#!/usr/bin/env python
#
# git-p4.py -- A tool for bidirectional operation between a Perforce depot and git.
#
# Author: Simon Hausmann <hausmann@kde.org>
# Copyright: 2007 Simon Hausmann <hausmann@kde.org>
#            2007 Trolltech ASA
# License: MIT <http://www.opensource.org/licenses/mit-license.php>
#
# TODO: * Consider making --with-origin the default, assuming that the git
#         protocol is always more efficient. (needs manual testing first :)
#

import optparse, sys, os, marshal, popen2, subprocess, shelve
import tempfile, getopt, sha, os.path, time, platform
from sets import Set;

gitdir = os.environ.get("GIT_DIR", "")

def mypopen(command):
    return os.popen(command, "rb");

def p4CmdList(cmd):
    cmd = "p4 -G %s" % cmd
    pipe = os.popen(cmd, "rb")

    result = []
    try:
        while True:
            entry = marshal.load(pipe)
            result.append(entry)
    except EOFError:
        pass
    exitCode = pipe.close()
    if exitCode != None:
        result["p4ExitCode"] = exitCode

    return result

def p4Cmd(cmd):
    list = p4CmdList(cmd)
    result = {}
    for entry in list:
        result.update(entry)
    return result;

def p4Where(depotPath):
    if not depotPath.endswith("/"):
        depotPath += "/"
    output = p4Cmd("where %s..." % depotPath)
    if output["code"] == "error":
        return ""
    clientPath = ""
    if "path" in output:
        clientPath = output.get("path")
    elif "data" in output:
        data = output.get("data")
        lastSpace = data.rfind(" ")
        clientPath = data[lastSpace + 1:]

    if clientPath.endswith("..."):
        clientPath = clientPath[:-3]
    return clientPath

def die(msg):
    sys.stderr.write(msg + "\n")
    sys.exit(1)

def currentGitBranch():
    return mypopen("git name-rev HEAD").read().split(" ")[1][:-1]

def isValidGitDir(path):
    if os.path.exists(path + "/HEAD") and os.path.exists(path + "/refs") and os.path.exists(path + "/objects"):
        return True;
    return False

def parseRevision(ref):
    return mypopen("git rev-parse %s" % ref).read()[:-1]

def system(cmd):
    if os.system(cmd) != 0:
        die("command failed: %s" % cmd)

def extractLogMessageFromGitCommit(commit):
    logMessage = ""
    foundTitle = False
    for log in mypopen("git cat-file commit %s" % commit).readlines():
       if not foundTitle:
           if len(log) == 1:
               foundTitle = True
           continue

       logMessage += log
    return logMessage

def extractDepotPathAndChangeFromGitLog(log):
    values = {}
    for line in log.split("\n"):
        line = line.strip()
        if line.startswith("[git-p4:") and line.endswith("]"):
            line = line[8:-1].strip()
            for assignment in line.split(":"):
                variable = assignment.strip()
                value = ""
                equalPos = assignment.find("=")
                if equalPos != -1:
                    variable = assignment[:equalPos].strip()
                    value = assignment[equalPos + 1:].strip()
                    if value.startswith("\"") and value.endswith("\""):
                        value = value[1:-1]
                values[variable] = value

    return values.get("depot-path"), values.get("change")

def gitBranchExists(branch):
    proc = subprocess.Popen(["git", "rev-parse", branch], stderr=subprocess.PIPE, stdout=subprocess.PIPE);
    return proc.wait() == 0;

class Command:
    def __init__(self):
        self.usage = "usage: %prog [options]"
        self.needsGit = True

class P4Debug(Command):
    def __init__(self):
        Command.__init__(self)
        self.options = [
        ]
        self.description = "A tool to debug the output of p4 -G."
        self.needsGit = False

    def run(self, args):
        for output in p4CmdList(" ".join(args)):
            print output
        return True

class P4RollBack(Command):
    def __init__(self):
        Command.__init__(self)
        self.options = [
            optparse.make_option("--verbose", dest="verbose", action="store_true"),
            optparse.make_option("--local", dest="rollbackLocalBranches", action="store_true")
        ]
        self.description = "A tool to debug the multi-branch import. Don't use :)"
        self.verbose = False
        self.rollbackLocalBranches = False

    def run(self, args):
        if len(args) != 1:
            return False
        maxChange = int(args[0])

        if self.rollbackLocalBranches:
            refPrefix = "refs/heads/"
            lines = mypopen("git rev-parse --symbolic --branches").readlines()
        else:
            refPrefix = "refs/remotes/"
            lines = mypopen("git rev-parse --symbolic --remotes").readlines()

        for line in lines:
            if self.rollbackLocalBranches or (line.startswith("p4/") and line != "p4/HEAD\n"):
                ref = refPrefix + line[:-1]
                log = extractLogMessageFromGitCommit(ref)
                depotPath, change = extractDepotPathAndChangeFromGitLog(log)
                changed = False

                if len(p4Cmd("changes -m 1 %s...@%s" % (depotPath, maxChange))) == 0:
                    print "Branch %s did not exist at change %s, deleting." % (ref, maxChange)
                    system("git update-ref -d %s `git rev-parse %s`" % (ref, ref))
                    continue

