Add support for generating thunk source from IDL.

ppapi/generators/idl_thunk.py

Index: ppapi/generators/idl_thunk.py
diff --git a/ppapi/generators/idl_thunk.py b/ppapi/generators/idl_thunk.py
new file mode 100755
index 0000000000000000000000000000000000000000..4b31f73826f74ff97e38fdcda0800302b32df84d
--- /dev/null
+++ b/ppapi/generators/idl_thunk.py
@@ -0,0 +1,398 @@
+#!/usr/bin/env python
+# 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.
+
+""" Generator for C++ style thunks """
+
+import glob
+import os
+import re
+import sys
+
+from idl_log import ErrOut, InfoOut, WarnOut
+from idl_node import IDLAttribute, IDLNode
+from idl_ast import IDLAst
+from idl_option import GetOption, Option, ParseOptions
+from idl_outfile import IDLOutFile
+from idl_parser import ParseFiles
+from idl_c_proto import CGen, GetNodeComments, CommentLines, Comment
+from idl_generator import Generator, GeneratorByFile
+
+Option('thunkroot', 'Base directory of output',
+       default=os.path.join('..', 'thunk'))
+
+
+class TGenError(Exception):
+  def __init__(self, msg):
+    self.value = msg
+
+  def __str__(self):
+    return repr(self.value)
+
+
+def _GetBaseName(filenode):
+  """Returns the base name for an interface, given the filename."""

[noelallen1, 2012/11/15 22:03:18]

FYI: Interface name does not always match source file name unfortunately. 
Usually this is a mismatch spacing.  The property 'macro' renames the interface.
 For example:

ppb_graphics_3d.idl generates the macro:
  PPB_GRAPHICS_3D_INTERFACE
However it generates the interface
  struct PPB_Graphics3D

Since you appear to only use this for generating filenames, I think you are
okay, but wanted to make sure you didn't have an invalid assumption here. 

[teravest, 2012/11/16 17:33:36]

I changed the method name to _GetBaseFileName to make this easier to read (and
less error prone if the code is changed in the future).

Thanks.

[dmichael (off chromium), 2012/11/16 18:24:44]

Maybe explain what "base name" means? Just an example would suffice, I think.

[teravest, 2012/11/16 18:52:36]

Examples added.

