refs: document transaction semantics
[gitweb.git] / git-p4.py
index 36c5c55b61b6dc16c27c219099654611a5b085f5..c33dece5d29ebf59fa0b78a9fda2de48114b1fe3 100755 (executable)
--- a/git-p4.py
+++ b/git-p4.py
@@ -22,6 +22,9 @@
 import re
 import shutil
 import stat
+import zipfile
+import zlib
+import ctypes
 
 try:
     from subprocess import CalledProcessError
@@ -104,6 +107,16 @@ def chdir(path, is_client_path=False):
         path = os.getcwd()
     os.environ['PWD'] = path
 
+def calcDiskFree():
+    """Return free space in bytes on the disk of the given dirname."""
+    if platform.system() == 'Windows':
+        free_bytes = ctypes.c_ulonglong(0)
+        ctypes.windll.kernel32.GetDiskFreeSpaceExW(ctypes.c_wchar_p(os.getcwd()), None, None, ctypes.pointer(free_bytes))
+        return free_bytes.value
+    else:
+        st = os.statvfs(os.getcwd())
+        return st.f_bavail * st.f_frsize
+
 def die(msg):
     if verbose:
         raise Exception(msg)
@@ -190,14 +203,16 @@ def p4_has_move_command():
     # assume it failed because @... was invalid changelist
     return True
 
-def system(cmd):
+def system(cmd, ignore_error=False):
     expand = isinstance(cmd,basestring)
     if verbose:
         sys.stderr.write("executing %s\n" % str(cmd))
     retcode = subprocess.call(cmd, shell=expand)
-    if retcode:
+    if retcode and not ignore_error:
         raise CalledProcessError(retcode, cmd)
 
+    return retcode
+
 def p4_system(cmd):
     """Specifically invoke p4 as the system command. """
     real_cmd = p4_build_cmd(cmd)
@@ -540,7 +555,12 @@ def p4Where(depotPath):
     return clientPath
 
 def currentGitBranch():
-    return read_pipe("git name-rev HEAD").split(" ")[1].strip()
+    retcode = system(["git", "symbolic-ref", "-q", "HEAD"], ignore_error=True)
+    if retcode != 0:
+        # on a detached head
+        return None
+    else:
+        return read_pipe(["git", "name-rev", "HEAD"]).split(" ")[1].strip()
 
 def isValidGitDir(path):
     if (os.path.exists(path + "/HEAD")
@@ -602,9 +622,12 @@ def gitBranchExists(branch):
 
 _gitConfig = {}
 
-def gitConfig(key):
+def gitConfig(key, typeSpecifier=None):
     if not _gitConfig.has_key(key):
-        cmd = [ "git", "config", key ]
+        cmd = [ "git", "config" ]
+        if typeSpecifier:
+            cmd += [ typeSpecifier ]
+        cmd += [ key ]
         s = read_pipe(cmd, ignore_error=True)
         _gitConfig[key] = s.strip()
     return _gitConfig[key]
@@ -615,16 +638,26 @@ def gitConfigBool(key):
        in the config."""
 
     if not _gitConfig.has_key(key):
-        cmd = [ "git", "config", "--bool", key ]
+        _gitConfig[key] = gitConfig(key, '--bool') == "true"
+    return _gitConfig[key]
+
+def gitConfigInt(key):
+    if not _gitConfig.has_key(key):
+        cmd = [ "git", "config", "--int", key ]
         s = read_pipe(cmd, ignore_error=True)
         v = s.strip()
-        _gitConfig[key] = v == "true"
+        try:
+            _gitConfig[key] = int(gitConfig(key, '--int'))
+        except ValueError:
+            _gitConfig[key] = None
     return _gitConfig[key]
 
 def gitConfigList(key):
     if not _gitConfig.has_key(key):
         s = read_pipe(["git", "config", "--get-all", key], ignore_error=True)
         _gitConfig[key] = s.strip().split(os.linesep)
+        if _gitConfig[key] == ['']:
+            _gitConfig[key] = []
     return _gitConfig[key]
 
 def p4BranchesInGit(branchesAreInRemotes=True):
@@ -789,39 +822,37 @@ def p4ChangesForPaths(depotPaths, changeRange, requestedBlockSize):
                 die("cannot use --changes-block-size with non-numeric revisions")
             block_size = None
 
