/dom/bindings/Codegen.py

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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.

# Common codegen classes.

import os
import string

from WebIDL import *

AUTOGENERATED_WARNING_COMMENT = \
    "/* THIS FILE IS AUTOGENERATED - DO NOT EDIT */\n\n"
ADDPROPERTY_HOOK_NAME = '_AddProperty'
FINALIZE_HOOK_NAME = '_Finalize'
TRACE_HOOK_NAME = '_Trace'
CONSTRUCT_HOOK_NAME = '_Construct'
HASINSTANCE_HOOK_NAME = '_HasInstance'

def replaceFileIfChanged(filename, newContents):
    """
    Read a copy of the old file, so that we don't touch it if it hasn't changed.
    Returns True if the file was updated, false otherwise.
    """
    oldFileContents = ""
    try:
        oldFile = open(filename, 'rb')
        oldFileContents = ''.join(oldFile.readlines())
        oldFile.close()
    except:
        pass

    if newContents == oldFileContents:
        return False

    f = open(filename, 'wb')
    f.write(newContents)
    f.close()

def toStringBool(arg):
    return str(not not arg).lower()

def toBindingNamespace(arg):
    return re.sub("((_workers)?$)", "Binding\\1", arg);

class CGThing():
    """
    Abstract base class for things that spit out code.
    """
    def __init__(self):
        pass # Nothing for now
    def declare(self):
        """Produce code for a header file."""
        assert(False)  # Override me!
    def define(self):
        """Produce code for a cpp file."""
        assert(False) # Override me!

class CGNativePropertyHooks(CGThing):
    """
    Generate a NativePropertyHooks for a given descriptor
    """
    def __init__(self, descriptor):
        CGThing.__init__(self)
        self.descriptor = descriptor
    def declare(self):
        return "  extern const NativePropertyHooks NativeHooks;\n"
    def define(self):
        parent = self.descriptor.interface.parent
        parentHooks = ("&" + toBindingNamespace(parent.identifier.name) + "::NativeHooks"
                       if parent else 'NULL')
        return """
const NativePropertyHooks NativeHooks = { ResolveProperty, EnumerateProperties, %s };
""" % parentHooks

class CGDOMJSClass(CGThing):
    """
    Generate a DOMJSClass for a given descriptor
    """
    def __init__(self, descriptor):
        CGThing.__init__(self)
        self.descriptor = descriptor
    def declare(self):
        return "  extern DOMJSClass Class;\n"
    def define(self):
        traceHook = TRACE_HOOK_NAME if self.descriptor.customTrace else 'NULL'
        protoList = ['prototypes::id::' + proto for proto in self.descriptor.prototypeChain]
        # Pad out the list to the right length with _ID_Count so we
        # guarantee that all the lists are the same length.  _ID_Count
        # is never the ID of any prototype, so it's safe to use as
        # padding.
        while len(protoList) < self.descriptor.config.maxProtoChainLength:
            protoList.append('prototypes::id::_ID_Count')
        prototypeChainString = ', '.join(protoList)
        return """
DOMJSClass Class = {
  { "%s",
    JSCLASS_IS_DOMJSCLASS | JSCLASS_HAS_RESERVED_SLOTS(1),
    %s, /* addProperty */
    JS_PropertyStub,       /* delProperty */
    JS_PropertyStub,       /* getProperty */
    JS_StrictPropertyStub, /* setProperty */
    JS_EnumerateStub,
    JS_ResolveStub,
    JS_ConvertStub,
    %s, /* finalize */
    NULL,                  /* checkAccess */
    NULL,                  /* call */
    NULL,                  /* construct */
    NULL,                  /* hasInstance */
    %s, /* trace */
    JSCLASS_NO_INTERNAL_MEMBERS
  },
  { %s },
  -1, %s, DOM_OBJECT_SLOT,
  &NativeHooks
};
""" % (self.descriptor.interface.identifier.name,
       ADDPROPERTY_HOOK_NAME if self.descriptor.concrete and not self.descriptor.workers else 'JS_PropertyStub',
       FINALIZE_HOOK_NAME, traceHook, prototypeChainString,
       str(self.descriptor.nativeIsISupports).lower())

class CGPrototypeJSClass(CGThing):
    def __init__(self, descriptor):
        CGThing.__init__(self)
        self.descriptor = descriptor
    def declare(self):
        # We're purely for internal consumption
        return ""
    def define(self):
        return """
static JSClass PrototypeClass = {
  "%s Prototype", 0,
  JS_PropertyStub,       /* addProperty */
  JS_PropertyStub,       /* delProperty */
  JS_PropertyStub,       /* getProperty */
  JS_StrictPropertyStub, /* setProperty */
  JS_EnumerateStub,
  JS_ResolveStub,
  JS_ConvertStub,
  NULL,                  /* finalize */
  NULL,                  /* checkAccess */
  NULL,                  /* call */
  NULL,                  /* construct */
  NULL,                  /* hasInstance */
  NULL,                  /* trace */
  JSCLASS_NO_INTERNAL_MEMBERS
};
""" % (self.descriptor.interface.identifier.name)