                while len(change) > 0 and int(change) > maxChange:
                    changed = True
                    if self.verbose:
                        print "%s is at %s ; rewinding towards %s" % (ref, change, maxChange)
                    system("git update-ref %s \"%s^\"" % (ref, ref))
                    log = extractLogMessageFromGitCommit(ref)
                    depotPath, change = extractDepotPathAndChangeFromGitLog(log)

                if changed:
                    print "%s rewound to %s" % (ref, change)

        return True

class P4Submit(Command):
    def __init__(self):
        Command.__init__(self)
        self.options = [
                optparse.make_option("--continue", action="store_false", dest="firstTime"),
                optparse.make_option("--origin", dest="origin"),
                optparse.make_option("--reset", action="store_true", dest="reset"),
                optparse.make_option("--log-substitutions", dest="substFile"),
                optparse.make_option("--noninteractive", action="store_false"),
                optparse.make_option("--dry-run", action="store_true"),
                optparse.make_option("--direct", dest="directSubmit", action="store_true"),
        ]
        self.description = "Submit changes from git to the perforce depot."
        self.usage += " [name of git branch to submit into perforce depot]"
        self.firstTime = True
        self.reset = False
        self.interactive = True
        self.dryRun = False
        self.substFile = ""
        self.firstTime = True
        self.origin = ""
        self.directSubmit = False

        self.logSubstitutions = {}
        self.logSubstitutions["<enter description here>"] = "%log%"
        self.logSubstitutions["\tDetails:"] = "\tDetails:  %log%"

    def check(self):
        if len(p4CmdList("opened ...")) > 0:
            die("You have files opened with perforce! Close them before starting the sync.")

    def start(self):
        if len(self.config) > 0 and not self.reset:
            die("Cannot start sync. Previous sync config found at %s\nIf you want to start submitting again from scratch maybe you want to call git-p4 submit --reset" % self.configFile)

        commits = []
        if self.directSubmit:
            commits.append("0")
        else:
            for line in mypopen("git rev-list --no-merges %s..%s" % (self.origin, self.master)).readlines():
                commits.append(line[:-1])
            commits.reverse()

        self.config["commits"] = commits

    def prepareLogMessage(self, template, message):
        result = ""

        for line in template.split("\n"):
            if line.startswith("#"):
                result += line + "\n"
                continue

            substituted = False
            for key in self.logSubstitutions.keys():
                if line.find(key) != -1:
                    value = self.logSubstitutions[key]
                    value = value.replace("%log%", message)
                    if value != "@remove@":
                        result += line.replace(key, value) + "\n"
                    substituted = True
                    break

            if not substituted:
                result += line + "\n"

        return result

    def apply(self, id):
        if self.directSubmit:
            print "Applying local change in working directory/index"
            diff = self.diffStatus
        else:
            print "Applying %s" % (mypopen("git log --max-count=1 --pretty=oneline %s" % id).read())
            diff = mypopen("git diff-tree -r --name-status \"%s^\" \"%s\"" % (id, id)).readlines()
        filesToAdd = set()
        filesToDelete = set()
        editedFiles = set()
        for line in diff:
            modifier = line[0]
            path = line[1:].strip()
            if modifier == "M":
                system("p4 edit \"%s\"" % path)
                editedFiles.add(path)
            elif modifier == "A":
                filesToAdd.add(path)
                if path in filesToDelete:
                    filesToDelete.remove(path)
            elif modifier == "D":
                filesToDelete.add(path)
                if path in filesToAdd:
                    filesToAdd.remove(path)
            else:
                die("unknown modifier %s for %s" % (modifier, path))

        if self.directSubmit:
            diffcmd = "cat \"%s\"" % self.diffFile
        else:
            diffcmd = "git format-patch -k --stdout \"%s^\"..\"%s\"" % (id, id)
        patchcmd = diffcmd + " | git apply "
        tryPatchCmd = patchcmd + "--check -"
        applyPatchCmd = patchcmd + "--check --apply -"

        if os.system(tryPatchCmd) != 0:
            print "Unfortunately applying the change failed!"
            print "What do you want to do?"
            response = "x"
            while response != "s" and response != "a" and response != "w":
                response = raw_input("[s]kip this patch / [a]pply the patch forcibly and with .rej files / [w]rite the patch to a file (patch.txt) ")
            if response == "s":
                print "Skipping! Good luck with the next patches..."
                return
            elif response == "a":
                os.system(applyPatchCmd)
                if len(filesToAdd) > 0:
                    print "You may also want to call p4 add on the following files:"
                    print " ".join(filesToAdd)
                if len(filesToDelete):
                    print "The following files should be scheduled for deletion with p4 delete:"
                    print " ".join(filesToDelete)
                die("Please resolve and submit the conflict manually and continue afterwards with git-p4 submit --continue")
            elif response == "w":
                system(diffcmd + " > patch.txt")
                print "Patch saved to patch.txt in %s !" % self.clientPath
                die("Please resolve and submit the conflict manually and continue afterwards with git-p4 submit --continue")

        system(applyPatchCmd)