+  path, name = os.path.split(filenode.GetProperty('NAME'))
+  name = os.path.splitext(name)[0]
+  if name.endswith('_dev'):
+    # Clip off _dev suffix.
+    name = name[:-len('_dev')]
+  return name
+
+
+def _GetHeaderFileName(filenode):
+  """Returns the name for the header for this file."""
+  path, name = os.path.split(filenode.GetProperty('NAME'))
+  name = os.path.splitext(name)[0]
+  if path:
+    header = "ppapi/c/%s/%s.h" % (path, name)
+  else:
+    header = "ppapi/c/%s.h" % name
+  return header
+
+
+def _GetThunkFileName(filenode, relpath):
+  """Returns the thunk file name."""
+  path = os.path.split(filenode.GetProperty('NAME'))[0]
+  name = _GetBaseName(filenode)
+  # We don't reattach the path for thunk.
+  if relpath: name = os.path.join(relpath, name)
+  name = '%s%s' % (name, '_thunk.cc')
+  return name
+
+
+def _MakeEnterLine(filenode, interface, arg, handle_errors, callback):
+  """Returns an EnterInstance/EnterResource string for a function."""
+  if arg[0] == 'PP_Instance':
+    if callback is None:
+      return 'EnterInstance enter(%s);' % arg[1]
+    else:
+      return 'EnterInstance enter(%s, %s);' % (arg[1], callback)
+  elif arg[0] == 'PP_Resource':
+    api_name = interface.GetName()
+    if api_name.endswith('_Dev'):
+      api_name = api_name[:-len('_Dev')]
+    api_name += '_API'
+
+    enter_type = 'EnterResource<%s>' % api_name
+    if callback is None:
+      return '%s enter(%s, %s);' % (enter_type, arg[1],
+                                    str(handle_errors).lower())
+    else:
+      return '%s enter(%s, %s, %s);' % (enter_type, arg[1],
+                                        callback,
+                                        str(handle_errors).lower())
+  else:
+    raise TGenError("Unknown type for _MakeEnterLine: %s" % arg[0])
+
+
+def _GetShortName(interface, filter_suffixes):
+  """Return a shorter interface name that matches Is* and Create* functions."""
+  parts = interface.GetName().split('_')[1:]
+  tail = parts[len(parts) - 1]
+  if tail in filter_suffixes:
+    parts = parts[:-1]
+  return ''.join(parts)
+
+
+def _IsTypeCheck(interface, node):
+  """Returns true if node represents a type-checking function."""
+  return node.GetName() == 'Is%s' % _GetShortName(interface, ['Dev', 'Private'])
+
+
+def _GetCreateFuncName(interface):
+  """Returns the creation function name for an interface."""
+  return 'Create%s' % _GetShortName(interface, ['Dev'])
+
+
+def _GetDefaultFailureValue(t):
+  """Returns the default failure value for a given type.
+
+  Returns None if no default failure value exists for the type.
+  """
+  values = {
+      'PP_Bool': 'PP_FALSE',
+      'PP_Resource': '0',
+      'struct PP_Var': 'PP_MakeUndefined()',
+      'int32_t': 'enter.retval()',
+      'uint16_t': '0',
+      'uint32_t': '0',
+      'uint64_t': '0',
+  }
+  if t in values:
+    return values[t]
+  return None
+
+
+def _MakeCreateMemberBody(interface, member, args):
+  """Returns the body of a Create() function.
+
+  Args:
+    interface - IDLNode for the interface
+    member - IDLNode for member function
+    args - List of arguments for the Create() function
+  """
+  if args[0][0] == 'PP_Resource':
+    body = '  Resource* object =\n'
+    body += '      PpapiGlobals::Get()->GetResourceTracker()->'
+    body += 'GetResource(%s);\n' % args[0][1]
+    body += '  if (!object)\n'
+    body += '    return 0;\n'
+    body += '  EnterResourceCreation enter(object->pp_instance());\n'
+  elif args[0][0] == 'PP_Instance':
+    body = '  EnterResourceCreation enter(%s);\n' % args[0][1]
+  else:
+    raise TGenError('Unknown arg type for Create(): %s' % args[0][0])
+
+  body += '  if (enter.failed())\n'
+  body += '    return 0;\n'
+  arg_list = ', '.join([a[1] for a in args])
+  if member.GetProperty('create_func'):
+    create_func = member.GetProperty('create_func')
+  else:
+    create_func = _GetCreateFuncName(interface)
+  body += '  return enter.functions()->%s(%s);' % (create_func,
+                                                   arg_list)
+  return body
+
+
+def _MakeNormalMemberBody(filenode, node, member, rtype, args):
+  """Returns the body of a typical function.
+
+  Args:
+    filenode - IDLNode for the file
+    node - IDLNode for the interface
+    member - IDLNode for the member function
+    rtype - Return type for the member function
+    args - List of arguments for the member function

[dmichael (off chromium), 2012/11/16 18:24:44]

maybe mention that it's a list of 2-element lists, where the first is the type,
second is the name? Or is that just the convention everywhere in the IDL stuff?

If it's not the convention...  making it a small object with 2 named properties
might make the code more readable...  e.g.,
args[len(args) - 1].type
...seems more obvious than...
args[len(args) - 1][0]

[teravest, 2012/11/16 18:52:36]

It's actually a list of 4 element tuples, which is just what the IDL code uses
to pass everything around.

I agree that a type would be better, but I didn't want to do a lot of
refactoring of the existing IDL code; I can do that if you'd like.

For now, I added a comment.

[noelallen1, 2012/11/16 20:27:28]

I've been meaning to make that change for a while.  It's is lots of places so I
don't think this is the correct CL for it.


