#!/usr/bin/env python
# Copyright 2014 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script retrieves the history of all V8 branches and
# their corresponding Chromium revisions.

# Requires a chromium checkout with branch heads:
# gclient sync --with_branch_heads
# gclient fetch

import argparse
import csv
import itertools
import json
import os
import re
import sys

from common_includes import *

CONFIG = {
  "BRANCHNAME": "retrieve-v8-releases",
  "PERSISTFILE_BASENAME": "/tmp/v8-releases-tempfile",
}

# Expression for retrieving the bleeding edge revision from a commit message.
PUSH_MSG_SVN_RE = re.compile(r".* \(based on bleeding_edge revision r(\d+)\)$")
PUSH_MSG_GIT_RE = re.compile(r".* \(based on ([a-fA-F0-9]+)\)$")

# Expression for retrieving the merged patches from a merge commit message
# (old and new format).
MERGE_MESSAGE_RE = re.compile(r"^.*[M|m]erged (.+)(\)| into).*$", re.M)

CHERRY_PICK_TITLE_GIT_RE = re.compile(r"^.* \(cherry\-pick\)\.?$")

# New git message for cherry-picked CLs. One message per line.
MERGE_MESSAGE_GIT_RE = re.compile(r"^Merged ([a-fA-F0-9]+)\.?$")

# Expression for retrieving reverted patches from a commit message (old and
# new format).
ROLLBACK_MESSAGE_RE = re.compile(r"^.*[R|r]ollback of (.+)(\)| in).*$", re.M)

# New git message for reverted CLs. One message per line.
ROLLBACK_MESSAGE_GIT_RE = re.compile(r"^Rollback of ([a-fA-F0-9]+)\.?$")

# Expression for retrieving the code review link.
REVIEW_LINK_RE = re.compile(r"^Review URL: (.+)$", re.M)

# Expression with three versions (historical) for extracting the v8 revision
# from the chromium DEPS file.
DEPS_RE = re.compile(r"""^\s*(?:["']v8_revision["']: ["']"""
                     """|\(Var\("googlecode_url"\) % "v8"\) \+ "\/trunk@"""
                     """|"http\:\/\/v8\.googlecode\.com\/svn\/trunk@)"""
                     """([^"']+)["'].*$""", re.M)

# Expression to pick tag and revision for bleeding edge tags. To be used with
# output of 'svn log'.
BLEEDING_EDGE_TAGS_RE = re.compile(
    r"A \/tags\/([^\s]+) \(from \/branches\/bleeding_edge\:(\d+)\)")


def SortBranches(branches):
  """Sort branches with version number names."""
  return sorted(branches, key=SortingKey, reverse=True)


def FilterDuplicatesAndReverse(cr_releases):
  """Returns the chromium releases in reverse order filtered by v8 revision
  duplicates.

  cr_releases is a list of [cr_rev, v8_hsh] reverse-sorted by cr_rev.
  """
  last = ""
  result = []
  for release in reversed(cr_releases):
    if last == release[1]:
      continue
    last = release[1]
    result.append(release)
  return result


def BuildRevisionRanges(cr_releases):
  """Returns a mapping of v8 revision -> chromium ranges.
  The ranges are comma-separated, each range has the form R1:R2. The newest
  entry is the only one of the form R1, as there is no end range.

  cr_releases is a list of [cr_rev, v8_hsh] reverse-sorted by cr_rev.
  cr_rev either refers to a chromium commit position or a chromium branch
  number.
  """
  range_lists = {}
  cr_releases = FilterDuplicatesAndReverse(cr_releases)

  # Visit pairs of cr releases from oldest to newest.
  for cr_from, cr_to in itertools.izip(
      cr_releases, itertools.islice(cr_releases, 1, None)):

    # Assume the chromium revisions are all different.
    assert cr_from[0] != cr_to[0]

    ran = "%s:%d" % (cr_from[0], int(cr_to[0]) - 1)

    # Collect the ranges in lists per revision.
    range_lists.setdefault(cr_from[1], []).append(ran)

  # Add the newest revision.
  if cr_releases:
    range_lists.setdefault(cr_releases[-1][1], []).append(cr_releases[-1][0])