class CGInterfaceObjectJSClass(CGThing):
    def __init__(self, descriptor):
        CGThing.__init__(self)
        self.descriptor = descriptor
    def declare(self):
        # We're purely for internal consumption
        return ""
    def define(self):
        if not self.descriptor.hasInstanceInterface:
            return ""
        ctorname = "NULL" if not self.descriptor.interface.ctor() else CONSTRUCT_HOOK_NAME
        hasinstance = HASINSTANCE_HOOK_NAME
        return """
static JSClass InterfaceObjectClass = {
  "Function", 0,
  JS_PropertyStub,       /* addProperty */
  JS_PropertyStub,       /* delProperty */
  JS_PropertyStub,       /* getProperty */
  JS_StrictPropertyStub, /* setProperty */
  JS_EnumerateStub,
  JS_ResolveStub,
  JS_ConvertStub,
  NULL,                  /* finalize */
  NULL,                  /* checkAccess */
  %s, /* call */
  %s, /* construct */
  %s, /* hasInstance */
  NULL,                  /* trace */
  JSCLASS_NO_INTERNAL_MEMBERS
};
""" % (ctorname, ctorname, hasinstance)

class CGList(CGThing):
    """
    Generate code for a list of GCThings.  Just concatenates them together, with
    an optional joiner string.  "\n" is a common joiner.
    """
    def __init__(self, children, joiner=""):
        CGThing.__init__(self)
        self.children = children
        self.joiner = joiner
    def append(self, child):
        self.children.append(child)
    def prepend(self, child):
        self.children.insert(0, child)
    def declare(self):
        return self.joiner.join([child.declare() for child in self.children
                                 if child is not None])
    def define(self):
        return self.joiner.join([child.define() for child in self.children
                                 if child is not None])

class CGGeneric(CGThing):
    """
    A class that spits out a fixed string into the codegen.  Can spit out a
    separate string for the declaration too.
    """
    def __init__(self, define="", declare=""):
        self.declareText = declare
        self.defineText = define
    def declare(self):
        return self.declareText
    def define(self):
        return self.defineText

# We'll want to insert the indent at the beginnings of lines, but we
# don't want to indent empty lines.  So only indent lines that have a
# non-newline character on them.
lineStartDetector = re.compile("^(?=[^\n#])", re.MULTILINE)
class CGIndenter(CGThing):
    """
    A class that takes another CGThing and generates code that indents that
    CGThing by some number of spaces.  The default indent is two spaces.
    """
    def __init__(self, child, indentLevel=2):
        CGThing.__init__(self)
        self.child = child
        self.indent = " " * indentLevel
    def declare(self):
        decl = self.child.declare()
        if decl is not "":
            return re.sub(lineStartDetector, self.indent, decl)
        else:
            return ""
    def define(self):
        defn = self.child.define()
        if defn is not "":
            return re.sub(lineStartDetector, self.indent, defn)
        else:
            return ""

class CGWrapper(CGThing):
    """
    Generic CGThing that wraps other CGThings with pre and post text.
    """
    def __init__(self, child, pre="", post="", declarePre=None,
                 declarePost=None, definePre=None, definePost=None,
                 declareOnly=False, defineOnly=False, reindent=False):
        CGThing.__init__(self)
        self.child = child
        self.declarePre = declarePre or pre
        self.declarePost = declarePost or post
        self.definePre = definePre or pre
        self.definePost = definePost or post
        self.declareOnly = declareOnly
        self.defineOnly = defineOnly
        self.reindent = reindent
    def declare(self):
        if self.defineOnly:
            return ''
        decl = self.child.declare()
        if self.reindent:
            # We don't use lineStartDetector because we don't want to
            # insert whitespace at the beginning of our _first_ line.
            decl = stripTrailingWhitespace(
                decl.replace("\n", "\n" + (" " * len(self.declarePre))))
        return self.declarePre + decl + self.declarePost
    def define(self):
        if self.declareOnly:
            return ''
        defn = self.child.define()
        if self.reindent:
            # We don't use lineStartDetector because we don't want to
            # insert whitespace at the beginning of our _first_ line.
            defn = stripTrailingWhitespace(
                defn.replace("\n", "\n" + (" " * len(self.definePre))))
        return self.definePre + defn + self.definePost

