hgext/convert/p4.py

convert: optimize convert of files that are unmodified from p2 in merges

Conversion of a merge starts with p1 and re-adds the files that were changed in
the merge or came unmodified from p2. Files that are unmodified from p1 will
thus not be touched and take no time. Files that are unmodified from p2 would be
retrieved and rehashed. They would end up getting the same hash as in p2 and end
up reusing the filelog entry and look like the p1 case ... but it was slow.

Instead, make getchanges also return 'files that are unmodified from p2' so the
sink can reuse the existing p2 entry instead of calling getfile.

Reuse of filelog entries can make a big difference when files are big and with
long revlong chains so they take time to retrieve and hash, or when using an
expensive custom getfile function (think
http://mercurial.selenic.com/wiki/ConvertExtension#Customization with a code
reformatter).

This in combination with changes to reuse filectx entries in
localrepo._filecommit make 'unchanged from p2' almost as fast as 'unchanged
from p1'.

This is so far only implemented for the combination of hg source and hg sink.

This is a refactoring/optimization. It is covered by existing tests and show no
changes - which is a good thing.

# Perforce source for convert extension.
#
# Copyright 2009, Frank Kingswood <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from mercurial import util
from mercurial.i18n import _

from common import commit, converter_source, checktool, NoRepo
import marshal
import re

def loaditer(f):
    "Yield the dictionary objects generated by p4"
    try:
        while True:
            d = marshal.load(f)
            if not d:
                break
            yield d
    except EOFError:
        pass

class p4_source(converter_source):
    def __init__(self, ui, path, rev=None):
        super(p4_source, self).__init__(ui, path, rev=rev)

        if "/" in path and not path.startswith('//'):
            raise NoRepo(_('%s does not look like a P4 repository') % path)

        checktool('p4', abort=False)

        self.p4changes = {}
        self.heads = {}
        self.changeset = {}
        self.files = {}
        self.tags = {}
        self.lastbranch = {}
        self.parent = {}
        self.encoding = "latin_1"
        self.depotname = {}           # mapping from local name to depot name
        self.re_type = re.compile(
            "([a-z]+)?(text|binary|symlink|apple|resource|unicode|utf\d+)"
            "(\+\w+)?$")
        self.re_keywords = re.compile(
            r"\$(Id|Header|Date|DateTime|Change|File|Revision|Author)"
            r":[^$\n]*\$")
        self.re_keywords_old = re.compile("\$(Id|Header):[^$\n]*\$")

        self._parse(ui, path)

    def _parse_view(self, path):
        "Read changes affecting the path"
        cmd = 'p4 -G changes -s submitted %s' % util.shellquote(path)
        stdout = util.popen(cmd, mode='rb')
        for d in loaditer(stdout):
            c = d.get("change", None)
            if c:
                self.p4changes[c] = True

    def _parse(self, ui, path):
        "Prepare list of P4 filenames and revisions to import"
        ui.status(_('reading p4 views\n'))

        # read client spec or view
        if "/" in path:
            self._parse_view(path)
            if path.startswith("//") and path.endswith("/..."):
                views = {path[:-3]:""}
            else:
                views = {"//": ""}
        else:
            cmd = 'p4 -G client -o %s' % util.shellquote(path)
            clientspec = marshal.load(util.popen(cmd, mode='rb'))

            views = {}
            for client in clientspec:
                if client.startswith("View"):
                    sview, cview = clientspec[client].split()
                    self._parse_view(sview)
                    if sview.endswith("...") and cview.endswith("..."):
                        sview = sview[:-3]
                        cview = cview[:-3]
                    cview = cview[2:]
                    cview = cview[cview.find("/") + 1:]
                    views[sview] = cview

        # list of changes that affect our source files
        self.p4changes = self.p4changes.keys()
        self.p4changes.sort(key=int)

        # list with depot pathnames, longest first
        vieworder = views.keys()
        vieworder.sort(key=len, reverse=True)

        # handle revision limiting
        startrev = self.ui.config('convert', 'p4.startrev', default=0)
        self.p4changes = [x for x in self.p4changes
                          if ((not startrev or int(x) >= int(startrev)) and
                              (not self.rev or int(x) <= int(self.rev)))]

        # now read the full changelists to get the list of file revisions
        ui.status(_('collecting p4 changelists\n'))
        lastid = None
        for change in self.p4changes:
            cmd = "p4 -G describe -s %s" % change
            stdout = util.popen(cmd, mode='rb')
            d = marshal.load(stdout)
            desc = self.recode(d.get("desc", ""))
            shortdesc = desc.split("\n", 1)[0]
            t = '%s %s' % (d["change"], repr(shortdesc)[1:-1])
            ui.status(util.ellipsis(t, 80) + '\n')

            if lastid:
                parents = [lastid]
            else:
                parents = []

            date = (int(d["time"]), 0)     # timezone not set
            c = commit(author=self.recode(d["user"]),
                       date=util.datestr(date, '%Y-%m-%d %H:%M:%S %1%2'),
                       parents=parents, desc=desc, branch='',
                       extra={"p4": change})

            files = []
            i = 0
            while ("depotFile%d" % i) in d and ("rev%d" % i) in d:
                oldname = d["depotFile%d" % i]
                filename = None
                for v in vieworder:
                    if oldname.startswith(v):
                        filename = views[v] + oldname[len(v):]
                        break
                if filename:
                    files.append((filename, d["rev%d" % i]))
                    self.depotname[filename] = oldname
                i += 1
            self.changeset[change] = c
            self.files[change] = files
            lastid = change

        if lastid:
            self.heads = [lastid]

    def getheads(self):
        return self.heads

    def getfile(self, name, rev):
        cmd = 'p4 -G print %s' \
            % util.shellquote("%s#%s" % (self.depotname[name], rev))
        stdout = util.popen(cmd, mode='rb')

        mode = None
        contents = ""
        keywords = None

        for d in loaditer(stdout):
            code = d["code"]
            data = d.get("data")

            if code == "error":
                raise IOError(d["generic"], data)

            elif code == "stat":
                if d.get("action") == "purge":
                    return None, None
                p4type = self.re_type.match(d["type"])
                if p4type:
                    mode = ""
                    flags = (p4type.group(1) or "") + (p4type.group(3) or "")
                    if "x" in flags:
                        mode = "x"
                    if p4type.group(2) == "symlink":
                        mode = "l"
                    if "ko" in flags:
                        keywords = self.re_keywords_old
                    elif "k" in flags:
                        keywords = self.re_keywords

            elif code == "text" or code == "binary":
                contents += data

        if mode is None:
            return None, None

        if keywords:
            contents = keywords.sub("$\\1$", contents)
        if mode == "l" and contents.endswith("\n"):
            contents = contents[:-1]

        return contents, mode

    def getchanges(self, rev, full):
        if full:
            raise util.Abort(_("convert from p4 do not support --full"))
        return self.files[rev], {}, set()

    def getcommit(self, rev):
        return self.changeset[rev]

    def gettags(self):
        return self.tags

    def getchangedfiles(self, rev, i):
        return sorted([x[0] for x in self.files[rev]])