-    # Accumulate change numbers in a dictionary to avoid duplicates
-    changes = {}
+    changes = []
 
-    for p in depotPaths:
-        # Retrieve changes a block at a time, to prevent running
-        # into a MaxResults/MaxScanRows error from the server.
+    # Retrieve changes a block at a time, to prevent running
+    # into a MaxResults/MaxScanRows error from the server.
 
-        while True:
-            cmd = ['changes']
+    while True:
+        cmd = ['changes']
 
-            if block_size:
-                end = min(changeEnd, changeStart + block_size)
-                revisionRange = "%d,%d" % (changeStart, end)
-            else:
-                revisionRange = "%s,%s" % (changeStart, changeEnd)
+        if block_size:
+            end = min(changeEnd, changeStart + block_size)
+            revisionRange = "%d,%d" % (changeStart, end)
+        else:
+            revisionRange = "%s,%s" % (changeStart, changeEnd)
 
+        for p in depotPaths:
             cmd += ["%s...@%s" % (p, revisionRange)]
 
-            for line in p4_read_pipe_lines(cmd):
-                changeNum = int(line.split(" ")[1])
-                changes[changeNum] = True
+        # Insert changes in chronological order
+        for line in reversed(p4_read_pipe_lines(cmd)):
+            changes.append(int(line.split(" ")[1]))
 
-            if not block_size:
-                break
+        if not block_size:
+            break
 
-            if end >= changeEnd:
-                break
+        if end >= changeEnd:
+            break
 
-            changeStart = end + 1
+        changeStart = end + 1
 
-    changelist = changes.keys()
-    changelist.sort()
-    return changelist
+    changes = sorted(changes)
+    return changes
 
 def p4PathStartsWith(path, prefix):
     # This method tries to remedy a potential mixed-case issue:
@@ -907,6 +938,182 @@ def wildcard_present(path):
     m = re.search("[*#@%]", path)
     return m is not None
 
