $fullPath.";
         print FILE decode_base64($1);
         close FILE;
         if (!scmKnowsOfFile($fullPath)) {
             # Addition
             scmAdd($fullPath);
         }
     } else {
         # Deletion
         scmRemove($fullPath);
     }
 }

 sub handleGitBinaryChange($$)
 {
     my ($fullPath, $diffHashRef) = @_;

     my $contents = $diffHashRef->{svnConvertedText};

     my ($binaryChunkType, $binaryChunk, $reverseBinaryChunkType, $reverseBinaryChunk) = decodeGitBinaryPatch($contents, $fullPath);
     if (!$binaryChunkType) {
         die "$fullPath: unknown git binary patch format";
     }

     my $isFileAddition = $diffHashRef->{isNew};
     my $isFileDeletion = $diffHashRef->{isDeletion};

     my $originalContents = "";
     if (open FILE, $fullPath) {
         die "$fullPath already exists" if $isFileAddition;

         $originalContents = join("", <FILE>);
         close FILE;
     }

     if ($reverseBinaryChunkType eq "literal") {
         die "Original content of $fullPath mismatches" if $originalContents ne $reverseBinaryChunk;
     }

     if ($isFileDeletion) {
         scmRemove($fullPath);
     } else {
         # Addition or Modification
         my $out = "";
         if ($binaryChunkType eq "delta") {
             $out = applyGitBinaryPatchDelta($binaryChunk, $originalContents);
         } else {
             $out = $binaryChunk;
         }
         if ($reverseBinaryChunkType eq "delta") {
             die "Original content of $fullPath mismatches" if $originalContents ne applyGitBinaryPatchDelta($reverseBinaryChunk, $out);
         }
         open FILE, ">", $fullPath or die "Failed to open $fullPath.";
         print FILE $out;
         close FILE;
         if ($isFileAddition) {
             scmAdd($fullPath);
         }
     }
 }

 sub isDirectoryEmptyForRemoval($)
 {
     my ($dir) = @_;
     return 1 unless -d $dir;
     my $directoryIsEmpty = 1;
     opendir DIR, $dir or die "Could not open '$dir' to list files: $?";
     for (my $item = readdir DIR; $item && $directoryIsEmpty; $item = readdir DIR) {
         next if exists $removeDirectoryIgnoreList{$item};
         if (-d File::Spec->catdir($dir, $item)) {
             $directoryIsEmpty = 0;
         } else {
             next if (scmWillDeleteFile(File::Spec->catdir($dir, $item)));
             $directoryIsEmpty = 0;
         }
     }
     closedir DIR;
     return $directoryIsEmpty;
 }

 # Args:
 #   $diffHashRef: a diff hash reference of the type returned by parsePatch().
 sub patch($)
 {
     my ($diffHashRef) = @_;

     # Make sure $patch is initialized to some value.  A deletion can have no
     # svnConvertedText property in the case of a deletion resulting from a
     # Git rename.
     my $patch = $diffHashRef->{svnConvertedText} || "";

     my $fullPath = $diffHashRef->{indexPath};
     my $isBinary = $diffHashRef->{isBinary};
     my $isGit = $diffHashRef->{isGit};
     my $hasTextChunks = $patch && $diffHashRef->{numTextChunks};

     my $deletion = 0;
     my $addition = 0;

     $addition = 1 if ($diffHashRef->{isNew} || $patch =~ /\n@@ -0,0 .* @@/);
     $deletion = 1 if ($diffHashRef->{isDeletion} || $patch =~ /\n@@ .* \+0,0 @@/);

     if (basename($fullPath) eq "ChangeLog" && $skipChangeLogs) {
         print "Skipping '$fullPath' since --skip-changelogs was passed on the command line.";
         return;
     }

     if (!$addition && !$deletion && !$isBinary && $hasTextChunks) {
         # Standard patch, patch tool can handle this.
         if (basename($fullPath) eq "ChangeLog") {
             my $changeLogDotOrigExisted = -f "${fullPath}.orig";
             my $changeLogHash = fixChangeLogPatch($patch);
             my $newPatch = setChangeLogDateAndReviewer($changeLogHash->{patch}, $reviewer, $epochTime);
             applyPatch($newPatch, $fullPath, ["--fuzz=3"]);
             unlink("${fullPath}.orig") if (! $changeLogDotOrigExisted);
         } else {
             applyPatch($patch, $fullPath);
         }
     } else {
         # Either a deletion, an addition or a binary change.