  # Stringify and comma-separate the range lists.
  return dict((hsh, ", ".join(ran)) for hsh, ran in range_lists.iteritems())


def MatchSafe(match):
  if match:
    return match.group(1)
  else:
    return ""


class Preparation(Step):
  MESSAGE = "Preparation."

  def RunStep(self):
    self.CommonPrepare()
    self.PrepareBranch()


class RetrieveV8Releases(Step):
  MESSAGE = "Retrieve all V8 releases."

  def ExceedsMax(self, releases):
    return (self._options.max_releases > 0
            and len(releases) > self._options.max_releases)

  def GetMasterHashFromPush(self, title):
    return MatchSafe(PUSH_MSG_GIT_RE.match(title))

  def GetMergedPatches(self, body):
    patches = MatchSafe(MERGE_MESSAGE_RE.search(body))
    if not patches:
      patches = MatchSafe(ROLLBACK_MESSAGE_RE.search(body))
      if patches:
        # Indicate reverted patches with a "-".
        patches = "-%s" % patches
    return patches

  def GetMergedPatchesGit(self, body):
    patches = []
    for line in body.splitlines():
      patch = MatchSafe(MERGE_MESSAGE_GIT_RE.match(line))
      if patch:
        patches.append(patch)
      patch = MatchSafe(ROLLBACK_MESSAGE_GIT_RE.match(line))
      if patch:
        patches.append("-%s" % patch)
    return ", ".join(patches)


  def GetReleaseDict(
      self, git_hash, master_position, master_hash, branch, version,
      patches, cl_body):
    revision = self.GetCommitPositionNumber(git_hash)
    return {
      # The cr commit position number on the branch.
      "revision": revision,
      # The git revision on the branch.
      "revision_git": git_hash,
      # The cr commit position number on master.
      "master_position": master_position,
      # The same for git.
      "master_hash": master_hash,
      # The branch name.
      "branch": branch,
      # The version for displaying in the form 3.26.3 or 3.26.3.12.
      "version": version,
      # The date of the commit.
      "date": self.GitLog(n=1, format="%ci", git_hash=git_hash),
      # Merged patches if available in the form 'r1234, r2345'.
      "patches_merged": patches,
      # Default for easier output formatting.
      "chromium_revision": "",
      # Default for easier output formatting.
      "chromium_branch": "",
      # Link to the CL on code review. Candiates pushes are not uploaded,
      # so this field will be populated below with the recent roll CL link.
      "review_link": MatchSafe(REVIEW_LINK_RE.search(cl_body)),
      # Link to the commit message on google code.
      "revision_link": ("https://code.google.com/p/v8/source/detail?r=%s"
                        % revision),
    }

  def GetRelease(self, git_hash, branch):
    self.ReadAndPersistVersion()
    base_version = [self["major"], self["minor"], self["build"]]
    version = ".".join(base_version)
    body = self.GitLog(n=1, format="%B", git_hash=git_hash)

    patches = ""
    if self["patch"] != "0":
      version += ".%s" % self["patch"]
      if CHERRY_PICK_TITLE_GIT_RE.match(body.splitlines()[0]):
        patches = self.GetMergedPatchesGit(body)
      else:
        patches = self.GetMergedPatches(body)

    if SortingKey("4.2.69") <= SortingKey(version):
      master_hash = self.GetLatestReleaseBase(version=version)
    else:
      # Legacy: Before version 4.2.69, the master revision was determined
      # by commit message.
      title = self.GitLog(n=1, format="%s", git_hash=git_hash)
      master_hash = self.GetMasterHashFromPush(title)
    master_position = ""
    if master_hash:
      master_position = self.GetCommitPositionNumber(master_hash)
    return self.GetReleaseDict(
        git_hash, master_position, master_hash, branch, version,
        patches, body), self["patch"]

  def GetReleasesFromBranch(self, branch):
    self.GitReset(self.vc.RemoteBranch(branch))
    if branch == self.vc.MasterBranch():
      return self.GetReleasesFromMaster()

    releases = []
    try:
      for git_hash in self.GitLog(format="%H").splitlines():
        if VERSION_FILE not in self.GitChangedFiles(git_hash):
          continue
        if self.ExceedsMax(releases):
          break  # pragma: no cover
        if not self.GitCheckoutFileSafe(VERSION_FILE, git_hash):
          break  # pragma: no cover

        release, patch_level = self.GetRelease(git_hash, branch)
        releases.append(release)

