# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Utility functions for Windows builds.

This file is copied to the build directory as part of toolchain setup and
is used to set up calls to tools used by the build that need wrappers.
"""

import os
import re
import shutil
import subprocess
import stat
import string
import sys

BASE_DIR = os.path.dirname(os.path.abspath(__file__))

# A regex matching an argument corresponding to the output filename passed to
# link.exe.
_LINK_EXE_OUT_ARG = re.compile('/OUT:(?P<out>.+)$', re.IGNORECASE)
_LINK_PDB_OUT_ARG = re.compile('/PDB:(?P<out>.+)$', re.IGNORECASE)
_LINK_ERROR = re.compile('.* error LNK(\d+):')

# Retry links when this error is hit, to try to deal with crbug.com/782660
_LINKER_RETRY_ERRORS = 1201
# Maximum number of linker retries.
_LINKER_RETRIES = 3

def main(args):
  exit_code = WinTool().Dispatch(args)
  if exit_code is not None:
    sys.exit(exit_code)


class WinTool(object):
  """This class performs all the Windows tooling steps. The methods can either
  be executed directly, or dispatched from an argument list."""

  def _UseSeparateMspdbsrv(self, env, args):
    """Allows to use a unique instance of mspdbsrv.exe per linker instead of a
    shared one."""
    if len(args) < 1:
      raise Exception("Not enough arguments")

    if args[0] != 'link.exe':
      return

    # Use the output filename passed to the linker to generate an endpoint name
    # for mspdbsrv.exe.
    endpoint_name = None
    for arg in args:
      m = _LINK_EXE_OUT_ARG.match(arg)
      if m:
        endpoint_name = re.sub(r'\W+', '',
            '%s_%d' % (m.group('out'), os.getpid()))
        break

    if endpoint_name is None:
      return

    # Adds the appropriate environment variable. This will be read by link.exe
    # to know which instance of mspdbsrv.exe it should connect to (if it's
    # not set then the default endpoint is used).
    env['_MSPDBSRV_ENDPOINT_'] = endpoint_name

  def Dispatch(self, args):
    """Dispatches a string command to a method."""
    if len(args) < 1:
      raise Exception("Not enough arguments")

    method = "Exec%s" % self._CommandifyName(args[0])
    return getattr(self, method)(*args[1:])

  def _CommandifyName(self, name_string):
    """Transforms a tool name like recursive-mirror to RecursiveMirror."""
    return name_string.title().replace('-', '')

  def _GetEnv(self, arch):
    """Gets the saved environment from a file for a given architecture."""
    # The environment is saved as an "environment block" (see CreateProcess
    # and msvs_emulation for details). We convert to a dict here.
    # Drop last 2 NULs, one for list terminator, one for trailing vs. separator.
    pairs = open(arch).read()[:-2].split('\0')
    kvs = [item.split('=', 1) for item in pairs]
    return dict(kvs)

  def ExecStamp(self, path):
    """Simple stamp command."""
    open(path, 'w').close()

  def ExecDeleteFile(self, path):
    """Simple file delete command."""
    if os.path.exists(path):
      os.unlink(path)

  def ExecRecursiveMirror(self, source, dest):
    """Emulation of rm -rf out && cp -af in out."""
    if os.path.exists(dest):
      if os.path.isdir(dest):
        def _on_error(fn, path, dummy_excinfo):
          # The operation failed, possibly because the file is set to
          # read-only. If that's why, make it writable and try the op again.
          if not os.access(path, os.W_OK):
            os.chmod(path, stat.S_IWRITE)
          fn(path)
        shutil.rmtree(dest, onerror=_on_error)
      else:
        if not os.access(dest, os.W_OK):
          # Attempt to make the file writable before deleting it.
          os.chmod(dest, stat.S_IWRITE)
        os.unlink(dest)

    if os.path.isdir(source):
      shutil.copytree(source, dest)
    else:
      shutil.copy2(source, dest)
      # Try to diagnose crbug.com/741603
      if not os.path.exists(dest):
        raise Exception("Copying of %s to %s failed" % (source, dest))