+class LargeFileSystem(object):
+    """Base class for large file system support."""
+
+    def __init__(self, writeToGitStream):
+        self.largeFiles = set()
+        self.writeToGitStream = writeToGitStream
+
+    def generatePointer(self, cloneDestination, contentFile):
+        """Return the content of a pointer file that is stored in Git instead of
+           the actual content."""
+        assert False, "Method 'generatePointer' required in " + self.__class__.__name__
+
+    def pushFile(self, localLargeFile):
+        """Push the actual content which is not stored in the Git repository to
+           a server."""
+        assert False, "Method 'pushFile' required in " + self.__class__.__name__
+
+    def hasLargeFileExtension(self, relPath):
+        return reduce(
+            lambda a, b: a or b,
+            [relPath.endswith('.' + e) for e in gitConfigList('git-p4.largeFileExtensions')],
+            False
+        )
+
+    def generateTempFile(self, contents):
+        contentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
+        for d in contents:
+            contentFile.write(d)
+        contentFile.close()
+        return contentFile.name
+
+    def exceedsLargeFileThreshold(self, relPath, contents):
+        if gitConfigInt('git-p4.largeFileThreshold'):
+            contentsSize = sum(len(d) for d in contents)
+            if contentsSize > gitConfigInt('git-p4.largeFileThreshold'):
+                return True
+        if gitConfigInt('git-p4.largeFileCompressedThreshold'):
+            contentsSize = sum(len(d) for d in contents)
+            if contentsSize <= gitConfigInt('git-p4.largeFileCompressedThreshold'):
+                return False
+            contentTempFile = self.generateTempFile(contents)
+            compressedContentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
+            zf = zipfile.ZipFile(compressedContentFile.name, mode='w')
+            zf.write(contentTempFile, compress_type=zipfile.ZIP_DEFLATED)
+            zf.close()
+            compressedContentsSize = zf.infolist()[0].compress_size
+            os.remove(contentTempFile)
+            os.remove(compressedContentFile.name)
+            if compressedContentsSize > gitConfigInt('git-p4.largeFileCompressedThreshold'):
+                return True
+        return False
+
+    def addLargeFile(self, relPath):
+        self.largeFiles.add(relPath)
+
+    def removeLargeFile(self, relPath):
+        self.largeFiles.remove(relPath)
+
+    def isLargeFile(self, relPath):
+        return relPath in self.largeFiles
+
+    def processContent(self, git_mode, relPath, contents):
+        """Processes the content of git fast import. This method decides if a
+           file is stored in the large file system and handles all necessary
+           steps."""
+        if self.exceedsLargeFileThreshold(relPath, contents) or self.hasLargeFileExtension(relPath):
+            contentTempFile = self.generateTempFile(contents)
+            (git_mode, contents, localLargeFile) = self.generatePointer(contentTempFile)
+
+            # Move temp file to final location in large file system
+            largeFileDir = os.path.dirname(localLargeFile)
+            if not os.path.isdir(largeFileDir):
+                os.makedirs(largeFileDir)
+            shutil.move(contentTempFile, localLargeFile)
+            self.addLargeFile(relPath)
+            if gitConfigBool('git-p4.largeFilePush'):
+                self.pushFile(localLargeFile)
+            if verbose:
+                sys.stderr.write("%s moved to large file system (%s)\n" % (relPath, localLargeFile))
+        return (git_mode, contents)
+
+class MockLFS(LargeFileSystem):
+    """Mock large file system for testing."""
+
+    def generatePointer(self, contentFile):
+        """The pointer content is the original content prefixed with "pointer-".
+           The local filename of the large file storage is derived from the file content.
+           """
+        with open(contentFile, 'r') as f:
+            content = next(f)
+            gitMode = '100644'
+            pointerContents = 'pointer-' + content
+            localLargeFile = os.path.join(os.getcwd(), '.git', 'mock-storage', 'local', content[:-1])
+            return (gitMode, pointerContents, localLargeFile)
+
+    def pushFile(self, localLargeFile):
+        """The remote filename of the large file storage is the same as the local
+           one but in a different directory.
+           """
+        remotePath = os.path.join(os.path.dirname(localLargeFile), '..', 'remote')
+        if not os.path.exists(remotePath):
+            os.makedirs(remotePath)
+        shutil.copyfile(localLargeFile, os.path.join(remotePath, os.path.basename(localLargeFile)))
+
+class GitLFS(LargeFileSystem):
+    """Git LFS as backend for the git-p4 large file system.
+       See https://git-lfs.github.com/ for details."""
+
+    def __init__(self, *args):
+        LargeFileSystem.__init__(self, *args)
+        self.baseGitAttributes = []
+
+    def generatePointer(self, contentFile):
+        """Generate a Git LFS pointer for the content. Return LFS Pointer file
+           mode and content which is stored in the Git repository instead of
+           the actual content. Return also the new location of the actual
+           content.
+           """
+        pointerProcess = subprocess.Popen(
+            ['git', 'lfs', 'pointer', '--file=' + contentFile],
+            stdout=subprocess.PIPE
+        )
+        pointerFile = pointerProcess.stdout.read()
+        if pointerProcess.wait():
+            os.remove(contentFile)
+            die('git-lfs pointer command failed. Did you install the extension?')
+        pointerContents = [i+'\n' for i in pointerFile.split('\n')[2:][:-1]]
+        oid = pointerContents[1].split(' ')[1].split(':')[1][:-1]
+        localLargeFile = os.path.join(
+            os.getcwd(),
+            '.git', 'lfs', 'objects', oid[:2], oid[2:4],
+            oid,
+        )
+        # LFS Spec states that pointer files should not have the executable bit set.
+        gitMode = '100644'
+        return (gitMode, pointerContents, localLargeFile)
+
+    def pushFile(self, localLargeFile):
+        uploadProcess = subprocess.Popen(
+            ['git', 'lfs', 'push', '--object-id', 'origin', os.path.basename(localLargeFile)]
+        )
+        if uploadProcess.wait():
+            die('git-lfs push command failed. Did you define a remote?')
+
+    def generateGitAttributes(self):
+        return (
+            self.baseGitAttributes +
+            [
+                '\n',
+                '#\n',
+                '# Git LFS (see https://git-lfs.github.com/)\n',
+                '#\n',
+            ] +
+            ['*.' + f.replace(' ', '[[:space:]]') + ' filter=lfs -text\n'
+                for f in sorted(gitConfigList('git-p4.largeFileExtensions'))
+            ] +
+            ['/' + f.replace(' ', '[[:space:]]') + ' filter=lfs -text\n'
+                for f in sorted(self.largeFiles) if not self.hasLargeFileExtension(f)
+            ]
+        )
+
+    def addLargeFile(self, relPath):
+        LargeFileSystem.addLargeFile(self, relPath)
+        self.writeToGitStream('100644', '.gitattributes', self.generateGitAttributes())
+
+    def removeLargeFile(self, relPath):
+        LargeFileSystem.removeLargeFile(self, relPath)
+        self.writeToGitStream('100644', '.gitattributes', self.generateGitAttributes())
+
+    def processContent(self, git_mode, relPath, contents):
+        if relPath == '.gitattributes':
+            self.baseGitAttributes = contents
+            return (git_mode, self.generateGitAttributes())
+        else:
+            return LargeFileSystem.processContent(self, git_mode, relPath, contents)
+
 class Command:
     def __init__(self):
         self.usage = "usage: %prog [options]"
@@ -1080,6 +1287,9 @@ def __init__(self):
         self.p4HasMoveCommand = p4_has_move_command()
         self.branch = None
 