class CGNamespace(CGWrapper):
    def __init__(self, namespace, child, declareOnly=False):
        pre = "namespace %s {\n" % namespace
        post = "} // namespace %s\n" % namespace
        CGWrapper.__init__(self, child, pre=pre, post=post,
                           declareOnly=declareOnly)
    @staticmethod
    def build(namespaces, child, declareOnly=False):
        """
        Static helper method to build multiple wrapped namespaces.
        """
        if not namespaces:
            return child
        return CGNamespace(namespaces[0], CGNamespace.build(namespaces[1:],
                                                            child),
                           declareOnly=declareOnly)

class CGIncludeGuard(CGWrapper):
    """
    Generates include guards for a header.
    """
    def __init__(self, prefix, child):
        """|prefix| is the filename without the extension."""
        define = 'mozilla_dom_%s_h__' % prefix
        CGWrapper.__init__(self, child,
                           declarePre='#ifndef %s\n#define %s\n\n' % (define, define),
                           declarePost='\n#endif // %s\n' % define)

class CGHeaders(CGWrapper):
    """
    Generates the appropriate include statements.
    """
    def __init__(self, descriptors, declareIncludes, defineIncludes, child):
        """
        Builds a set of includes to cover |descriptors|.

        Also includes the files in |declareIncludes| in the header
        file and the files in |defineIncludes| in the .cpp.
        """

        # Determine the filenames for which we need headers.
        interfaceDeps = [d.interface for d in descriptors]
        ancestors = []
        for iface in interfaceDeps:
            while iface.parent:
                ancestors.append(iface.parent)
                iface = iface.parent
        interfaceDeps.extend(ancestors)
        bindingIncludes = set(self.getInterfaceFilename(d) for d in interfaceDeps)

        # Grab all the implementation declaration files we need.
        implementationIncludes = set(d.headerFile for d in descriptors)

        # Now find all the things we'll need as arguments because we
        # need to wrap or unwrap them.
        bindingHeaders = set()
        for d in descriptors:
            members = [m for m in d.interface.members]
            signatures = [s for m in members if m.isMethod() for s in m.signatures()]
            types = []
            for s in signatures:
                assert len(s) == 2
                (returnType, arguments) = s
                types.append(returnType)
                types.extend([a.type for a in arguments])

            attrs = [a for a in members if a.isAttr()]
            types.extend([a.type for a in attrs])

            for t in types:
                if t.unroll().isInterface():
                    if t.unroll().isArrayBuffer():
                        bindingHeaders.add("jsfriendapi.h")
                    else:
                        typeDesc = d.getDescriptor(t.unroll().inner.identifier.name)
                        if typeDesc is not None:
                            implementationIncludes.add(typeDesc.headerFile)
                            bindingHeaders.add(self.getInterfaceFilename(typeDesc.interface))

        # Let the machinery do its thing.
        def _includeString(includes):
            return ''.join(['#include "%s"\n' % i for i in includes]) + '\n'
        CGWrapper.__init__(self, child,
                           declarePre=_includeString(declareIncludes),
                           definePre=_includeString(sorted(set(defineIncludes) |
                                                           bindingIncludes |
                                                           bindingHeaders |
                                                           implementationIncludes)))
    @staticmethod
    def getInterfaceFilename(interface):
        basename = os.path.basename(interface.filename())
        return 'mozilla/dom/' + \
               basename.replace('.webidl', 'Binding.h')

class Argument():
    """
    A class for outputting the type and name of an argument
    """
    def __init__(self, argType, name):
        self.argType = argType
        self.name = name
    def __str__(self):
        return self.argType + ' ' + self.name

class CGAbstractMethod(CGThing):
    """
    An abstract class for generating code for a method.  Subclasses
    should override definition_body to create the actual code.

    descriptor is the descriptor for the interface the method is associated with

    name is the name of the method as a string

    returnType is the IDLType of the return value

    args is a list of Argument objects

    inline should be True to generate an inline method, whose body is
    part of the declaration.

    static should be True to generate a static method, which only has
    a definition.
    """
    def __init__(self, descriptor, name, returnType, args, inline=False, static=False):
        CGThing.__init__(self)
        self.descriptor = descriptor
        self.name = name
        self.returnType = returnType
        self.args = args
        self.inline = inline
        self.static = static
    def _argstring(self):
        return ', '.join([str(a) for a in self.args])
    def _decorators(self):
        decorators = []
        if self.inline:
            decorators.append('inline')
        if self.static:
            decorators.append('static')
        decorators.append(self.returnType)
        return ' '.join(decorators)
    def declare(self):
        if self.inline:
            return self._define()
        return "\n  %s %s(%s);\n" % (self._decorators(), self.name, self._argstring())
    def _define(self):
        return self.definition_prologue() + "\n" + self.definition_body() + self.definition_epilogue()
    def define(self):
        return "" if self.inline else self._define()
    def definition_prologue(self):
        maybeNewline = " " if self.inline else "\n"
        return "\n%s%s%s(%s)\n{" % (self._decorators(), maybeNewline,
                                    self.name, self._argstring())
    def definition_epilogue(self):
        return "\n}\n"
    def definition_body(self):
        assert(False) # Override me!