  def ExecLinkWrapper(self, arch, use_separate_mspdbsrv, *args):
    """Filter diagnostic output from link that looks like:
    '   Creating library ui.dll.lib and object ui.dll.exp'
    This happens when there are exports from the dll or exe.
    """
    env = self._GetEnv(arch)
    if use_separate_mspdbsrv == 'True':
      self._UseSeparateMspdbsrv(env, args)
    if sys.platform == 'win32':
      args = list(args)  # *args is a tuple by default, which is read-only.
      args[0] = args[0].replace('/', '\\')
    # https://docs.python.org/2/library/subprocess.html:
    # "On Unix with shell=True [...] if args is a sequence, the first item
    # specifies the command string, and any additional items will be treated as
    # additional arguments to the shell itself.  That is to say, Popen does the
    # equivalent of:
    #   Popen(['/bin/sh', '-c', args[0], args[1], ...])"
    # For that reason, since going through the shell doesn't seem necessary on
    # non-Windows don't do that there.
    pdb_name = None
    for arg in args:
      m = _LINK_PDB_OUT_ARG.match(arg)
      if m:
        pdb_name = m.group('out')
    for retry_count in range(_LINKER_RETRIES):
      retry = False
      link = subprocess.Popen(args, shell=sys.platform == 'win32', env=env,
                              stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
      # Read output one line at a time as it shows up to avoid OOM failures when
      # GBs of output is produced.
      for line in link.stdout:
        if (not line.startswith('   Creating library ') and
            not line.startswith('Generating code') and
            not line.startswith('Finished generating code')):
          m = _LINK_ERROR.match(line)
          if m:
            error_code = int(m.groups()[0])
            if error_code == _LINKER_RETRY_ERRORS:
              print 'Retrying link due to error %d' % error_code
              if pdb_name:
                shutil.copyfile(pdb_name, pdb_name + 'failure_backup')
              retry = True
          print line,
      result = link.wait()
      if not retry:
        break
    return result

  def ExecAsmWrapper(self, arch, *args):
    """Filter logo banner from invocations of asm.exe."""
    env = self._GetEnv(arch)
    popen = subprocess.Popen(args, shell=True, env=env,
                             stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    out, _ = popen.communicate()
    for line in out.splitlines():
      # Split to avoid triggering license checks:
      if (not line.startswith('Copy' + 'right (C' +
                              ') Microsoft Corporation') and
          not line.startswith('Microsoft (R) Macro Assembler') and
          not line.startswith(' Assembling: ') and
          line):
        print line
    return popen.returncode

  def ExecRcWrapper(self, arch, *args):
    """Converts .rc files to .res files."""
    env = self._GetEnv(arch)

    # We run two resource compilers:
    # 1. A custom one at build/toolchain/win/rc/rc.py which can run on
    #    non-Windows, and which has /showIncludes support so we can track
    #    dependencies (e.g. on .ico files) of .rc files.
    # 2. On Windows, regular Microsoft rc.exe, to make sure rc.py produces
    #    bitwise identical output.

    # 1. Run our rc.py.
    # Also pass /showIncludes to track dependencies of .rc files.
    args = list(args)
    rcpy_args = args[:]
    rcpy_args[0:1] = [sys.executable, os.path.join(BASE_DIR, 'rc', 'rc.py')]
    rcpy_res_output = rcpy_args[-2]
    assert rcpy_res_output.startswith('/fo')
    assert rcpy_res_output.endswith('.res')
    rc_res_output = rcpy_res_output + '_ms_rc'
    args[-2] = rc_res_output
    rcpy_args.append('/showIncludes')
    rc_exe_exit_code = subprocess.call(rcpy_args, env=env)
    if rc_exe_exit_code == 0:
      # Since tool("rc") can't have deps, add deps on this script and on rc.py
      # and its deps here, so that rc edges become dirty if rc.py changes.
      print 'Note: including file: ../../build/toolchain/win/tool_wrapper.py'
      print 'Note: including file: ../../build/toolchain/win/rc/rc.py'
      print 'Note: including file: ../../build/toolchain/win/rc/linux64/rc.sha1'
      print 'Note: including file: ../../build/toolchain/win/rc/mac/rc.sha1'
      print 'Note: including file: ../../build/toolchain/win/rc/win/rc.exe.sha1'

    # 2. Run Microsoft rc.exe.
    if sys.platform == 'win32' and rc_exe_exit_code == 0:
      popen = subprocess.Popen(args, shell=True, env=env,
                               stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
      out, _ = popen.communicate()
      # Filter logo banner from invocations of rc.exe. Older versions of RC
      # don't support the /nologo flag.
      for line in out.splitlines():
        if (not line.startswith('Microsoft (R) Windows (R) Resource Compiler')
            and not line.startswith('Copy' + 'right (C' +
                                ') Microsoft Corporation')
            and line):
          print line
      rc_exe_exit_code = popen.returncode
      # Assert Microsoft rc.exe and rc.py produced identical .res files.
      if rc_exe_exit_code == 0:
        import filecmp
        # Strip "/fo" prefix.
        assert filecmp.cmp(rc_res_output[3:], rcpy_res_output[3:])
    return rc_exe_exit_code

  def ExecActionWrapper(self, arch, rspfile, *dirname):
    """Runs an action command line from a response file using the environment
    for |arch|. If |dirname| is supplied, use that as the working directory."""
    env = self._GetEnv(arch)
    # TODO(scottmg): This is a temporary hack to get some specific variables
    # through to actions that are set after GN-time. http://crbug.com/333738.
    for k, v in os.environ.iteritems():
      if k not in env:
        env[k] = v
    args = open(rspfile).read()
    dirname = dirname[0] if dirname else None
    return subprocess.call(args, shell=True, env=env, cwd=dirname)


if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))