        # Follow branches only until their creation point.
        # TODO(machenbach): This omits patches if the version file wasn't
        # manipulated correctly. Find a better way to detect the point where
        # the parent of the branch head leads to the trunk branch.
        if branch != self.vc.CandidateBranch() and patch_level == "0":
          break

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Clean up checked-out version file.
    self.GitCheckoutFileSafe(VERSION_FILE, "HEAD")
    return releases

  def GetReleaseFromRevision(self, revision):
    releases = []
    try:
      if (VERSION_FILE not in self.GitChangedFiles(revision) or
          not self.GitCheckoutFileSafe(VERSION_FILE, revision)):
        print "Skipping revision %s" % revision
        return []  # pragma: no cover

      branches = map(
          str.strip,
          self.Git("branch -r --contains %s" % revision).strip().splitlines(),
      )
      branch = ""
      for b in branches:
        if b.startswith("origin/"):
          branch = b.split("origin/")[1]
          break
        if b.startswith("branch-heads/"):
          branch = b.split("branch-heads/")[1]
          break
      else:
        print "Could not determine branch for %s" % revision

      release, _ = self.GetRelease(revision, branch)
      releases.append(release)

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Clean up checked-out version file.
    self.GitCheckoutFileSafe(VERSION_FILE, "HEAD")
    return releases


  def RunStep(self):
    self.GitCreateBranch(self._config["BRANCHNAME"])
    releases = []
    if self._options.branch == 'recent':
      # List every release from the last 7 days.
      revisions = self.GetRecentReleases(max_age=7 * DAY_IN_SECONDS)
      for revision in revisions:
        releases += self.GetReleaseFromRevision(revision)
    elif self._options.branch == 'all':  # pragma: no cover
      # Retrieve the full release history.
      for branch in self.vc.GetBranches():
        releases += self.GetReleasesFromBranch(branch)
      releases += self.GetReleasesFromBranch(self.vc.CandidateBranch())
      releases += self.GetReleasesFromBranch(self.vc.MasterBranch())
    else:  # pragma: no cover
      # Retrieve history for a specified branch.
      assert self._options.branch in (self.vc.GetBranches() +
          [self.vc.CandidateBranch(), self.vc.MasterBranch()])
      releases += self.GetReleasesFromBranch(self._options.branch)

    self["releases"] = sorted(releases,
                              key=lambda r: SortingKey(r["version"]),
                              reverse=True)


class UpdateChromiumCheckout(Step):
  MESSAGE = "Update the chromium checkout."

  def RunStep(self):
    cwd = self._options.chromium
    self.GitFetchOrigin("+refs/heads/*:refs/remotes/origin/*",
                        "+refs/branch-heads/*:refs/remotes/branch-heads/*",
                        cwd=cwd)
    # Update v8 checkout in chromium.
    self.GitFetchOrigin(cwd=os.path.join(cwd, "v8"))


def ConvertToCommitNumber(step, revision):
  # Simple check for git hashes.
  if revision.isdigit() and len(revision) < 8:
    return revision
  return step.GetCommitPositionNumber(
      revision, cwd=os.path.join(step._options.chromium, "v8"))


class RetrieveChromiumV8Releases(Step):
  MESSAGE = "Retrieve V8 releases from Chromium DEPS."

  def RunStep(self):
    cwd = self._options.chromium

    # All v8 revisions we are interested in.
    releases_dict = dict((r["revision_git"], r) for r in self["releases"])

    cr_releases = []
    count_past_last_v8 = 0
    try:
      for git_hash in self.GitLog(
          format="%H", grep="V8", branch="origin/master",
          path="DEPS", cwd=cwd).splitlines():
        deps = self.GitShowFile(git_hash, "DEPS", cwd=cwd)
        match = DEPS_RE.search(deps)
        if match:
          cr_rev = self.GetCommitPositionNumber(git_hash, cwd=cwd)
          if cr_rev:
            v8_hsh = match.group(1)
            cr_releases.append([cr_rev, v8_hsh])

          if count_past_last_v8:
            count_past_last_v8 += 1  # pragma: no cover

          if count_past_last_v8 > 20:
            break  # pragma: no cover

          # Stop as soon as we find a v8 revision that we didn't fetch in the
          # v8-revision-retrieval part above (i.e. a revision that's too old).
          # Just iterate a few more times in case there were reverts.
          if v8_hsh not in releases_dict:
            count_past_last_v8 += 1  # pragma: no cover