class CGAbstractStaticMethod(CGAbstractMethod):
    """
    Abstract base class for codegen of implementation-only (no
    declaration) static methods.
    """
    def __init__(self, descriptor, name, returnType, args):
        CGAbstractMethod.__init__(self, descriptor, name, returnType, args,
                                  inline=False, static=True)
    def declare(self):
        # We only have implementation
        return ""

class CGAbstractClassHook(CGAbstractStaticMethod):
    """
    Meant for implementing JSClass hooks, like Finalize or Trace. Does very raw
    'this' unwrapping as it assumes that the unwrapped type is always known.
    """
    def __init__(self, descriptor, name, returnType, args):
        CGAbstractStaticMethod.__init__(self, descriptor, name, returnType,
                                        args)

    def definition_body_prologue(self):
        return """
  MOZ_ASSERT(js::GetObjectJSClass(obj) == Class.ToJSClass());
  %s* self = UnwrapDOMObject<%s>(obj, Class.ToJSClass());
""" % (self.descriptor.nativeType, self.descriptor.nativeType)

    def definition_body(self):
        return self.definition_body_prologue() + self.generate_code()

    def generate_code(self):
        # Override me
        assert(False)

class CGAddPropertyHook(CGAbstractClassHook):
    """
    A hook for addProperty, used to preserve our wrapper from GC.
    """
    def __init__(self, descriptor):
        args = [Argument('JSContext*', 'cx'), Argument('JSObject*', 'obj'),
                Argument('jsid', 'id'), Argument('jsval*', 'vp')]
        CGAbstractClassHook.__init__(self, descriptor, ADDPROPERTY_HOOK_NAME,
                                     'JSBool', args)

    def generate_code(self):
        return """
  JSCompartment* compartment = js::GetObjectCompartment(obj);
  xpc::CompartmentPrivate* priv =
    static_cast<xpc::CompartmentPrivate*>(JS_GetCompartmentPrivate(compartment));
  if (!priv->RegisterDOMExpandoObject(obj)) {
    return false;
  }
  self->SetPreservingWrapper(true);
  return true;"""

class CGClassFinalizeHook(CGAbstractClassHook):
    """
    A hook for finalize, used to release our native object.
    """
    def __init__(self, descriptor):
        args = [Argument('JSFreeOp*', 'fop'), Argument('JSObject*', 'obj')]
        CGAbstractClassHook.__init__(self, descriptor, FINALIZE_HOOK_NAME,
                                     'void', args)

    def generate_code(self):
        if self.descriptor.customFinalize:
            return """  if (self) {
    self->%s(%s);
  }""" % (self.name, self.args[0].name)
        if self.descriptor.workers:
            release = "self->Release();"
        else:
            assert self.descriptor.nativeIsISupports
            release = """
  XPCJSRuntime *rt = nsXPConnect::GetRuntimeInstance();
  if (rt) {
    rt->DeferredRelease(NativeToSupports(self));
  } else {
    NS_RELEASE(self);
  }"""
        return """
  self->ClearWrapper();
  %s""" % (release)

class CGClassTraceHook(CGAbstractClassHook):
    """
    A hook to trace through our native object; used for GC and CC
    """
    def __init__(self, descriptor):
        args = [Argument('JSTracer*', 'trc'), Argument('JSObject*', 'obj')]
        CGAbstractClassHook.__init__(self, descriptor, TRACE_HOOK_NAME, 'void',
                                     args)

    def generate_code(self):
        return """  if (self) {
    self->%s(%s);
  }""" % (self.name, self.args[0].name)

class CGClassConstructHook(CGAbstractStaticMethod):
    """
    JS-visible constructor for our objects
    """
    def __init__(self, descriptor):
        args = [Argument('JSContext*', 'cx'), Argument('unsigned', 'argc'), Argument('JS::Value*', 'vp')]
        CGAbstractStaticMethod.__init__(self, descriptor, CONSTRUCT_HOOK_NAME,
                                        'JSBool', args)
        self._ctor = self.descriptor.interface.ctor()

    def define(self):
        if not self._ctor:
            return ""
        return CGAbstractStaticMethod.define(self)

    def definition_body(self):
        return self.generate_code()

    def generate_code(self):
        preamble = """
  JSObject* obj = JS_GetGlobalForObject(cx, JSVAL_TO_OBJECT(JS_CALLEE(cx, vp)));
"""
        preArgs = ""
        if self.descriptor.workers:
            preArgs = "cx, obj, "
        else:
            preamble += """
  nsISupports* global;
  xpc_qsSelfRef globalRef;
  {
    nsresult rv;
    JS::Value val = OBJECT_TO_JSVAL(obj);
    rv = xpc_qsUnwrapArg<nsISupports>(cx, val, &global, &globalRef.ptr, &val);
    if (NS_FAILED(rv)) {
      return Throw<true>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
    }
  }
"""
            preArgs = "global, "

