[iOS/GN] Replace the last to gyp-mac-tool commands with standalone scripts.

build/config/ios/write_framework_hmap.py

+# Copyright 2016 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.
+
+import os
+import struct
+import sys
+
+def Main(args):
+  if len(args) < 4:
+    print >> sys.stderr, "Usage: %s output.hmap Foo.framework header1.h..." %\
+        (args[0])
+    return 1
+
+  (out, framework, all_headers) = args[1], args[2], args[3:]
+
+  framework_name = os.path.basename(framework).split('.')[0]
+  all_headers = map(os.path.abspath, all_headers)
+  filelist = {}
+  for header in all_headers:
+    filename = os.path.basename(header)
+    filelist[filename] = header
+    filelist[os.path.join(framework_name, filename)] = header
+  WriteHmap(out, filelist)
+  return 0
+
+
+def NextGreaterPowerOf2(x):
+  return 2**(x).bit_length()
+
+
+def WriteHmap(output_name, filelist):
+  """Generates a header map based on |filelist|.
+
+  Per Mark Mentovai:
+    A header map is structured essentially as a hash table, keyed by names used
+    in #includes, and providing pathnames to the actual files.
+
+  The implementation below and the comment above comes from inspecting:
+    http://www.opensource.apple.com/source/distcc/distcc-2503/distcc_dist/include_server/headermap.py?txt
+  while also looking at the implementation in clang in:
+    https://llvm.org/svn/llvm-project/cfe/trunk/lib/Lex/HeaderMap.cpp
+  """
+  magic = 1751998832
+  version = 1
+  _reserved = 0
+  count = len(filelist)
+  capacity = NextGreaterPowerOf2(count)
+  strings_offset = 24 + (12 * capacity)
+  max_value_length = len(max(filelist.items(), key=lambda (k,v):len(v))[1])
+
+  out = open(output_name, 'wb')
+  out.write(struct.pack('<LHHLLLL', magic, version, _reserved, strings_offset,
+                        count, capacity, max_value_length))
+
+  # Create empty hashmap buckets.
+  buckets = [None] * capacity
+  for file, path in filelist.items():
+    key = 0
+    for c in file:
+      key += ord(c.lower()) * 13
+
+    # Fill next empty bucket.
+    while buckets[key & capacity - 1] is not None:
+      key = key + 1
+    buckets[key & capacity - 1] = (file, path)
+
+  next_offset = 1
+  for bucket in buckets:
+    if bucket is None:
+      out.write(struct.pack('<LLL', 0, 0, 0))
+    else:
+      (file, path) = bucket
+      key_offset = next_offset
+      prefix_offset = key_offset + len(file) + 1
+      suffix_offset = prefix_offset + len(os.path.dirname(path) + os.sep) + 1
+      next_offset = suffix_offset + len(os.path.basename(path)) + 1
+      out.write(struct.pack('<LLL', key_offset, prefix_offset, suffix_offset))
+
+  # Pad byte since next offset starts at 1.
+  out.write(struct.pack('<x'))
+
+  for bucket in buckets:
+    if bucket is not None:
+      (file, path) = bucket
+      out.write(struct.pack('<%ds' % len(file), file))
+      out.write(struct.pack('<s', '\0'))
+      base = os.path.dirname(path) + os.sep
+      out.write(struct.pack('<%ds' % len(base), base))
+      out.write(struct.pack('<s', '\0'))
+      path = os.path.basename(path)
+      out.write(struct.pack('<%ds' % len(path), path))
+      out.write(struct.pack('<s', '\0'))
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv))