Create js_library and js_binary templates for closure compiling.

third_party/closure_compiler/js_binary.py

Index: third_party/closure_compiler/js_binary.py
diff --git a/third_party/closure_compiler/js_binary.py b/third_party/closure_compiler/js_binary.py
new file mode 100644
index 0000000000000000000000000000000000000000..64fc5e30c45e6d0066928a7895f535a668891f0a
--- /dev/null
+++ b/third_party/closure_compiler/js_binary.py
@@ -0,0 +1,122 @@
+# Copyright 2017 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.
+"""Used by a js_binary action to compile javascript files.
+
+This script takes in a list of sources and dependencies and compiles them all
+together into a single compiled .js file.  The dependencies are ordered in a
+post-order, left-to-right traversal order.  If multiple instances of the same
+source file are read, only the first is kept. The script can also take in
+optional --defs argument which will add custom flags to the comiler.  Any extern
+files can also be passed in using the --extern flag.
+"""
+
+from argparse import ArgumentParser
+import os
+import subprocess
+import sys
+
+EXIT_SUCCESS = 0
+EXIT_FAILURE = 1
+
+def IsExecutable(path):
+  """Returns whether file at |path| exists and is executable."""
+  return os.path.isfile(path) and os.access(path, os.X_OK)
+
+def FindCommand(command):
+  """Looks up for |commmand| in PATH."""
+  filepath, _ = os.path.split(command)
+  if filepath:

[slan, 2017/04/07 23:08:39]

nit: Use "and" here.

[damargulis, 2017/04/08 00:19:49]

Done.

+    if IsExecutable(command):

[mbjorge, 2017/04/07 23:11:19]

should this be IsExecutable(filepath)?

[damargulis, 2017/04/08 00:19:49]

I don't think so.  I borrowed most of this code from
https://cs.corp.google.com/eureka_internal/chromium/src/build/util/java_actio...
with some minor changes.  They have it as IsExecutable(command) there.  I think
the idea is that if filepath exists, then it means that command was passed in as
a full path, and may lead directly to an executable.  filepath would just be the
directory that the executable lives in.

+      return command
+
+  if sys.platform == 'win32':
+    # On Windows, if the command does not have an extension, cmd.exe will
+    # try all extensions from PATHEXT when resolving the full path.
+    command, ext = os.path.splitext(command)
+    if not ext:

[mbjorge, 2017/04/07 23:30:19]

exts = [ext] if ext else os.environ['PATHEXT'].split(os.path.pathsep)

[damargulis, 2017/04/08 00:19:49]

Done.

+      exts = os.environ['PATHEXT'].split(os.path.pathsep)
+    else:
+      exts = [ext]
+  else:
+    exts = ['']
+
+  for path in os.environ['PATH'].split(os.path.pathsep):
+    for ext in exts:
+      path = os.path.join(path, command) + ext
+      if IsExecutable(path):
+        return path
+
+  return None
+
+
+def RunCompiler(args):
+  """Runs the closure compiler with |args|."""
+  java_path = FindCommand('java')
+  if not java_path:
+    sys.stderr.write('java: command not found\n')
+    sys.exit(EXIT_FAILURE)
+  return subprocess.check_call([java_path, '-jar'] + args)
+
+def ParseDepList(dep):
+  """Parses a depenency list, returns |sources, deps|."""
+  with open(dep, 'r') as dep_list:
+    lines = [line.strip() for line in dep_list.readlines()]
+  split = lines.index('deps:')
+  return lines[1:split], lines[split+1:]
+
+def PostOrder(deps, sources):
+  """Parses the dependency tree creating a post-order listing of sources."""
+  for dep in deps:
+    new_sources, new_deps = ParseDepList(dep)
+    sources = PostOrder(new_deps, sources)
+    sources = sources + [source for source in new_sources
+                         if source not in sources]
+  return sources
+
+def main():
+  parser = ArgumentParser()
+  parser.add_argument('-c', '--compiler', required=True,
+                      help='Path to compiler')
+  parser.add_argument('-s', '--sources', nargs='*', default=[],
+                      help='List of js source files')
+  parser.add_argument('-o', '--output', required=True,
+                      help='Compile to output')
+  parser.add_argument('-d', '--deps', nargs='*', default = [],
+                      help='List of js_libarary dependencies')
+  parser.add_argument('-b', '--bootstrap',
+                      help='A file to include before all others')
+  parser.add_argument('-cf', '--config', nargs='*', default = [],
+                      help='A list of files to include after bootstrap and' \
+                      'before all others')
+  parser.add_argument('-df', '--defs', nargs='*', default = [],
+                      help='A list of custom flags to pass to the compiler. ' \
+                      'Do not include leading dashes')
+  parser.add_argument('-e', '--externs', nargs='*', default = [],
+                      help='A list of extern files to pass to the compiler')
+
+  args = parser.parse_args()
+  sources = PostOrder(args.deps, args.sources)
+
+  defs = ['--' + flag for flag in args.defs]
+
+  compiler_args = [
+      args.compiler,
+  ] + defs
+
+  if(args.externs):
+    compiler_args += ['--externs'] + args.externs
+
+  compiler_args += [
+      '--js_output_file',
+      args.output,
+      '--js',
+  ]
+  if(args.bootstrap):
+    compiler_args += [args.bootstrap]
+  compiler_args += args.config
+  compiler_args += sources
+  RunCompiler(compiler_args)
+
+if __name__ == '__main__':
+  sys.exit(main())