        name = "_" + self._ctor.identifier.name
        nativeName = "_" + MakeNativeName(self._ctor.identifier.name)
        nativeName = self.descriptor.binaryNames.get(name, nativeName)
        callGenerator = CGMethodCall(preArgs, nativeName, True,
                                     self.descriptor, self._ctor, {})
        return preamble + callGenerator.define();

class CGClassHasInstanceHook(CGAbstractStaticMethod):
    def __init__(self, descriptor):
        args = [Argument('JSContext*', 'cx'), Argument('JSObject*', 'obj'),
                Argument('const jsval*', 'v'), Argument('JSBool*', 'bp')]
        CGAbstractStaticMethod.__init__(self, descriptor, HASINSTANCE_HOOK_NAME,
                                        'JSBool', args)

    def define(self):
        if not self.descriptor.hasInstanceInterface:
            return ""
        return CGAbstractStaticMethod.define(self)

    def definition_body(self):
        return self.generate_code()

    def generate_code(self):
        return """  if (!v->isObject()) {
    *bp = false;
    return true;
  }

  jsval protov;
  if (!JS_GetProperty(cx, obj, "prototype", &protov))
    return false;
  if (!protov.isObject()) {
    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_BAD_PROTOTYPE,
                         "%s");
    return false;
  }
  obj = &protov.toObject();

  JSObject* instance = &v->toObject();
  JSObject* proto = JS_GetPrototype(instance);
  while (proto) {
    if (proto == obj) {
      *bp = true;
      return true;
    }
    proto = JS_GetPrototype(proto);
  }

  nsISupports* native =
    nsContentUtils::XPConnect()->GetNativeOfWrapper(cx, instance);
  nsCOMPtr<%s> qiResult = do_QueryInterface(native);
  *bp = !!qiResult;
  return true;
""" % (self.descriptor.name, self.descriptor.hasInstanceInterface)

def isChromeOnly(m):
    return m.getExtendedAttribute("ChromeOnly")

class PropertyDefiner:
    """
    A common superclass for defining things on prototype objects.

    Subclasses should implement generateArray to generate the actual arrays of
    things we're defining.  They should also set self.chrome to the list of
    things exposed to chrome and self.regular to the list of things exposed to
    web pages.  self.chrome must be a superset of self.regular but also include
    all the ChromeOnly stuff.
    """
    def __init__(self, descriptor, name):
        self.descriptor = descriptor
        self.name = name
    def hasChromeOnly(self):
        return len(self.chrome) > len(self.regular)
    def hasNonChromeOnly(self):
        return len(self.regular) > 0
    def variableName(self, chrome):
        if chrome and self.hasChromeOnly():
            return "sChrome" + self.name
        if self.hasNonChromeOnly():
            return "s" + self.name
        return "NULL"
    def __str__(self):
        str = self.generateArray(self.regular, self.variableName(False))
        if self.hasChromeOnly():
            str += self.generateArray(self.chrome, self.variableName(True))
        return str

# The length of a method is the maximum of the lengths of the
# argument lists of all its overloads.
def methodLength(method):
    signatures = method.signatures()
    return max([len(arguments) for (retType, arguments) in signatures])

class MethodDefiner(PropertyDefiner):
    """
    A class for defining methods on a prototype object.
    """
    def __init__(self, descriptor, name, static):
        PropertyDefiner.__init__(self, descriptor, name)

        methods = [m for m in descriptor.interface.members if
                   m.isMethod() and m.isStatic() == static]
        self.chrome = [{"name": m.identifier.name,
                        "length": methodLength(m),
                        "flags": "JSPROP_ENUMERATE"} for m in methods]
        self.regular = [{"name": m.identifier.name,
                         "length": methodLength(m),
                         "flags": "JSPROP_ENUMERATE"}
                        for m in methods if not isChromeOnly(m)]
        if not descriptor.interface.parent and not static and not descriptor.workers:
            self.chrome.append({"name": 'QueryInterface',
                                "length": 1,
                                "flags": "0"})
            self.regular.append({"name": 'QueryInterface',
                                 "length": 1,
                                 "flags": "0"})

        if static:
            if not descriptor.interface.hasInterfaceObject():
                # static methods go on the interface object
                assert not self.hasChromeOnly() and not self.hasNonChromeOnly()
        else:
            if not descriptor.interface.hasInterfacePrototypeObject():
                # non-static methods go on the interface prototype object
                assert not self.hasChromeOnly() and not self.hasNonChromeOnly()