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Add the chromium ranges to the v8 candidates and master releases.
    all_ranges = BuildRevisionRanges(cr_releases)

    for hsh, ranges in all_ranges.iteritems():
      releases_dict.get(hsh, {})["chromium_revision"] = ranges


# TODO(machenbach): Unify common code with method above.
class RietrieveChromiumBranches(Step):
  MESSAGE = "Retrieve Chromium branch information."

  def RunStep(self):
    cwd = self._options.chromium

    # All v8 revisions we are interested in.
    releases_dict = dict((r["revision_git"], r) for r in self["releases"])

    # Filter out irrelevant branches.
    branches = filter(lambda r: re.match(r"branch-heads/\d+", r),
                      self.GitRemotes(cwd=cwd))

    # Transform into pure branch numbers.
    branches = map(lambda r: int(re.match(r"branch-heads/(\d+)", r).group(1)),
                   branches)

    branches = sorted(branches, reverse=True)

    cr_branches = []
    count_past_last_v8 = 0
    try:
      for branch in branches:
        deps = self.GitShowFile(
            "refs/branch-heads/%d" % branch, "DEPS", cwd=cwd)
        match = DEPS_RE.search(deps)
        if match:
          v8_hsh = match.group(1)
          cr_branches.append([str(branch), v8_hsh])

          if count_past_last_v8:
            count_past_last_v8 += 1  # pragma: no cover

          if count_past_last_v8 > 20:
            break  # pragma: no cover

          # Stop as soon as we find a v8 revision that we didn't fetch in the
          # v8-revision-retrieval part above (i.e. a revision that's too old).
          # Just iterate a few more times in case there were reverts.
          if v8_hsh not in releases_dict:
            count_past_last_v8 += 1  # pragma: no cover

    # Allow Ctrl-C interrupt.
    except (KeyboardInterrupt, SystemExit):  # pragma: no cover
      pass

    # Add the chromium branches to the v8 candidate releases.
    all_ranges = BuildRevisionRanges(cr_branches)
    for revision, ranges in all_ranges.iteritems():
      releases_dict.get(revision, {})["chromium_branch"] = ranges


class CleanUp(Step):
  MESSAGE = "Clean up."

  def RunStep(self):
    self.CommonCleanup()


class WriteOutput(Step):
  MESSAGE = "Print output."

  def Run(self):
    if self._options.csv:
      with open(self._options.csv, "w") as f:
        writer = csv.DictWriter(f,
                                ["version", "branch", "revision",
                                 "chromium_revision", "patches_merged"],
                                restval="",
                                extrasaction="ignore")
        for release in self["releases"]:
          writer.writerow(release)
    if self._options.json:
      with open(self._options.json, "w") as f:
        f.write(json.dumps(self["releases"]))
    if not self._options.csv and not self._options.json:
      print self["releases"]  # pragma: no cover


class Releases(ScriptsBase):
  def _PrepareOptions(self, parser):
    parser.add_argument("-b", "--branch", default="recent",
                        help=("The branch to analyze. If 'all' is specified, "
                              "analyze all branches. If 'recent' (default) "
                              "is specified, track beta, stable and "
                              "candidates."))
    parser.add_argument("-c", "--chromium",
                        help=("The path to your Chromium src/ "
                              "directory to automate the V8 roll."))
    parser.add_argument("--csv", help="Path to a CSV file for export.")
    parser.add_argument("-m", "--max-releases", type=int, default=0,
                        help="The maximum number of releases to track.")
    parser.add_argument("--json", help="Path to a JSON file for export.")

  def _ProcessOptions(self, options):  # pragma: no cover
    options.force_readline_defaults = True
    return True

  def _Config(self):
    return {
      "BRANCHNAME": "retrieve-v8-releases",
      "PERSISTFILE_BASENAME": "/tmp/v8-releases-tempfile",
    }

  def _Steps(self):
    return [
      Preparation,
      RetrieveV8Releases,
      UpdateChromiumCheckout,
      RetrieveChromiumV8Releases,
      RietrieveChromiumBranches,
      CleanUp,
      WriteOutput,
    ]


if __name__ == "__main__":  # pragma: no cover
  sys.exit(Releases().Run())