+        if gitConfig('git-p4.largeFileSystem'):
+            die("Large file system not supported for git-p4 submit command. Please remove it from config.")
+
     def check(self):
         if len(p4CmdList("opened ...")) > 0:
             die("You have files opened with perforce! Close them before starting the sync.")
@@ -1246,6 +1456,8 @@ def prepareSubmitTemplate(self):
            Remove lines in the Files section that show changes to files
            outside the depot path we're committing into."""
 
+        [upstream, settings] = findUpstreamBranchPoint()
+
         template = ""
         inFilesSection = False
         for line in p4_read_pipe_lines(['change', '-o']):
@@ -1258,8 +1470,13 @@ def prepareSubmitTemplate(self):
                     lastTab = path.rfind("\t")
                     if lastTab != -1:
                         path = path[:lastTab]
-                        if not p4PathStartsWith(path, self.depotPath):
-                            continue
+                        if settings.has_key('depot-paths'):
+                            if not [p for p in settings['depot-paths']
+                                    if p4PathStartsWith(path, p)]:
+                                continue
+                        else:
+                            if not p4PathStartsWith(path, self.depotPath):
+                                continue
                 else:
                     inFilesSection = False
             else:
@@ -1536,44 +1753,47 @@ def applyCommit(self, id):
         #
         # Let the user edit the change description, then submit it.
         #
-        if self.edit_template(fileName):
-            # read the edited message and submit
-            ret = True
-            tmpFile = open(fileName, "rb")
-            message = tmpFile.read()
-            tmpFile.close()
-            if self.isWindows:
-                message = message.replace("\r\n", "\n")
-            submitTemplate = message[:message.index(separatorLine)]
-            p4_write_pipe(['submit', '-i'], submitTemplate)
-
-            if self.preserveUser:
-                if p4User:
-                    # Get last changelist number. Cannot easily get it from
-                    # the submit command output as the output is
-                    # unmarshalled.
-                    changelist = self.lastP4Changelist()
-                    self.modifyChangelistUser(changelist, p4User)
-
-            # The rename/copy happened by applying a patch that created a
-            # new file.  This leaves it writable, which confuses p4.
-            for f in pureRenameCopy:
-                p4_sync(f, "-f")
+        submitted = False
 