    @staticmethod
    def generateArray(array, name):
        if len(array) == 0:
            return ""

        funcdecls = ['  JS_FN("%s", %s, %s, %s)' %
                     (m["name"], m["name"], m["length"], m["flags"])
                     for m in array]
        # And add our JS_FS_END
        funcdecls.append('  JS_FS_END')

        return ("static JSFunctionSpec %s[] = {\n" +
                ',\n'.join(funcdecls) + "\n" +
                "};\n\n" +
                "static jsid %s_ids[%i] = { JSID_VOID };\n\n") % (name, name, len(array))

class AttrDefiner(PropertyDefiner):
    def __init__(self, descriptor, name):
        PropertyDefiner.__init__(self, descriptor, name)
        self.name = name
        self.chrome = [m for m in descriptor.interface.members if m.isAttr()]
        self.regular = [m for m in self.chrome if not isChromeOnly(m)]

    @staticmethod
    def generateArray(array, name):
        if len(array) == 0:
            return ""

        def flags(attr):
            flags = "JSPROP_SHARED | JSPROP_ENUMERATE"
            if generateNativeAccessors:
                flags = "JSPROP_NATIVE_ACCESSORS | " + flags
            elif attr.readonly:
                return "JSPROP_READONLY | " + flags
            return flags

        def getter(attr):
            return "get_" + attr.identifier.name

        def setter(attr):
            if attr.readonly:
                return "NULL"
            return "set_" + attr.identifier.name

        attrdecls = ['  { "%s", 0, %s, (JSPropertyOp)%s, (JSStrictPropertyOp)%s }' %
                     (attr.identifier.name, flags(attr), getter(attr),
                      setter(attr)) for attr in array]
        attrdecls.append('  { 0, 0, 0, 0, 0 }')

        return ("static JSPropertySpec %s[] = {\n" +
                ',\n'.join(attrdecls) + "\n" +
                "};\n\n" +
                "static jsid %s_ids[%i] = { JSID_VOID };\n\n") % (name, name, len(array))

class ConstDefiner(PropertyDefiner):
    """
    A class for definining constants on the interface object
    """
    def __init__(self, descriptor, name):
        PropertyDefiner.__init__(self, descriptor, name)
        self.name = name
        self.chrome = [m for m in descriptor.interface.members if m.isConst()]
        self.regular = [m for m in self.chrome if not isChromeOnly(m)]

    @staticmethod
    def generateArray(array, name):
        if len(array) == 0:
            return ""

        constdecls = ['  { "%s", %s }' %
                      (const.identifier.name,
                       convertConstIDLValueToJSVal(const.value))
                      for const in array]
        constdecls.append('  { 0, JSVAL_VOID }')

        return ("static ConstantSpec %s[] = {\n" +
                ',\n'.join(constdecls) + "\n" +
                "};\n\n" +
                "static jsid %s_ids[%i] = { JSID_VOID };\n\n") % (name, name, len(array))

class PropertyArrays():
    def __init__(self, descriptor):
        self.staticMethods = MethodDefiner(descriptor, "StaticMethods", True)
        self.methods = MethodDefiner(descriptor, "Methods", False)
        self.attrs = AttrDefiner(descriptor, "Attributes")
        self.consts = ConstDefiner(descriptor, "Constants")

    @staticmethod
    def arrayNames():
        return [ "staticMethods", "methods", "attrs", "consts" ]

    def hasChromeOnly(self):
        return reduce(lambda b, a: b or getattr(self, a).hasChromeOnly(),
                      self.arrayNames(), False)
    def variableNames(self, chrome):
        names = {}
        for array in self.arrayNames():
            names[array] = getattr(self, array).variableName(chrome)
        return names
    def __str__(self):
        define = ""
        for array in self.arrayNames():
            define += str(getattr(self, array))
        return define

class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
    """
    Generate the CreateInterfaceObjects method for an interface descriptor.

    properties should be a PropertyArrays instance.
    """
    def __init__(self, descriptor, properties):
        args = [Argument('JSContext*', 'aCx'), Argument('JSObject*', 'aGlobal'),
                Argument('JSObject*', 'aReceiver')]
        CGAbstractMethod.__init__(self, descriptor, 'CreateInterfaceObjects', 'JSObject*', args)
        self.properties = properties
    def definition_body(self):
        protoChain = self.descriptor.prototypeChain
        if len(protoChain) == 1:
            getParentProto = "JS_GetObjectPrototype(aCx, aGlobal)"
        else:
            parentProtoName = self.descriptor.prototypeChain[-2]
            getParentProto = ("%s::GetProtoObject(aCx, aGlobal, aReceiver)" %
                              toBindingNamespace(parentProtoName))

        needInterfaceObject = self.descriptor.interface.hasInterfaceObject()
        needInterfacePrototypeObject = self.descriptor.interface.hasInterfacePrototypeObject()