        for f in filesToAdd:
            system("p4 add %s" % f)
        for f in filesToDelete:
            system("p4 revert %s" % f)
            system("p4 delete %s" % f)

        logMessage = ""
        if not self.directSubmit:
            logMessage = extractLogMessageFromGitCommit(id)
            logMessage = logMessage.replace("\n", "\n\t")
            logMessage = logMessage[:-1]

        template = mypopen("p4 change -o").read()

        if self.interactive:
            submitTemplate = self.prepareLogMessage(template, logMessage)
            diff = mypopen("p4 diff -du ...").read()

            for newFile in filesToAdd:
                diff += "==== new file ====\n"
                diff += "--- /dev/null\n"
                diff += "+++ %s\n" % newFile
                f = open(newFile, "r")
                for line in f.readlines():
                    diff += "+" + line
                f.close()

            separatorLine = "######## everything below this line is just the diff #######"
            if platform.system() == "Windows":
                separatorLine += "\r"
            separatorLine += "\n"

            response = "e"
            firstIteration = True
            while response == "e":
                if not firstIteration:
                    response = raw_input("Do you want to submit this change? [y]es/[e]dit/[n]o/[s]kip ")
                firstIteration = False
                if response == "e":
                    [handle, fileName] = tempfile.mkstemp()
                    tmpFile = os.fdopen(handle, "w+")
                    tmpFile.write(submitTemplate + separatorLine + diff)
                    tmpFile.close()
                    defaultEditor = "vi"
                    if platform.system() == "Windows":
                        defaultEditor = "notepad"
                    editor = os.environ.get("EDITOR", defaultEditor);
                    system(editor + " " + fileName)
                    tmpFile = open(fileName, "rb")
                    message = tmpFile.read()
                    tmpFile.close()
                    os.remove(fileName)
                    submitTemplate = message[:message.index(separatorLine)]

            if response == "y" or response == "yes":
               if self.dryRun:
                   print submitTemplate
                   raw_input("Press return to continue...")
               else:
                   if self.directSubmit:
                       print "Submitting to git first"
                       os.chdir(self.oldWorkingDirectory)
                       pipe = os.popen("git commit -a -F -", "wb")
                       pipe.write(submitTemplate)
                       pipe.close()
                       os.chdir(self.clientPath)

                   pipe = os.popen("p4 submit -i", "wb")
                   pipe.write(submitTemplate)
                   pipe.close()
            elif response == "s":
                for f in editedFiles:
                    system("p4 revert \"%s\"" % f);
                for f in filesToAdd:
                    system("p4 revert \"%s\"" % f);
                    system("rm %s" %f)
                for f in filesToDelete:
                    system("p4 delete \"%s\"" % f);
                return
            else:
                print "Not submitting!"
                self.interactive = False
        else:
            fileName = "submit.txt"
            file = open(fileName, "w+")
            file.write(self.prepareLogMessage(template, logMessage))
            file.close()
            print "Perforce submit template written as %s. Please review/edit and then use p4 submit -i < %s to submit directly!" % (fileName, fileName)

    def run(self, args):
        global gitdir
        # make gitdir absolute so we can cd out into the perforce checkout
        gitdir = os.path.abspath(gitdir)
        os.environ["GIT_DIR"] = gitdir

        if len(args) == 0:
            self.master = currentGitBranch()
            if len(self.master) == 0 or not os.path.exists("%s/refs/heads/%s" % (gitdir, self.master)):
                die("Detecting current git branch failed!")
        elif len(args) == 1:
            self.master = args[0]
        else:
            return False

        depotPath = ""
        if gitBranchExists("p4"):
            [depotPath, dummy] = extractDepotPathAndChangeFromGitLog(extractLogMessageFromGitCommit("p4"))
        if len(depotPath) == 0 and gitBranchExists("origin"):
            [depotPath, dummy] = extractDepotPathAndChangeFromGitLog(extractLogMessageFromGitCommit("origin"))

        if len(depotPath) == 0:
            print "Internal error: cannot locate perforce depot path from existing branches"
            sys.exit(128)

        self.clientPath = p4Where(depotPath)

        if len(self.clientPath) == 0:
            print "Error: Cannot locate perforce checkout of %s in client view" % depotPath
            sys.exit(128)

        print "Perforce checkout for depot path %s located at %s" % (depotPath, self.clientPath)
        self.oldWorkingDirectory = os.getcwd()

        if self.directSubmit:
            self.diffStatus = mypopen("git diff -r --name-status HEAD").readlines()
            if len(self.diffStatus) == 0:
                print "No changes in working directory to submit."
                return True
            patch = mypopen("git diff -p --binary --diff-filter=ACMRTUXB HEAD").read()
            self.diffFile = gitdir + "/p4-git-diff"
            f = open(self.diffFile, "wb")
            f.write(patch)
            f.close();

        os.chdir(self.clientPath)
        response = raw_input("Do you want to sync %s with p4 sync? [y]es/[n]o " % self.clientPath)
        if response == "y" or response == "yes":
            system("p4 sync ...")