-        else:
+        try:
+            if self.edit_template(fileName):
+                # read the edited message and submit
+                tmpFile = open(fileName, "rb")
+                message = tmpFile.read()
+                tmpFile.close()
+                if self.isWindows:
+                    message = message.replace("\r\n", "\n")
+                submitTemplate = message[:message.index(separatorLine)]
+                p4_write_pipe(['submit', '-i'], submitTemplate)
+
+                if self.preserveUser:
+                    if p4User:
+                        # Get last changelist number. Cannot easily get it from
+                        # the submit command output as the output is
+                        # unmarshalled.
+                        changelist = self.lastP4Changelist()
+                        self.modifyChangelistUser(changelist, p4User)
+
+                # The rename/copy happened by applying a patch that created a
+                # new file.  This leaves it writable, which confuses p4.
+                for f in pureRenameCopy:
+                    p4_sync(f, "-f")
+                submitted = True
+
+        finally:
             # skip this patch
-            ret = False
-            print "Submission cancelled, undoing p4 changes."
-            for f in editedFiles:
-                p4_revert(f)
-            for f in filesToAdd:
-                p4_revert(f)
-                os.remove(f)
-            for f in filesToDelete:
-                p4_revert(f)
+            if not submitted:
+                print "Submission cancelled, undoing p4 changes."
+                for f in editedFiles:
+                    p4_revert(f)
+                for f in filesToAdd:
+                    p4_revert(f)
+                    os.remove(f)
+                for f in filesToDelete:
+                    p4_revert(f)
 
         os.remove(fileName)
-        return ret
+        return submitted
 
     # Export git tags as p4 labels. Create a p4 label and then tag
     # with that.
@@ -1649,8 +1869,6 @@ def exportGitTags(self, gitTags):
     def run(self, args):
         if len(args) == 0:
             self.master = currentGitBranch()
-            if len(self.master) == 0 or not gitBranchExists("refs/heads/%s" % self.master):
-                die("Detecting current git branch failed!")
         elif len(args) == 1:
             self.master = args[0]
             if not branchExists(self.master):
@@ -1658,9 +1876,10 @@ def run(self, args):
         else:
             return False
 
-        allowSubmit = gitConfig("git-p4.allowSubmit")
-        if len(allowSubmit) > 0 and not self.master in allowSubmit.split(","):
-            die("%s is not in git-p4.allowSubmit" % self.master)
+        if self.master:
+            allowSubmit = gitConfig("git-p4.allowSubmit")
+            if len(allowSubmit) > 0 and not self.master in allowSubmit.split(","):
+                die("%s is not in git-p4.allowSubmit" % self.master)
 
         [upstream, settings] = findUpstreamBranchPoint()
         self.depotPath = settings['depot-paths'][0]
@@ -1728,7 +1947,12 @@ def run(self, args):
         self.check()
 
         commits = []
-        for line in read_pipe_lines(["git", "rev-list", "--no-merges", "%s..%s" % (self.origin, self.master)]):
+        if self.master:
+            commitish = self.master
+        else:
+            commitish = 'HEAD'
+
+        for line in read_pipe_lines(["git", "rev-list", "--no-merges", "%s..%s" % (self.origin, commitish)]):
             commits.append(line.strip())
         commits.reverse()
 