        # if we don't need to create anything, why are we generating this?
        assert needInterfaceObject or needInterfacePrototypeObject

        idsToInit = []
        for var in self.properties.arrayNames():
            props = getattr(self.properties, var)
            if props.hasNonChromeOnly():
                idsToInit.append(props.variableName(False))
            if props.hasChromeOnly() and not self.descriptor.workers:
                idsToInit.append(props.variableName(True))
        if len(idsToInit) > 0:
            initIds = CGList(
                [CGGeneric("!InitIds(aCx, %s, %s_ids)" % (varname, varname)) for
                 varname in idsToInit], ' ||\n')
            if len(idsToInit) > 1:
                initIds = CGWrapper(initIds, pre="(", post=")", reindent=True)
            initIds = CGList(
                [CGGeneric("%s_ids[0] == JSID_VOID &&" % idsToInit[0]), initIds],
                "\n")
            initIds = CGWrapper(initIds, pre="if (", post=") {", reindent=True)
            initIds = CGList(
                [initIds,
                 CGGeneric(("  %s_ids[0] = JSID_VOID;\n"
                            "  return NULL;") % idsToInit[0]),
                 CGGeneric("}")],
                "\n")
        else:
            initIds = None
            
        getParentProto = ("JSObject* parentProto = %s;\n"
                          "if (!parentProto) {\n"
                          "  return NULL;\n"
                          "}") % getParentProto

        needInterfaceObjectClass = (needInterfaceObject and
                                    self.descriptor.hasInstanceInterface)
        needConstructor = (needInterfaceObject and
                           not self.descriptor.hasInstanceInterface)
        if self.descriptor.interface.ctor():
            constructHook = CONSTRUCT_HOOK_NAME
            constructArgs = methodLength(self.descriptor.interface.ctor())
        else:
            constructHook = "ThrowingConstructorWorkers" if self.descriptor.workers else "ThrowingConstructor"
            constructArgs = 0

        call = CGGeneric(("return dom::CreateInterfaceObjects(aCx, aGlobal, aReceiver, parentProto,\n"
                          "                                   %s, %s, %s, %d,\n"
                          "                                   %%(methods)s, %%(attrs)s, %%(consts)s, %%(staticMethods)s,\n"
                          "                                   %s);") % (
            "&PrototypeClass" if needInterfacePrototypeObject else "NULL",
            "&InterfaceObjectClass" if needInterfaceObjectClass else "NULL",
            constructHook if needConstructor else "NULL",
            constructArgs,
            '"' + self.descriptor.interface.identifier.name + '"' if needInterfaceObject else "NULL"))

        if self.properties.hasChromeOnly():
            if self.descriptor.workers:
                accessCheck = "mozilla::dom::workers::GetWorkerPrivateFromContext(aCx)->IsChromeWorker()"
            else:
                accessCheck = "xpc::AccessCheck::isChrome(js::GetObjectCompartment(aGlobal))"
            accessCheck = "if (" + accessCheck + ") {\n"
            chrome = CGWrapper(CGGeneric((CGIndenter(call).define() % self.properties.variableNames(True))),
                               pre=accessCheck, post="\n}")
        else:
            chrome = None

        functionBody = CGList(
            [CGGeneric(getParentProto), initIds, chrome,
             CGGeneric(call.define() % self.properties.variableNames(False))],
            "\n\n")
        return CGIndenter(functionBody).define()

class CGGetPerInterfaceObject(CGAbstractMethod):
    """
    A method for getting a per-interface object (a prototype object or interface
    constructor object).
    """
    def __init__(self, descriptor, name, idPrefix=""):
        args = [Argument('JSContext*', 'aCx'), Argument('JSObject*', 'aGlobal'),
                Argument('JSObject*', 'aReceiver')]
        CGAbstractMethod.__init__(self, descriptor, name,
                                  'JSObject*', args, inline=True)
        self.id = idPrefix + "id::" + self.descriptor.name
    def definition_body(self):
        return """

  /* aGlobal and aReceiver are usually the same, but they can be different
     too. For example a sandbox often has an xray wrapper for a window as the
     prototype of the sandbox's global. In that case aReceiver is the xray
     wrapper and aGlobal is the sandbox's global.
   */

  /* Make sure our global is sane.  Hopefully we can remove this sometime */
  if (!(js::GetObjectClass(aGlobal)->flags & JSCLASS_DOM_GLOBAL)) {
    return NULL;
  }
  /* Check to see whether the interface objects are already installed */
  JSObject** protoOrIfaceArray = GetProtoOrIfaceArray(aGlobal);
  JSObject* cachedObject = protoOrIfaceArray[%s];
  if (!cachedObject) {
    protoOrIfaceArray[%s] = cachedObject = CreateInterfaceObjects(aCx, aGlobal, aReceiver);
  }