        if len(self.origin) == 0:
            if gitBranchExists("p4"):
                self.origin = "p4"
            else:
                self.origin = "origin"

        if self.reset:
            self.firstTime = True

        if len(self.substFile) > 0:
            for line in open(self.substFile, "r").readlines():
                tokens = line[:-1].split("=")
                self.logSubstitutions[tokens[0]] = tokens[1]

        self.check()
        self.configFile = gitdir + "/p4-git-sync.cfg"
        self.config = shelve.open(self.configFile, writeback=True)

        if self.firstTime:
            self.start()

        commits = self.config.get("commits", [])

        while len(commits) > 0:
            self.firstTime = False
            commit = commits[0]
            commits = commits[1:]
            self.config["commits"] = commits
            self.apply(commit)
            if not self.interactive:
                break

        self.config.close()

        if self.directSubmit:
            os.remove(self.diffFile)

        if len(commits) == 0:
            if self.firstTime:
                print "No changes found to apply between %s and current HEAD" % self.origin
            else:
                print "All changes applied!"
                os.chdir(self.oldWorkingDirectory)
                response = raw_input("Do you want to sync from Perforce now using git-p4 rebase? [y]es/[n]o ")
                if response == "y" or response == "yes":
                    rebase = P4Rebase()
                    rebase.run([])
            os.remove(self.configFile)

        return True

class P4Sync(Command):
    def __init__(self):
        Command.__init__(self)
        self.options = [
                optparse.make_option("--branch", dest="branch"),
                optparse.make_option("--detect-branches", dest="detectBranches", action="store_true"),
                optparse.make_option("--changesfile", dest="changesFile"),
                optparse.make_option("--silent", dest="silent", action="store_true"),
                optparse.make_option("--detect-labels", dest="detectLabels", action="store_true"),
                optparse.make_option("--with-origin", dest="syncWithOrigin", action="store_true"),
                optparse.make_option("--verbose", dest="verbose", action="store_true"),
                optparse.make_option("--import-local", dest="importIntoRemotes", action="store_false"),
                optparse.make_option("--max-changes", dest="maxChanges")
        ]
        self.description = """Imports from Perforce into a git repository.\n
    example:
    //depot/my/project/ -- to import the current head
    //depot/my/project/@all -- to import everything
    //depot/my/project/@1,6 -- to import only from revision 1 to 6

    (a ... is not needed in the path p4 specification, it's added implicitly)"""

        self.usage += " //depot/path[@revRange]"

        self.silent = False
        self.createdBranches = Set()
        self.committedChanges = Set()
        self.branch = ""
        self.detectBranches = False
        self.detectLabels = False
        self.changesFile = ""
        self.syncWithOrigin = False
        self.verbose = False
        self.importIntoRemotes = True
        self.maxChanges = ""

    def p4File(self, depotPath):
        return os.popen("p4 print -q \"%s\"" % depotPath, "rb").read()

    def extractFilesFromCommit(self, commit):
        files = []
        fnum = 0
        while commit.has_key("depotFile%s" % fnum):
            path =  commit["depotFile%s" % fnum]
            if not path.startswith(self.depotPath):
    #            if not self.silent:
    #                print "\nchanged files: ignoring path %s outside of %s in change %s" % (path, self.depotPath, change)
                fnum = fnum + 1
                continue

            file = {}
            file["path"] = path
            file["rev"] = commit["rev%s" % fnum]
            file["action"] = commit["action%s" % fnum]
            file["type"] = commit["type%s" % fnum]
            files.append(file)
            fnum = fnum + 1
        return files

    def splitFilesIntoBranches(self, commit):
        branches = {}

        fnum = 0
        while commit.has_key("depotFile%s" % fnum):
            path =  commit["depotFile%s" % fnum]
            if not path.startswith(self.depotPath):
    #            if not self.silent:
    #                print "\nchanged files: ignoring path %s outside of %s in change %s" % (path, self.depotPath, change)
                fnum = fnum + 1
                continue

            file = {}
            file["path"] = path
            file["rev"] = commit["rev%s" % fnum]
            file["action"] = commit["action%s" % fnum]
            file["type"] = commit["type%s" % fnum]
            fnum = fnum + 1

            relPath = path[len(self.depotPath):]

            for branch in self.knownBranches.keys():
                if relPath.startswith(branch + "/"): # add a trailing slash so that a commit into qt/4.2foo doesn't end up in qt/4.2
                    if branch not in branches:
                        branches[branch] = []
                    branches[branch].append(file)

        return branches

    def commit(self, details, files, branch, branchPrefix, parent = ""):
        epoch = details["time"]
        author = details["user"]

        if self.verbose:
            print "commit into %s" % branch

        self.gitStream.write("commit %s\n" % branch)
    #    gitStream.write("mark :%s\n" % details["change"])
        self.committedChanges.add(int(details["change"]))
        committer = ""
        if author not in self.users:
            self.getUserMapFromPerforceServer()
        if author in self.users:
            committer = "%s %s %s" % (self.users[author], epoch, self.tz)
        else:
            committer = "%s <a@b> %s %s" % (author, epoch, self.tz)

        self.gitStream.write("committer %s\n" % committer)