         addDirectoriesIfNeeded(dirname($fullPath));

         if ($isBinary) {
             if ($isGit) {
                 handleGitBinaryChange($fullPath, $diffHashRef);
             } else {
                 handleBinaryChange($fullPath, $patch) if $patch;
             }
         } elsif ($deletion) {
             applyPatch($patch, $fullPath, ["--force"]) if $patch;
             scmRemove($fullPath);
         } elsif ($addition && $hasTextChunks) {
             # Addition
             rename($fullPath, "$fullPath.orig") if -e $fullPath;
             applyPatch($patch, $fullPath);
             unlink("$fullPath.orig") if -e "$fullPath.orig" && checksum($fullPath) eq checksum("$fullPath.orig");
             scmAdd($fullPath);
             my $escapedFullPath = escapeSubversionPath("$fullPath.orig");
             # What is this for?
             system("svn", "stat", "$escapedFullPath") if isSVN() && -e "$fullPath.orig";
         }
     }

     scmToggleExecutableBit($fullPath, $diffHashRef->{executableBitDelta}) if defined($diffHashRef->{executableBitDelta});
 }

 sub removeDirectoriesIfNeeded()
 {
     foreach my $dir (reverse sort keys %checkedDirectories) {
         if (isDirectoryEmptyForRemoval($dir)) {
             scmRemove($dir);
         }
     }
 }

 # This could be made into a more general "status" call, except svn and git
 # have different ideas about "moving" files which might get confusing.
 sub scmWillDeleteFile($)
 {
     my ($path) = @_;
     if (isSVN()) {
         my $svnOutput = svnStatus($path);
         return 1 if $svnOutput && substr($svnOutput, 0, 1) eq "D";
     } elsif (isGit()) {
         my $command = runCommand("git", "diff-index", "--name-status", "HEAD", "--", $path);
         return 1 if $command->{stdout} && substr($command->{stdout}, 0, 1) eq "D";
     }
     return 0;
 }

 # Return whether the file at the given path is known to Git.
 #
 # This method outputs a message like the following to STDERR when
 # returning false:
 #
 # "error: pathspec 'test.png' did not match any file(s) known to git.
 #  Did you forget to 'git add'?"
 sub gitKnowsOfFile($)
 {
     my $path = shift;

     `git ls-files --error-unmatch -- $path`;
     my $exitStatus = exitStatus($?);
     return $exitStatus == 0;
 }

 sub scmKnowsOfFile($)
 {
     my ($path) = @_;
     if (isSVN()) {
         my $svnOutput = svnStatus($path);
         # This will match more than intended.  ? might not be the first field in the status
         if ($svnOutput && $svnOutput =~ m#\?\s+$path\n#) {
             return 0;
         }
         # This does not handle errors well.
         return 1;
     } elsif (isGit()) {
         my @result = callSilently(\&gitKnowsOfFile, $path);
         return $result[0];
     }
 }

 sub scmCopy($$)
 {
     my ($source, $destination) = @_;
     if (isSVN()) {
         my $escapedSource = escapeSubversionPath($source);
         my $escapedDestination = escapeSubversionPath($destination);
         system("svn", "copy", $escapedSource, $escapedDestination) == 0 or die "Failed to svn copy $escapedSource $escapedDestination.";
     } elsif (isGit()) {
         copy($source, $destination) or die "Failed to copy $source $destination.";
         system("git", "add", $destination) == 0 or die "Failed to git add $destination.";
     }
 }

 sub scmAdd($)
 {
     my ($path) = @_;
     if (isSVN()) {
         my $escapedPath = escapeSubversionPath($path);
         system("svn", "add", $escapedPath) == 0 or die "Failed to svn add $escapedPath.";
     } elsif (isGit()) {
         system("git", "add", $path) == 0 or die "Failed to git add $path.";
     }
 }

 sub scmRemove($)
 {
     my ($path) = @_;
     if (isSVN()) {
         # SVN is very verbose when removing directories.  Squelch all output except the last line.
         my $svnOutput;
         my $escapedPath = escapeSubversionPath($path);
         open SVN, "svn rm --force '$escapedPath' |" or die "svn rm --force '$escapedPath' failed!";
         # Only print the last line.  Subversion outputs all changed statuses below $dir
         while (<SVN>) {
             $svnOutput = $_;
         }
         close SVN;
         print $svnOutput if $svnOutput;
     } elsif (isGit()) {
         # Git removes a directory if it becomes empty when the last file it contains is
         # removed by `git rm`. In svn-apply this can happen when a directory is being
         # removed in a patch, and all of the files inside of the directory are removed
         # before attemping to remove the directory itself. In this case, Git will have
         # already deleted the directory and `git rm` would exit with an error claiming
         # there was no file. The --ignore-unmatch switch gracefully handles this case.
         system("git", "rm", "--force", "--ignore-unmatch", $path) == 0 or die "Failed to git rm --force --ignore-unmatch $path.";
     }
 }
	#!/usr/bin/env perl