@@ -2030,6 +2254,13 @@ def __init__(self):
         self.clientSpecDirs = None
         self.tempBranches = []
         self.tempBranchLocation = "git-p4-tmp"
+        self.largeFileSystem = None
+
+        if gitConfig('git-p4.largeFileSystem'):
+            largeFileSystemConstructor = globals()[gitConfig('git-p4.largeFileSystem')]
+            self.largeFileSystem = largeFileSystemConstructor(
+                lambda git_mode, relPath, contents: self.writeToGitStream(git_mode, relPath, contents)
+            )
 
         if gitConfig("git-p4.syncFromOrigin") == "false":
             self.syncWithOrigin = False
@@ -2150,13 +2381,22 @@ def splitFilesIntoBranches(self, commit):
 
         return branches
 
+    def writeToGitStream(self, gitMode, relPath, contents):
+        self.gitStream.write('M %s inline %s\n' % (gitMode, relPath))
+        self.gitStream.write('data %d\n' % sum(len(d) for d in contents))
+        for d in contents:
+            self.gitStream.write(d)
+        self.gitStream.write('\n')
+
     # output one file from the P4 stream
     # - helper for streamP4Files
 
     def streamOneP4File(self, file, contents):
         relPath = self.stripRepoPath(file['depotFile'], self.branchPrefixes)
         if verbose:
-            sys.stderr.write("%s\n" % relPath)
+            size = int(self.stream_file['fileSize'])
+            sys.stdout.write('\r%s --> %s (%i MB)\n' % (file['depotFile'], relPath, size/1024/1024))
+            sys.stdout.flush()
 
         (type_base, type_mods) = split_p4_type(file["type"])
 
@@ -2225,24 +2465,31 @@ def streamOneP4File(self, file, contents):
             text = regexp.sub(r'$\1$', text)
             contents = [ text ]
 
-        self.gitStream.write("M %s inline %s\n" % (git_mode, relPath))
+        try:
+            relPath.decode('ascii')
+        except:
+            encoding = 'utf8'
+            if gitConfig('git-p4.pathEncoding'):
+                encoding = gitConfig('git-p4.pathEncoding')
+            relPath = relPath.decode(encoding, 'replace').encode('utf8', 'replace')
+            if self.verbose:
+                print 'Path with non-ASCII characters detected. Used %s to encode: %s ' % (encoding, relPath)
 
-        # total length...
-        length = 0
-        for d in contents:
-            length = length + len(d)
+        if self.largeFileSystem:
+            (git_mode, contents) = self.largeFileSystem.processContent(git_mode, relPath, contents)
 
-        self.gitStream.write("data %d\n" % length)
-        for d in contents:
-            self.gitStream.write(d)
-        self.gitStream.write("\n")
+        self.writeToGitStream(git_mode, relPath, contents)
 
     def streamOneP4Deletion(self, file):
         relPath = self.stripRepoPath(file['path'], self.branchPrefixes)
         if verbose:
-            sys.stderr.write("delete %s\n" % relPath)
+            sys.stdout.write("delete %s\n" % relPath)
+            sys.stdout.flush()
         self.gitStream.write("D %s\n" % relPath)
 
+        if self.largeFileSystem and self.largeFileSystem.isLargeFile(relPath):
+            self.largeFileSystem.removeLargeFile(relPath)
+
     # handle another chunk of streaming data
     def streamP4FilesCb(self, marshalled):
 