        self.gitStream.write("data <<EOT\n")
        self.gitStream.write(details["desc"])
        self.gitStream.write("\n[git-p4: depot-path = \"%s\": change = %s]\n" % (branchPrefix, details["change"]))
        self.gitStream.write("EOT\n\n")

        if len(parent) > 0:
            if self.verbose:
                print "parent %s" % parent
            self.gitStream.write("from %s\n" % parent)

        for file in files:
            path = file["path"]
            if not path.startswith(branchPrefix):
    #            if not silent:
    #                print "\nchanged files: ignoring path %s outside of branch prefix %s in change %s" % (path, branchPrefix, details["change"])
                continue
            rev = file["rev"]
            depotPath = path + "#" + rev
            relPath = path[len(branchPrefix):]
            action = file["action"]

            if file["type"] == "apple":
                print "\nfile %s is a strange apple file that forks. Ignoring!" % path
                continue

            if action == "delete":
                self.gitStream.write("D %s\n" % relPath)
            else:
                mode = 644
                if file["type"].startswith("x"):
                    mode = 755

                data = self.p4File(depotPath)

                self.gitStream.write("M %s inline %s\n" % (mode, relPath))
                self.gitStream.write("data %s\n" % len(data))
                self.gitStream.write(data)
                self.gitStream.write("\n")

        self.gitStream.write("\n")

        change = int(details["change"])

        if self.labels.has_key(change):
            label = self.labels[change]
            labelDetails = label[0]
            labelRevisions = label[1]
            if self.verbose:
                print "Change %s is labelled %s" % (change, labelDetails)

            files = p4CmdList("files %s...@%s" % (branchPrefix, change))

            if len(files) == len(labelRevisions):

                cleanedFiles = {}
                for info in files:
                    if info["action"] == "delete":
                        continue
                    cleanedFiles[info["depotFile"]] = info["rev"]

                if cleanedFiles == labelRevisions:
                    self.gitStream.write("tag tag_%s\n" % labelDetails["label"])
                    self.gitStream.write("from %s\n" % branch)

                    owner = labelDetails["Owner"]
                    tagger = ""
                    if author in self.users:
                        tagger = "%s %s %s" % (self.users[owner], epoch, self.tz)
                    else:
                        tagger = "%s <a@b> %s %s" % (owner, epoch, self.tz)
                    self.gitStream.write("tagger %s\n" % tagger)
                    self.gitStream.write("data <<EOT\n")
                    self.gitStream.write(labelDetails["Description"])
                    self.gitStream.write("EOT\n\n")

                else:
                    if not self.silent:
                        print "Tag %s does not match with change %s: files do not match." % (labelDetails["label"], change)

            else:
                if not self.silent:
                    print "Tag %s does not match with change %s: file count is different." % (labelDetails["label"], change)

    def getUserMapFromPerforceServer(self):
        self.users = {}

        for output in p4CmdList("users"):
            if not output.has_key("User"):
                continue
            self.users[output["User"]] = output["FullName"] + " <" + output["Email"] + ">"

        cache = open(gitdir + "/p4-usercache.txt", "wb")
        for user in self.users.keys():
            cache.write("%s\t%s\n" % (user, self.users[user]))
        cache.close();

    def loadUserMapFromCache(self):
        self.users = {}
        try:
            cache = open(gitdir + "/p4-usercache.txt", "rb")
            lines = cache.readlines()
            cache.close()
            for line in lines:
                entry = line[:-1].split("\t")
                self.users[entry[0]] = entry[1]
        except IOError:
            self.getUserMapFromPerforceServer()

    def getLabels(self):
        self.labels = {}

        l = p4CmdList("labels %s..." % self.depotPath)
        if len(l) > 0 and not self.silent:
            print "Finding files belonging to labels in %s" % self.depotPath

        for output in l:
            label = output["label"]
            revisions = {}
            newestChange = 0
            if self.verbose:
                print "Querying files for label %s" % label
            for file in p4CmdList("files %s...@%s" % (self.depotPath, label)):
                revisions[file["depotFile"]] = file["rev"]
                change = int(file["change"])
                if change > newestChange:
                    newestChange = change

            self.labels[newestChange] = [output, revisions]

        if self.verbose:
            print "Label changes: %s" % self.labels.keys()

    def getBranchMapping(self):
        self.projectName = self.depotPath[self.depotPath[:-1].rfind("/") + 1:]

        for info in p4CmdList("branches"):
            details = p4Cmd("branch -o %s" % info["branch"])
            viewIdx = 0
            while details.has_key("View%s" % viewIdx):
                paths = details["View%s" % viewIdx].split(" ")
                viewIdx = viewIdx + 1
                # require standard //depot/foo/... //depot/bar/... mapping
                if len(paths) != 2 or not paths[0].endswith("/...") or not paths[1].endswith("/..."):
                    continue
                source = paths[0]
                destination = paths[1]
                if source.startswith(self.depotPath) and destination.startswith(self.depotPath):
                    source = source[len(self.depotPath):-4]
                    destination = destination[len(self.depotPath):-4]
                    if destination not in self.knownBranches:
                        self.knownBranches[destination] = source
                    if source not in self.knownBranches:
                        self.knownBranches[source] = source