	# Copyright (C) 2005, 2006, 2007 Apple Inc. All rights reserved.
	# Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
	# Copyright (C) 2010 Chris Jerdonek (chris.jerdonek@gmail.com)
	#
	# 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 Apple Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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.

	# "patch" script for WebKit Open Source Project, used to apply patches.

	# Differences from invoking "patch -p0":
	#
	# Handles added files (does a svn add with logic to handle local changes).
	# Handles added directories (does a svn add).
	# Handles removed files (does a svn rm with logic to handle local changes).
	# Handles removed directories--those with no more files or directories left in them
	# (does a svn rm).
	# Has mode where it will roll back to svn version numbers in the patch file so svn
	# can do a 3-way merge.
	# Paths from Index: lines are used rather than the paths on the patch lines, which
	# makes patches generated by "cvs diff" work (increasingly unimportant since we
	# use Subversion now).
	# ChangeLog patches use --fuzz=3 to prevent rejects.
	# Handles binary files (requires patches made by svn-create-patch).
	# Handles copied and moved files (requires patches made by svn-create-patch).
	# Handles git-diff patches (without binary changes) created at the top-level directory
	#
	# Missing features:
	#
	# Handle property changes.
	# Handle copied and moved directories (would require patches made by svn-create-patch).
	# When doing a removal, check that old file matches what's being removed.
	# Notice a patch that's being applied at the "wrong level" and make it work anyway.
	# Do a dry run on the whole patch and don't do anything if part of the patch is
	# going to fail (probably too strict unless we exclude ChangeLog).
	# Handle git-diff patches with binary delta

	use strict;
	use warnings;

	use Digest::MD5;
	use File::Basename;
	use File::Copy qw(copy);
	use File::Spec;
	use Getopt::Long;
	use MIME::Base64;
	use POSIX qw(strftime);

	use FindBin;
	use lib $FindBin::Bin;
	use VCSUtils;

	sub addDirectoriesIfNeeded($);
	sub applyPatch($$;$);
	sub checksum($);
	sub handleBinaryChange($$);
	sub handleGitBinaryChange($$);
	sub isDirectoryEmptyForRemoval($);
	sub patch($);
	sub removeDirectoriesIfNeeded();

	# These should be replaced by an scm class/module:
	sub scmKnowsOfFile($);
	sub scmCopy($$);
	sub scmAdd($);
	sub scmRemove($);

	my $merge = 0;
	my $showHelp = 0;
	my $reviewer;
	my $force = 0;
	my $skipChangeLogs = 0;

	my $optionParseSuccess = GetOptions(
	"merge!" => \$merge,
	"help!" => \$showHelp,
	"reviewer=s" => \$reviewer,
	"force!" => \$force,
	"skip-changelogs" => \$skipChangeLogs
	);

	if (!$optionParseSuccess \|\| $showHelp) {
	print STDERR basename($0) . " [-h\|--help] [--force] [-m\|--merge] [-r\|--reviewer name] [--skip-changelogs] patch1 [patch2 ...]\n";
	exit 1;
	}

	my %removeDirectoryIgnoreList = (
	'.' => 1,
	'..' => 1,
	'.git' => 1,
	'.svn' => 1,
	'_svn' => 1,
	);

	my $epochTime = time(); # This is used to set the date in ChangeLog files.
	my $globalExitStatus = 0;

	my $repositoryRootPath = determineVCSRoot();

	my %checkedDirectories;

