Merge features of cronet_licenses.py into licenses.py.

tools/licenses.py

Index: tools/licenses.py
diff --git a/tools/licenses.py b/tools/licenses.py
index 0da272cc874aecf95cebedfad98b73a8377b2518..13f24d1f98b55d7ff5ad238541eb4b93ca21e691 100755
--- a/tools/licenses.py
+++ b/tools/licenses.py
@@ -18,8 +18,10 @@ Commands:
 import argparse
 import cgi
 import os
+import shutil
 import subprocess
 import sys
+import tempfile
 
 # TODO(agrieve): Move build_utils.WriteDepFile into a non-android directory.
 _REPOSITORY_ROOT = os.path.dirname(os.path.dirname(__file__))
@@ -482,9 +484,22 @@ def FindThirdPartyDeps(gn_out_dir, gn_target):
     if not gn_out_dir:
         raise RuntimeError("--gn-out-dir is required if --gn-target is used.")
 
-    gn_deps = subprocess.check_output([_GnBinary(), "desc", gn_out_dir,
-                                       gn_target,
-                                       "deps", "--as=buildfile", "--all"])
+    # Generate gn project in temp directory and use it to find dependencies.
+    # Current gn directory cannot be used when we run this script in a gn action
+    # rule, because gn doesn't allow recursive invocations due to potential side
+    # effects.
+    tmp_dir = None
+    try:
+        tmp_dir = tempfile.mkdtemp(dir = gn_out_dir)
+        shutil.copy(os.path.join(gn_out_dir, "args.gn"), tmp_dir)
+        subprocess.check_output([_GnBinary(), "gen", tmp_dir])
+        gn_deps = subprocess.check_output([
+            _GnBinary(), "desc", tmp_dir, gn_target,
+            "deps", "--as=buildfile", "--all"])
+    finally:
+        if tmp_dir and os.path.exists(tmp_dir):
+            shutil.rmtree(tmp_dir)
+
     third_party_deps = set()
     for build_dep in gn_deps.split():
         if ("third_party" in build_dep and
@@ -614,6 +629,53 @@ def GenerateCredits(
     return True
 
 
+def _ReadFile(path):
+    """Reads a file from disk.
+    Args:
+      path: The path of the file to read, relative to the root of the
+      repository.
+    Returns:
+      The contents of the file as a string.
+    """
+    with open(os.path.join(_REPOSITORY_ROOT, path), 'rb') as f:
+        return f.read()
+
+
+def GenerateLicenseFile(output_file, gn_out_dir, gn_target):
+    """Generate a plain-text LICENSE file which can be used when you ship a part
+    of Chromium code (specified by gn_target) as a stand-alone library
+    (e.g., //ios/web_view).
+
+    The LICENSE file contains licenses of both Chromium and third-party
+    libraries which gn_target depends on. """
+
+    third_party_dirs = FindThirdPartyDeps(gn_out_dir, gn_target)
+
+    # Start with Chromium's LICENSE file.
+    content = [_ReadFile('LICENSE')]
+
+    # Add necessary third_party.
+    for directory in sorted(third_party_dirs):
+        metadata = ParseDir(
+            directory, _REPOSITORY_ROOT, require_license_file=True)
+        content.append('-' * 20)
+        content.append(directory.split('/')[-1])
+        content.append('-' * 20)
+        license_file = metadata['License File']
+        if license_file and license_file != NOT_SHIPPED:
+            content.append(_ReadFile(license_file))
+
+    content_text = '\n'.join(content)
+
+    if output_file:
+        with open(output_file, 'w') as output:
+            output.write(content_text)
+    else:
+        print content_text
+
+    return True
+
+
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('--file-template',
@@ -626,7 +688,8 @@ def main():
                         help='GN output directory for scanning dependencies.')
     parser.add_argument('--gn-target',
                         help='GN target to scan for dependencies.')
-    parser.add_argument('command', choices=['help', 'scan', 'credits'])
+    parser.add_argument('command',
+                        choices=['help', 'scan', 'credits', 'license_file'])
     parser.add_argument('output_file', nargs='?')
     build_utils.AddDepfileOption(parser)
     args = parser.parse_args()
@@ -639,6 +702,10 @@ def main():
                                args.output_file, args.target_os,
                                args.gn_out_dir, args.gn_target, args.depfile):
             return 1
+    elif args.command == 'license_file':
+        if not GenerateLicenseFile(
+                args.output_file, args.gn_out_dir, args.gn_target):
+            return 1
     else:
         print __doc__
         return 1