    def listExistingP4GitBranches(self):
        self.p4BranchesInGit = []

        cmdline = "git rev-parse --symbolic "
        if self.importIntoRemotes:
            cmdline += " --remotes"
        else:
            cmdline += " --branches"

        for line in mypopen(cmdline).readlines():
            if self.importIntoRemotes and ((not line.startswith("p4/")) or line == "p4/HEAD\n"):
                continue
            if self.importIntoRemotes:
                # strip off p4
                branch = line[3:-1]
            else:
                branch = line[:-1]
            self.p4BranchesInGit.append(branch)
            self.initialParents[self.refPrefix + branch] = parseRevision(line[:-1])

    def run(self, args):
        self.depotPath = ""
        self.changeRange = ""
        self.initialParent = ""
        self.previousDepotPath = ""
        # map from branch depot path to parent branch
        self.knownBranches = {}
        self.initialParents = {}

        if self.importIntoRemotes:
            self.refPrefix = "refs/remotes/p4/"
        else:
            self.refPrefix = "refs/heads/"

        createP4HeadRef = False;

        if self.syncWithOrigin and gitBranchExists("origin") and gitBranchExists(self.refPrefix + "master") and not self.detectBranches and self.importIntoRemotes:
            ### needs to be ported to multi branch import

            print "Syncing with origin first as requested by calling git fetch origin"
            system("git fetch origin")
            [originPreviousDepotPath, originP4Change] = extractDepotPathAndChangeFromGitLog(extractLogMessageFromGitCommit("origin"))
            [p4PreviousDepotPath, p4Change] = extractDepotPathAndChangeFromGitLog(extractLogMessageFromGitCommit("p4"))
            if len(originPreviousDepotPath) > 0 and len(originP4Change) > 0 and len(p4Change) > 0:
                if originPreviousDepotPath == p4PreviousDepotPath:
                    originP4Change = int(originP4Change)
                    p4Change = int(p4Change)
                    if originP4Change > p4Change:
                        print "origin (%s) is newer than p4 (%s). Updating p4 branch from origin." % (originP4Change, p4Change)
                        system("git update-ref " + self.refPrefix + "master origin");
                else:
                    print "Cannot sync with origin. It was imported from %s while remotes/p4 was imported from %s" % (originPreviousDepotPath, p4PreviousDepotPath)

        if len(self.branch) == 0:
            self.branch = self.refPrefix + "master"
            if gitBranchExists("refs/heads/p4") and self.importIntoRemotes:
                system("git update-ref %s refs/heads/p4" % self.branch)
                system("git branch -D p4");
            # create it /after/ importing, when master exists
            if not gitBranchExists(self.refPrefix + "HEAD") and self.importIntoRemotes:
                createP4HeadRef = True

        # this needs to be called after the conversion from heads/p4 to remotes/p4/master
        self.listExistingP4GitBranches()
        if len(self.p4BranchesInGit) > 1 and not self.silent:
            print "Importing from/into multiple branches"
            self.detectBranches = True

        if len(args) == 0:
            if not gitBranchExists(self.branch) and gitBranchExists("origin") and not self.detectBranches:
                ### needs to be ported to multi branch import
                if not self.silent:
                    print "Creating %s branch in git repository based on origin" % self.branch
                branch = self.branch
                if not branch.startswith("refs"):
                    branch = "refs/heads/" + branch
                system("git update-ref %s origin" % branch)

            if self.verbose:
                print "branches: %s" % self.p4BranchesInGit

            p4Change = 0
            for branch in self.p4BranchesInGit:
                depotPath, change = extractDepotPathAndChangeFromGitLog(extractLogMessageFromGitCommit(self.refPrefix + branch))

                if self.verbose:
                    print "path %s change %s" % (depotPath, change)

                if len(depotPath) > 0 and len(change) > 0:
                    change = int(change) + 1
                    p4Change = max(p4Change, change)

                    if len(self.previousDepotPath) == 0:
                        self.previousDepotPath = depotPath
                    else:
                        i = 0
                        l = min(len(self.previousDepotPath), len(depotPath))
                        while i < l and self.previousDepotPath[i] == depotPath[i]:
                            i = i + 1
                        self.previousDepotPath = self.previousDepotPath[:i]

            if p4Change > 0:
                self.depotPath = self.previousDepotPath
                self.changeRange = "@%s,#head" % p4Change
                self.initialParent = parseRevision(self.branch)
                if not self.silent and not self.detectBranches:
                    print "Performing incremental import into %s git branch" % self.branch

        if not self.branch.startswith("refs/"):
            self.branch = "refs/heads/" + self.branch

        if len(self.depotPath) != 0:
            self.depotPath = self.depotPath[:-1]

        if len(args) == 0 and len(self.depotPath) != 0:
            if not self.silent:
                print "Depot path: %s" % self.depotPath
        elif len(args) != 1:
            return False
        else:
            if len(self.depotPath) != 0 and self.depotPath != args[0]:
                print "previous import used depot path %s and now %s was specified. this doesn't work!" % (self.depotPath, args[0])
                sys.exit(1)
            self.depotPath = args[0]