	# Need to use a typeglob to pass the file handle as a parameter,
	# otherwise get a bareword error.
	my @diffHashRefs = parsePatch(*ARGV);

	print "Parsed " . @diffHashRefs . " diffs from patch file(s).\n";
	die "No diff found." unless @diffHashRefs;

	my $preparedPatchHash = prepareParsedPatch($force, @diffHashRefs);

	my @copyDiffHashRefs = @{$preparedPatchHash->{copyDiffHashRefs}};
	my @nonCopyDiffHashRefs = @{$preparedPatchHash->{nonCopyDiffHashRefs}};
	my %sourceRevisions = %{$preparedPatchHash->{sourceRevisionHash}};

	if ($merge) {
	die "--merge is currently only supported for SVN" unless isSVN();
	# How do we handle Git patches applied to an SVN checkout here?
	for my $file (sort keys %sourceRevisions) {
	my $version = $sourceRevisions{$file};
	print "Getting version $version of $file\n";
	my $escapedFile = escapeSubversionPath($file);
	system("svn", "update", "-r", $version, $escapedFile) == 0 or die "Failed to run svn update -r $version $escapedFile.";
	}
	}

	# Handle copied and moved files first since moved files may have their
	# source deleted before the move.
	for my $copyDiffHashRef (@copyDiffHashRefs) {
	my $indexPath = $copyDiffHashRef->{indexPath};
	my $copiedFromPath = $copyDiffHashRef->{copiedFromPath};

	addDirectoriesIfNeeded(dirname($indexPath));
	scmCopy($copiedFromPath, $indexPath);
	}

	for my $diffHashRef (@nonCopyDiffHashRefs) {
	patch($diffHashRef);
	}

	removeDirectoriesIfNeeded();

	exit $globalExitStatus;

	sub addDirectoriesIfNeeded($)
	{
	# Git removes a directory once the last file in it is removed. We need
	# explicitly check for the existence of each directory along the path
	# (and create it if it doesn't) so as to support patches that move all files in
	# directory A to A/B. That is, we cannot depend on %checkedDirectories.
	my ($path) = @_;
	my @dirs = File::Spec->splitdir($path);
	my $dir = ".";
	while (scalar @dirs) {
	$dir = File::Spec->catdir($dir, shift @dirs);
	next if !isGit() && exists $checkedDirectories{$dir};
	if (! -e $dir) {
	mkdir $dir or die "Failed to create required directory '$dir' for path '$path'\n";
	scmAdd($dir);
	$checkedDirectories{$dir} = 1;
	}
	elsif (-d $dir) {
	# SVN prints "svn: warning: 'directory' is already under version control"
	# if you try and add a directory which is already in the repository.
	# Git will ignore the add, but re-adding large directories can be sloooow.
	# So we check first to see if the directory is under version control first.
	if (!scmKnowsOfFile($dir)) {
	scmAdd($dir);
	}
	$checkedDirectories{$dir} = 1;
	}
	else {
	die "'$dir' exists, but is not a directory";
	}
	}
	}

	# Args:
	# $patch: a patch string.
	# $pathRelativeToRoot: the path of the file to be patched, relative to the
	# repository root. This should normally be the path
	# found in the patch's "Index:" line.
	# $options: a reference to an array of options to pass to the patch command.
	sub applyPatch($$;$)
	{
	my ($patch, $pathRelativeToRoot, $options) = @_;

	my $optionalArgs = {options => $options, ensureForce => $force};

	my $exitStatus = runPatchCommand($patch, $repositoryRootPath, $pathRelativeToRoot, $optionalArgs);

	if ($exitStatus) {
	$globalExitStatus = $exitStatus;
	}
	}

	sub checksum($)
	{
	my $file = shift;
	open(FILE, $file) or die "Can't open '$file': $!";
	binmode(FILE);
	my $checksum = Digest::MD5->new->addfile(*FILE)->hexdigest();
	close(FILE);
	return $checksum;
	}

	sub handleBinaryChange($$)
	{
	my ($fullPath, $contents) = @_;
	# [A-Za-z0-9+/] is the class of allowed base64 characters.
	# One or more lines, at most 76 characters in length.
	# The last line is allowed to have up to two '=' characters at the end (to signify padding).
	if ($contents =~ m#((\n[A-Za-z0-9+/]{76})*\n[A-Za-z0-9+/]{2,74}?[A-Za-z0-9+/=]{2}\n)#) {
	# Addition or Modification
	open FILE, ">", $fullPath or die "Failed to open $fullPath.";
	print FILE decode_base64($1);
	close FILE;
	if (!scmKnowsOfFile($fullPath)) {
	# Addition
	scmAdd($fullPath);
	}
	} else {
	# Deletion
	scmRemove($fullPath);
	}
	}

	sub handleGitBinaryChange($$)
	{
	my ($fullPath, $diffHashRef) = @_;

	my $contents = $diffHashRef->{svnConvertedText};

	my ($binaryChunkType, $binaryChunk, $reverseBinaryChunkType, $reverseBinaryChunk) = decodeGitBinaryPatch($contents, $fullPath);
	if (!$binaryChunkType) {
	die "$fullPath: unknown git binary patch format";
	}

	my $isFileAddition = $diffHashRef->{isNew};
	my $isFileDeletion = $diffHashRef->{isDeletion};

	my $originalContents = "";
	if (open FILE, $fullPath) {
	die "$fullPath already exists" if $isFileAddition;