@@ -2252,6 +2499,14 @@ def streamP4FilesCb(self, marshalled):
             if marshalled["code"] == "error":
                 if "data" in marshalled:
                     err = marshalled["data"].rstrip()
+
+        if not err and 'fileSize' in self.stream_file:
+            required_bytes = int((4 * int(self.stream_file["fileSize"])) - calcDiskFree())
+            if required_bytes > 0:
+                err = 'Not enough space left on %s! Free at least %i MB.' % (
+                    os.getcwd(), required_bytes/1024/1024
+                )
+
         if err:
             f = None
             if self.stream_have_file_info:
@@ -2280,10 +2535,23 @@ def streamP4FilesCb(self, marshalled):
         # 'data' field we need to append to our array
         for k in marshalled.keys():
             if k == 'data':
+                if 'streamContentSize' not in self.stream_file:
+                    self.stream_file['streamContentSize'] = 0
+                self.stream_file['streamContentSize'] += len(marshalled['data'])
                 self.stream_contents.append(marshalled['data'])
             else:
                 self.stream_file[k] = marshalled[k]
 
+        if (verbose and
+            'streamContentSize' in self.stream_file and
+            'fileSize' in self.stream_file and
+            'depotFile' in self.stream_file):
+            size = int(self.stream_file["fileSize"])
+            if size > 0:
+                progress = 100*self.stream_file['streamContentSize']/size
+                sys.stdout.write('\r%s %d%% (%i MB)' % (self.stream_file['depotFile'], progress, int(size/1024/1024)))
+                sys.stdout.flush()
+
         self.stream_have_file_info = True
 
     # Stream directly from "p4 files" into "git fast-import"
@@ -2293,12 +2561,6 @@ def streamP4Files(self, files):
         filesToDelete = []
 
         for f in files:
-            # if using a client spec, only add the files that have
-            # a path in the client
-            if self.clientSpecDirs:
-                if self.clientSpecDirs.map_in_client(f['path']) == "":
-                    continue
-
             filesForCommit.append(f)
             if f['action'] in self.delete_actions:
                 filesToDelete.append(f)
@@ -2369,25 +2631,41 @@ def streamTag(self, gitStream, labelName, labelDetails, commit, epoch):
         gitStream.write(description)
         gitStream.write("\n")
 
+    def inClientSpec(self, path):
+        if not self.clientSpecDirs:
+            return True
+        inClientSpec = self.clientSpecDirs.map_in_client(path)
+        if not inClientSpec and self.verbose:
+            print('Ignoring file outside of client spec: {0}'.format(path))
+        return inClientSpec
+
+    def hasBranchPrefix(self, path):
+        if not self.branchPrefixes:
+            return True
+        hasPrefix = [p for p in self.branchPrefixes
+                        if p4PathStartsWith(path, p)]
+        if hasPrefix and self.verbose:
+            print('Ignoring file outside of prefix: {0}'.format(path))
+        return hasPrefix
+
     def commit(self, details, files, branch, parent = ""):
         epoch = details["time"]
         author = details["user"]
 
         if self.verbose:
-            print "commit into %s" % branch
-
-        # start with reading files; if that fails, we should not
-        # create a commit.
-        new_files = []
-        for f in files:
-            if [p for p in self.branchPrefixes if p4PathStartsWith(f['path'], p)]:
-                new_files.append (f)
-            else:
-                sys.stderr.write("Ignoring file outside of prefix: %s\n" % f['path'])
+            print('commit into {0}'.format(branch))
 
         if self.clientSpecDirs:
             self.clientSpecDirs.update_client_spec_path_cache(files)
 
+        files = [f for f in files
+            if self.inClientSpec(f['path']) and self.hasBranchPrefix(f['path'])]
+
+        if not files and not gitConfigBool('git-p4.keepEmptyCommits'):
+            print('Ignoring revision {0} as it would produce an empty commit.'
+                .format(details['change']))
+            return
+
         self.gitStream.write("commit %s\n" % branch)
         self.gitStream.write("mark :%s\n" % details["change"])
         self.committedChanges.add(int(details["change"]))
@@ -2411,7 +2689,7 @@ def commit(self, details, files, branch, parent = ""):
                 print "parent %s" % parent
             self.gitStream.write("from %s\n" % parent)
 
-        self.streamP4Files(new_files)
+        self.streamP4Files(files)
         self.gitStream.write("\n")
 
         change = int(details["change"])