        self.revision = ""
        self.users = {}

        if self.depotPath.find("@") != -1:
            atIdx = self.depotPath.index("@")
            self.changeRange = self.depotPath[atIdx:]
            if self.changeRange == "@all":
                self.changeRange = ""
            elif self.changeRange.find(",") == -1:
                self.revision = self.changeRange
                self.changeRange = ""
            self.depotPath = self.depotPath[0:atIdx]
        elif self.depotPath.find("#") != -1:
            hashIdx = self.depotPath.index("#")
            self.revision = self.depotPath[hashIdx:]
            self.depotPath = self.depotPath[0:hashIdx]
        elif len(self.previousDepotPath) == 0:
            self.revision = "#head"

        if self.depotPath.endswith("..."):
            self.depotPath = self.depotPath[:-3]

        if not self.depotPath.endswith("/"):
            self.depotPath += "/"

        self.loadUserMapFromCache()
        self.labels = {}
        if self.detectLabels:
            self.getLabels();

        if self.detectBranches:
            self.getBranchMapping();
            if self.verbose:
                print "p4-git branches: %s" % self.p4BranchesInGit
                print "initial parents: %s" % self.initialParents
            for b in self.p4BranchesInGit:
                if b != "master":
                    b = b[len(self.projectName):]
                self.createdBranches.add(b)

        self.tz = "%+03d%02d" % (- time.timezone / 3600, ((- time.timezone % 3600) / 60))

        importProcess = subprocess.Popen(["git", "fast-import"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE);
        self.gitOutput = importProcess.stdout
        self.gitStream = importProcess.stdin
        self.gitError = importProcess.stderr

        if len(self.revision) > 0:
            print "Doing initial import of %s from revision %s" % (self.depotPath, self.revision)

            details = { "user" : "git perforce import user", "time" : int(time.time()) }
            details["desc"] = "Initial import of %s from the state at revision %s" % (self.depotPath, self.revision)
            details["change"] = self.revision
            newestRevision = 0

            fileCnt = 0
            for info in p4CmdList("files %s...%s" % (self.depotPath, self.revision)):
                change = int(info["change"])
                if change > newestRevision:
                    newestRevision = change

                if info["action"] == "delete":
                    # don't increase the file cnt, otherwise details["depotFile123"] will have gaps!
                    #fileCnt = fileCnt + 1
                    continue

                for prop in [ "depotFile", "rev", "action", "type" ]:
                    details["%s%s" % (prop, fileCnt)] = info[prop]

                fileCnt = fileCnt + 1

            details["change"] = newestRevision

            try:
                self.commit(details, self.extractFilesFromCommit(details), self.branch, self.depotPath)
            except IOError:
                print "IO error with git fast-import. Is your git version recent enough?"
                print self.gitError.read()

        else:
            changes = []

            if len(self.changesFile) > 0:
                output = open(self.changesFile).readlines()
                changeSet = Set()
                for line in output:
                    changeSet.add(int(line))

                for change in changeSet:
                    changes.append(change)

                changes.sort()
            else:
                if self.verbose:
                    print "Getting p4 changes for %s...%s" % (self.depotPath, self.changeRange)
                output = mypopen("p4 changes %s...%s" % (self.depotPath, self.changeRange)).readlines()

                for line in output:
                    changeNum = line.split(" ")[1]
                    changes.append(changeNum)

                changes.reverse()

                if len(self.maxChanges) > 0:
                    changes = changes[0:min(int(self.maxChanges), len(changes))]

            if len(changes) == 0:
                if not self.silent:
                    print "No changes to import!"
                return True

            self.updatedBranches = set()

            cnt = 1
            for change in changes:
                description = p4Cmd("describe %s" % change)

                if not self.silent:
                    sys.stdout.write("\rImporting revision %s (%s%%)" % (change, cnt * 100 / len(changes)))
                    sys.stdout.flush()
                cnt = cnt + 1

                try:
                    if self.detectBranches:
                        branches = self.splitFilesIntoBranches(description)
                        for branch in branches.keys():
                            branchPrefix = self.depotPath + branch + "/"

                            parent = ""

                            filesForCommit = branches[branch]

                            if self.verbose:
                                print "branch is %s" % branch

                            self.updatedBranches.add(branch)

                            if branch not in self.createdBranches:
                                self.createdBranches.add(branch)
                                parent = self.knownBranches[branch]
                                if parent == branch:
                                    parent = ""
                                elif self.verbose:
                                    print "parent determined through known branches: %s" % parent

                            # main branch? use master
                            if branch == "main":
                                branch = "master"
                            else:
                                branch = self.projectName + branch

                            if parent == "main":
                                parent = "master"
                            elif len(parent) > 0:
                                parent = self.projectName + parent

                            branch = self.refPrefix + branch
                            if len(parent) > 0:
                                parent = self.refPrefix + parent

                            if self.verbose:
                                print "looking for initial parent for %s; current parent is %s" % (branch, parent)

                            if len(parent) == 0 and branch in self.initialParents:
                                parent = self.initialParents[branch]
                                del self.initialParents[branch]