On 2012/11/16 18:52:36, Justin TerAvest wrote:

+  """
+  is_callback_func = args[len(args) - 1][0] == 'struct PP_CompletionCallback'
+
+  if is_callback_func:
+    call_args = args[:-1] + [('', 'enter.callback()', '', '')]
+  else:
+    call_args = args
+
+  if args[0][0] == 'PP_Instance':
+    call_arglist = ', '.join(a[1] for a in call_args)
+    function_container = 'functions'
+  else:
+    call_arglist = ', '.join(a[1] for a in call_args[1:])
+    function_container = 'object'
+
+  invocation = 'enter.%s()->%s(%s)' % (function_container,
+                                       member.GetName(),
+                                       call_arglist)
+
+  handle_errors = not (member.GetProperty('report_errors') == 'False')
+  if is_callback_func:
+    body = '  %s\n' % _MakeEnterLine(filenode, node, args[0], handle_errors,
+                                     args[len(args) - 1][1])
+    body += '  if (enter.failed())\n'
+    value = member.GetProperty('on_failure')
+    if value is None:
+      value = 'enter.retval()'
+    body += '    return %s;\n' % value
+    body += '  return enter.SetResult(%s);\n' % invocation
+  elif rtype == 'void':
+    body = '  %s\n' % _MakeEnterLine(filenode, node, args[0], handle_errors,
+                                     None)
+    body += '  if (enter.succeeded())\n'
+    body += '    %s;' % invocation
+  else:
+    value = member.GetProperty('on_failure')
+    if value is None:
+      value = _GetDefaultFailureValue(rtype)
+    if value is None:
+      raise TGenError('No default value for rtype %s' % rtype)
+
+    body = '  %s\n' % _MakeEnterLine(filenode, node, args[0], handle_errors,
+                                     None)
+    body += '  if (enter.failed())\n'
+    body += '    return %s;\n' % value
+    body += '  return %s;' % invocation
+  return body
+
+
+def DefineMember(filenode, node, member, release, include_version):
+  """Returns a definition for a member function of an interface.
+
+  Args:
+    filenode - IDLNode for the file
+    node - IDLNode for the interface
+    member - IDLNode for the member function
+    release - release to generate
+    include_version - include the version in emitted function name.
+  Returns:
+    A string with the member definition.
+  """
+  cgen = CGen()
+  rtype, name, arrays, args = cgen.GetComponents(member, release, 'return')
+
+  if _IsTypeCheck(node, member):
+    body = '  %s\n' % _MakeEnterLine(filenode, node, args[0], False, None)
+    body += '  return PP_FromBool(enter.succeeded());'
+  elif member.GetName() == 'Create':
+    body = _MakeCreateMemberBody(node, member, args)
+  else:
+    body = _MakeNormalMemberBody(filenode, node, member, rtype, args)
+
+  signature = cgen.GetSignature(member, release, 'return', func_as_ptr=False,
+                                include_version=include_version)
+  member_code = '%s {\n%s\n}' % (signature, body)
+  return cgen.Indent(member_code, tabs=0)
+
+
+class TGen(GeneratorByFile):
+  def __init__(self):
+    Generator.__init__(self, 'Thunk', 'tgen', 'Generate the C++ thunk.')
+
+  def GenerateFile(self, filenode, releases, options):
+    savename = _GetThunkFileName(filenode, GetOption('thunkroot'))
+    my_min, my_max = filenode.GetMinMax(releases)
+    if my_min > releases[-1] or my_max < releases[0]:
+      if os.path.isfile(savename):
+        print "Removing stale %s for this range." % filenode.GetName()
+        os.remove(os.path.realpath(savename))
+      return False
+    do_generate = filenode.GetProperty('generate_thunk')
+    if not do_generate:
+      return False
+
+    thunk_out = IDLOutFile(savename)
+    self.GenerateHead(thunk_out, filenode, releases, options)
+    self.GenerateBody(thunk_out, filenode, releases, options)
+    self.GenerateTail(thunk_out, filenode, releases, options)
+    return thunk_out.Close()
+
+  def GenerateHead(self, out, filenode, releases, options):
+    __pychecker__ = 'unusednames=options'
+    cgen = CGen()
+
+    cright_node = filenode.GetChildren()[0]
+    assert(cright_node.IsA('Copyright'))
+    out.Write('%s\n' % cgen.Copyright(cright_node))
+
+    # Wrap the From ... modified ... comment if it would be >80 characters.
+    from_text = 'From %s' % (
+        filenode.GetProperty('NAME').replace(os.sep,'/'))