	$originalContents = join("", <FILE>);
	close FILE;
	}

	if ($reverseBinaryChunkType eq "literal") {
	die "Original content of $fullPath mismatches" if $originalContents ne $reverseBinaryChunk;
	}

	if ($isFileDeletion) {
	scmRemove($fullPath);
	} else {
	# Addition or Modification
	my $out = "";
	if ($binaryChunkType eq "delta") {
	$out = applyGitBinaryPatchDelta($binaryChunk, $originalContents);
	} else {
	$out = $binaryChunk;
	}
	if ($reverseBinaryChunkType eq "delta") {
	die "Original content of $fullPath mismatches" if $originalContents ne applyGitBinaryPatchDelta($reverseBinaryChunk, $out);
	}
	open FILE, ">", $fullPath or die "Failed to open $fullPath.";
	print FILE $out;
	close FILE;
	if ($isFileAddition) {
	scmAdd($fullPath);
	}
	}
	}

	sub isDirectoryEmptyForRemoval($)
	{
	my ($dir) = @_;
	return 1 unless -d $dir;
	my $directoryIsEmpty = 1;
	opendir DIR, $dir or die "Could not open '$dir' to list files: $?";
	for (my $item = readdir DIR; $item && $directoryIsEmpty; $item = readdir DIR) {
	next if exists $removeDirectoryIgnoreList{$item};
	if (-d File::Spec->catdir($dir, $item)) {
	$directoryIsEmpty = 0;
	} else {
	next if (scmWillDeleteFile(File::Spec->catdir($dir, $item)));
	$directoryIsEmpty = 0;
	}
	}
	closedir DIR;
	return $directoryIsEmpty;
	}

	# Args:
	# $diffHashRef: a diff hash reference of the type returned by parsePatch().
	sub patch($)
	{
	my ($diffHashRef) = @_;

	# Make sure $patch is initialized to some value. A deletion can have no
	# svnConvertedText property in the case of a deletion resulting from a
	# Git rename.
	my $patch = $diffHashRef->{svnConvertedText} \|\| "";

	my $fullPath = $diffHashRef->{indexPath};
	my $isBinary = $diffHashRef->{isBinary};
	my $isGit = $diffHashRef->{isGit};
	my $hasTextChunks = $patch && $diffHashRef->{numTextChunks};

	my $deletion = 0;
	my $addition = 0;

	$addition = 1 if ($diffHashRef->{isNew} \|\| $patch =~ /\n@@ -0,0 .* @@/);
	$deletion = 1 if ($diffHashRef->{isDeletion} \|\| $patch =~ /\n@@ .* \+0,0 @@/);

	if (basename($fullPath) eq "ChangeLog" && $skipChangeLogs) {
	print "Skipping '$fullPath' since --skip-changelogs was passed on the command line.";
	return;
	}

	if (!$addition && !$deletion && !$isBinary && $hasTextChunks) {
	# Standard patch, patch tool can handle this.
	if (basename($fullPath) eq "ChangeLog") {
	my $changeLogDotOrigExisted = -f "${fullPath}.orig";
	my $changeLogHash = fixChangeLogPatch($patch);
	my $newPatch = setChangeLogDateAndReviewer($changeLogHash->{patch}, $reviewer, $epochTime);
	applyPatch($newPatch, $fullPath, ["--fuzz=3"]);
	unlink("${fullPath}.orig") if (! $changeLogDotOrigExisted);
	} else {
	applyPatch($patch, $fullPath);
	}
	} else {
	# Either a deletion, an addition or a binary change.