                            self.commit(description, filesForCommit, branch, branchPrefix, parent)
                    else:
                        files = self.extractFilesFromCommit(description)
                        self.commit(description, files, self.branch, self.depotPath, self.initialParent)
                        self.initialParent = ""
                except IOError:
                    print self.gitError.read()
                    sys.exit(1)

            if not self.silent:
                print ""
                if len(self.updatedBranches) > 0:
                    sys.stdout.write("Updated branches: ")
                    for b in self.updatedBranches:
                        sys.stdout.write("%s " % b)
                    sys.stdout.write("\n")


        self.gitStream.close()
        if importProcess.wait() != 0:
            die("fast-import failed: %s" % self.gitError.read())
        self.gitOutput.close()
        self.gitError.close()

        if createP4HeadRef:
            system("git symbolic-ref %sHEAD %s" % (self.refPrefix, self.branch))

        return True

class P4Rebase(Command):
    def __init__(self):
        Command.__init__(self)
        self.options = [ optparse.make_option("--with-origin", dest="syncWithOrigin", action="store_true") ]
        self.description = "Fetches the latest revision from perforce and rebases the current work (branch) against it"
        self.syncWithOrigin = False

    def run(self, args):
        sync = P4Sync()
        sync.syncWithOrigin = self.syncWithOrigin
        sync.run([])
        print "Rebasing the current branch"
        oldHead = mypopen("git rev-parse HEAD").read()[:-1]
        system("git rebase p4")
        system("git diff-tree --stat --summary -M %s HEAD" % oldHead)
        return True

class P4Clone(P4Sync):
    def __init__(self):
        P4Sync.__init__(self)
        self.description = "Creates a new git repository and imports from Perforce into it"
        self.usage = "usage: %prog [options] //depot/path[@revRange] [directory]"
        self.needsGit = False

    def run(self, args):
        global gitdir

        if len(args) < 1:
            return False
        depotPath = args[0]
        dir = ""
        if len(args) == 2:
            dir = args[1]
        elif len(args) > 2:
            return False

        if not depotPath.startswith("//"):
            return False

        if len(dir) == 0:
            dir = depotPath
            atPos = dir.rfind("@")
            if atPos != -1:
                dir = dir[0:atPos]
            hashPos = dir.rfind("#")
            if hashPos != -1:
                dir = dir[0:hashPos]

            if dir.endswith("..."):
                dir = dir[:-3]

            if dir.endswith("/"):
               dir = dir[:-1]

            slashPos = dir.rfind("/")
            if slashPos != -1:
                dir = dir[slashPos + 1:]

        print "Importing from %s into %s" % (depotPath, dir)
        os.makedirs(dir)
        os.chdir(dir)
        system("git init")
        gitdir = os.getcwd() + "/.git"
        if not P4Sync.run(self, [depotPath]):
            return False
        if self.branch != "master":
            if gitBranchExists("refs/remotes/p4/master"):
                system("git branch master refs/remotes/p4/master")
                system("git checkout -f")
            else:
                print "Could not detect main branch. No checkout/master branch created."
        return True

class HelpFormatter(optparse.IndentedHelpFormatter):
    def __init__(self):
        optparse.IndentedHelpFormatter.__init__(self)

    def format_description(self, description):
        if description:
            return description + "\n"
        else:
            return ""

def printUsage(commands):
    print "usage: %s <command> [options]" % sys.argv[0]
    print ""
    print "valid commands: %s" % ", ".join(commands)
    print ""
    print "Try %s <command> --help for command specific help." % sys.argv[0]
    print ""

commands = {
    "debug" : P4Debug(),
    "submit" : P4Submit(),
    "sync" : P4Sync(),
    "rebase" : P4Rebase(),
    "clone" : P4Clone(),
    "rollback" : P4RollBack()
}

if len(sys.argv[1:]) == 0:
    printUsage(commands.keys())
    sys.exit(2)

cmd = ""
cmdName = sys.argv[1]
try:
    cmd = commands[cmdName]
except KeyError:
    print "unknown command %s" % cmdName
    print ""
    printUsage(commands.keys())
    sys.exit(2)

options = cmd.options
cmd.gitdir = gitdir

args = sys.argv[2:]

if len(options) > 0:
    options.append(optparse.make_option("--git-dir", dest="gitdir"))

    parser = optparse.OptionParser(cmd.usage.replace("%prog", "%prog " + cmdName),
                                   options,
                                   description = cmd.description,
                                   formatter = HelpFormatter())

    (cmd, args) = parser.parse_args(sys.argv[2:], cmd);

if cmd.needsGit:
    gitdir = cmd.gitdir
    if len(gitdir) == 0:
        gitdir = ".git"
        if not isValidGitDir(gitdir):
            gitdir = mypopen("git rev-parse --git-dir").read()[:-1]
            if os.path.exists(gitdir):
                cdup = mypopen("git rev-parse --show-cdup").read()[:-1];
                if len(cdup) > 0:
                    os.chdir(cdup);

    if not isValidGitDir(gitdir):
        if isValidGitDir(gitdir + "/.git"):
            gitdir += "/.git"
        else:
            die("fatal: cannot locate git repository at %s" % gitdir)

    os.environ["GIT_DIR"] = gitdir

if not cmd.run(args):
    parser.print_help()