+    modified_text = 'modified %s.' % (
+        filenode.GetProperty('DATETIME'))
+    if len(from_text) + len(modified_text) < 74:
+      out.Write('/* %s %s */\n\n' % (from_text, modified_text))
+    else:
+      out.Write('/* %s,\n *   %s\n */\n\n' % (from_text, modified_text))
+
+
+    # TODO(teravest): Don't emit includes we don't need.
+    includes = ['ppapi/c/pp_errors.h',
+                'ppapi/shared_impl/tracked_callback.h',
+                'ppapi/thunk/enter.h',
+                'ppapi/thunk/ppb_instance_api.h',
+                'ppapi/thunk/resource_creation_api.h',
+                'ppapi/thunk/thunk.h']
+    includes.append(_GetHeaderFileName(filenode))
+    includes.append('ppapi/thunk/%s_api.h' % _GetBaseName(filenode))
+    for include in sorted(includes):
+      out.Write('#include "%s"\n' % include)
+    out.Write('\n')
+    out.Write('namespace ppapi {\n')
+    out.Write('namespace thunk {\n')
+    out.Write('\n')
+    out.Write('namespace {\n')
+    out.Write('\n')
+
+  def GenerateBody(self, out, filenode, releases, options):
+    __pychecker__ = 'unusednames=options'
+    for node in filenode.GetListOf('Interface'):
+      # Skip if this node is not in this release
+      if not node.InReleases(releases):
+        print "Skipping %s" % node
+        continue
+
+      # Generate Member functions
+      if node.IsA('Interface'):
+        members = []
+        for child in node.GetListOf('Member'):
+          build_list = child.GetUniqueReleases(releases)
+          # We have to filter out releases this node isn't in.
+          build_list = filter(lambda r: child.InReleases([r]), build_list)
+          if len(build_list) == 0:
+            continue
+          release = build_list[-1]  # Pick the newest release.
+          member = DefineMember(filenode, node, child, release, False)
+          if not member:
+            continue
+          members.append(member)
+          for build in build_list[:-1]:
+            member = DefineMember(filenode, node, child, build, True)
+            if not member:
+              continue
+            members.append(member)
+        out.Write('\n\n'.join(members))
+
+  def GenerateTail(self, out, filenode, releases, options):
+    __pychecker__ = 'unusednames=options'
+    cgen = CGen()
+
+    version_list = []
+    out.Write('\n\n')
+    for node in filenode.GetListOf('Interface'):
+      build_list = node.GetUniqueReleases(releases)
+      for build in build_list:
+        version = node.GetVersion(build).replace('.', '_')
+        thunk_name = 'g_' + node.GetName().lower() + '_thunk_' + \
+                      version
+        thunk_type = '_'.join((node.GetName(), version))
+        version_list.append((thunk_type, thunk_name))
+
+        out.Write('const %s %s = {\n' % (thunk_type, thunk_name))
+        for child in node.GetListOf('Member'):
+          rtype, name, arrays, args = cgen.GetComponents(
+              child, build, 'return')
+          if child.InReleases([build]):  # TEST
+            out.Write('  &%s,\n' % name)
+        out.Write('};\n\n')
+
+    out.Write('}  // namespace\n')
+    out.Write('\n')
+    for thunk_type, thunk_name in version_list:
+      thunk_decl = 'const %s* Get%s_Thunk() {\n' % (thunk_type, thunk_type)
+      if len(thunk_decl) > 80:
+        thunk_decl = 'const %s*\n    Get%s_Thunk() {\n' % (thunk_type,
+                                                           thunk_type)
+      out.Write(thunk_decl)
+      out.Write('  return &%s;\n' % thunk_name)
+      out.Write('}\n')
+      out.Write('\n')
+    out.Write('}  // namespace thunk\n')
+    out.Write('}  // namespace ppapi\n')
+
+
+tgen = TGen()
+
+
+def Main(args):
+  # Default invocation will verify the golden files are unchanged.
+  failed = 0
+  if not args:
+    args = ['--wnone', '--diff', '--test', '--thunkroot=.']
+
+  ParseOptions(args)
+
+  idldir = os.path.split(sys.argv[0])[0]
+  idldir = os.path.join(idldir, 'test_thunk', '*.idl')
+  filenames = glob.glob(idldir)
+  ast = ParseFiles(filenames)
+  if tgen.GenerateRange(ast, ['M13', 'M14'], {}):
+    print "Golden file for M13-M14 failed."
+    failed = 1
+  else:
+    print "Golden file for M13-M14 passed."
+
+  return failed
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))