	addDirectoriesIfNeeded(dirname($fullPath));

	if ($isBinary) {
	if ($isGit) {
	handleGitBinaryChange($fullPath, $diffHashRef);
	} else {
	handleBinaryChange($fullPath, $patch) if $patch;
	}
	} elsif ($deletion) {
	applyPatch($patch, $fullPath, ["--force"]) if $patch;
	scmRemove($fullPath);
	} elsif ($addition && $hasTextChunks) {
	# Addition
	rename($fullPath, "$fullPath.orig") if -e $fullPath;
	applyPatch($patch, $fullPath);
	unlink("$fullPath.orig") if -e "$fullPath.orig" && checksum($fullPath) eq checksum("$fullPath.orig");
	scmAdd($fullPath);
	my $escapedFullPath = escapeSubversionPath("$fullPath.orig");
	# What is this for?
	system("svn", "stat", "$escapedFullPath") if isSVN() && -e "$fullPath.orig";
	}
	}

	scmToggleExecutableBit($fullPath, $diffHashRef->{executableBitDelta}) if defined($diffHashRef->{executableBitDelta});
	}

	sub removeDirectoriesIfNeeded()
	{
	foreach my $dir (reverse sort keys %checkedDirectories) {
	if (isDirectoryEmptyForRemoval($dir)) {
	scmRemove($dir);
	}
	}
	}

	# This could be made into a more general "status" call, except svn and git
	# have different ideas about "moving" files which might get confusing.
	sub scmWillDeleteFile($)
	{
	my ($path) = @_;
	if (isSVN()) {
	my $svnOutput = svnStatus($path);
	return 1 if $svnOutput && substr($svnOutput, 0, 1) eq "D";
	} elsif (isGit()) {
	my $command = runCommand("git", "diff-index", "--name-status", "HEAD", "--", $path);
	return 1 if $command->{stdout} && substr($command->{stdout}, 0, 1) eq "D";
	}
	return 0;
	}

	# Return whether the file at the given path is known to Git.
	#
	# This method outputs a message like the following to STDERR when
	# returning false:
	#
	# "error: pathspec 'test.png' did not match any file(s) known to git.
	# Did you forget to 'git add'?"
	sub gitKnowsOfFile($)
	{
	my $path = shift;

	`git ls-files --error-unmatch -- $path`;
	my $exitStatus = exitStatus($?);
	return $exitStatus == 0;
	}

	sub scmKnowsOfFile($)
	{
	my ($path) = @_;
	if (isSVN()) {
	my $svnOutput = svnStatus($path);
	# This will match more than intended. ? might not be the first field in the status
	if ($svnOutput && $svnOutput =~ m#\?\s+$path\n#) {
	return 0;
	}
	# This does not handle errors well.
	return 1;
	} elsif (isGit()) {
	my @result = callSilently(\&gitKnowsOfFile, $path);
	return $result[0];
	}
	}

	sub scmCopy($$)
	{
	my ($source, $destination) = @_;
	if (isSVN()) {
	my $escapedSource = escapeSubversionPath($source);
	my $escapedDestination = escapeSubversionPath($destination);
	system("svn", "copy", $escapedSource, $escapedDestination) == 0 or die "Failed to svn copy $escapedSource $escapedDestination.";
	} elsif (isGit()) {
	copy($source, $destination) or die "Failed to copy $source $destination.";
	system("git", "add", $destination) == 0 or die "Failed to git add $destination.";
	}
	}

	sub scmAdd($)
	{
	my ($path) = @_;
	if (isSVN()) {
	my $escapedPath = escapeSubversionPath($path);
	system("svn", "add", $escapedPath) == 0 or die "Failed to svn add $escapedPath.";
	} elsif (isGit()) {
	system("git", "add", $path) == 0 or die "Failed to git add $path.";
	}
	}

	sub scmRemove($)
	{
	my ($path) = @_;
	if (isSVN()) {
	# SVN is very verbose when removing directories. Squelch all output except the last line.
	my $svnOutput;
	my $escapedPath = escapeSubversionPath($path);
	open SVN, "svn rm --force '$escapedPath' \|" or die "svn rm --force '$escapedPath' failed!";
	# Only print the last line. Subversion outputs all changed statuses below $dir
	while (<SVN>) {
	$svnOutput = $_;
	}
	close SVN;
	print $svnOutput if $svnOutput;
	} elsif (isGit()) {
	# Git removes a directory if it becomes empty when the last file it contains is
	# removed by `git rm`. In svn-apply this can happen when a directory is being
	# removed in a patch, and all of the files inside of the directory are removed
	# before attemping to remove the directory itself. In this case, Git will have
	# already deleted the directory and `git rm` would exit with an error claiming
	# there was no file. The --ignore-unmatch switch gracefully handles this case.
	system("git", "rm", "--force", "--ignore-unmatch", $path) == 0 or die "Failed to git rm --force --ignore-unmatch $path.";
	}
	}