  /* cachedObject might _still_ be null, but that's OK */
  return cachedObject;""" % (self.id, self.id)

class CGGetProtoObjectMethod(CGGetPerInterfaceObject):
    """
    A method for getting the interface prototype object.
    """
    def __init__(self, descriptor):
        CGGetPerInterfaceObject.__init__(self, descriptor, "GetProtoObject",
                                         "prototypes::")
    def definition_body(self):
        return """
  /* Get the interface prototype object for this class.  This will create the
     object as needed. */""" + CGGetPerInterfaceObject.definition_body(self)

class CGGetConstructorObjectMethod(CGGetPerInterfaceObject):
    """
    A method for getting the interface constructor object.
    """
    def __init__(self, descriptor):
        CGGetPerInterfaceObject.__init__(self, descriptor, "GetConstructorObject",
                                         "constructors::")
    def definition_body(self):
        return """
  /* Get the interface object for this class.  This will create the object as
     needed. */""" + CGGetPerInterfaceObject.definition_body(self)

def CheckPref(descriptor, globalName, varName, retval, wrapperCache = None):
    """
    Check whether bindings should be enabled for this descriptor.  If not, set
    varName to false and return retval.
    """
    if not descriptor.prefable:
        return ""
    if wrapperCache:
       wrapperCache = "      %s->ClearIsDOMBinding();\n" % (wrapperCache)
    else:
        wrapperCache = ""
    return """
  {
    XPCWrappedNativeScope* scope =
      XPCWrappedNativeScope::FindInJSObjectScope(aCx, %s);
    if (!scope) {
      return %s;
    }

    if (!scope->ExperimentalBindingsEnabled()) {
%s      %s = false;
      return %s;
    }
  }
""" % (globalName, retval, wrapperCache, varName, retval)

class CGDefineDOMInterfaceMethod(CGAbstractMethod):
    """
    A method for resolve hooks to try to lazily define the interface object for
    a given interface.
    """
    def __init__(self, descriptor):
        args = [Argument('JSContext*', 'aCx'), Argument('JSObject*', 'aReceiver'),
                Argument('bool*', 'aEnabled')]
        CGAbstractMethod.__init__(self, descriptor, 'DefineDOMInterface', 'bool', args)

    def declare(self):
        if self.descriptor.workers:
            return ''
        return CGAbstractMethod.declare(self)

    def define(self):
        if self.descriptor.workers:
            return ''
        return CGAbstractMethod.define(self)

    def definition_body(self):
        if self.descriptor.interface.hasInterfacePrototypeObject():
            # We depend on GetProtoObject defining an interface constructor
            # object as needed.
            getter = "GetProtoObject"
        else:
            getter = "GetConstructorObject"

        return ("  JSObject* global = JS_GetGlobalForObject(aCx, aReceiver);\n" +
                CheckPref(self.descriptor, "global", "*aEnabled", "false") + 
                """
  *aEnabled = true;
  return !!%s(aCx, global, aReceiver);""" % (getter))

class CGNativeToSupportsMethod(CGAbstractStaticMethod):
    """
    A method to cast our native to an nsISupports.  We do it by casting up the
    interface chain in hopes of getting to something that singly-inherits from
    nsISupports.
    """
    def __init__(self, descriptor):
        args = [Argument(descriptor.nativeType + '*', 'aNative')]
        CGAbstractStaticMethod.__init__(self, descriptor, 'NativeToSupports', 'nsISupports*', args)

    def definition_body(self):
        cur = CGGeneric("aNative")
        for proto in reversed(self.descriptor.prototypeChain[:-1]):
            d = self.descriptor.getDescriptor(proto)
            cast = "static_cast<%s*>(\n" % d.nativeType;
            cur = CGWrapper(CGIndenter(cur), pre=cast, post=")")
        return CGIndenter(CGWrapper(cur, pre="return ", post=";")).define();

class CGWrapMethod(CGAbstractMethod):
    def __init__(self, descriptor):
        # XXX can we wrap if we don't have an interface prototype object?
        assert descriptor.interface.hasInterfacePrototypeObject()
        args = [Argument('JSContext*', 'aCx'), Argument('JSObject*', 'aScope'),
                Argument(descriptor.nativeType + '*', 'aObject'),
                Argument('bool*', 'aTriedToWrap')]
        CGAbstractMethod.__init__(self, descriptor, 'Wrap', 'JSObject*', args)

    def definition_body(self):
        if self.descriptor.workers:
            return """
  *aTriedToWrap = true;
  return aObject->GetJSObject();"""

        return """
  *aTriedToWrap = true;

  JSObject* parent = WrapNativeParent(aCx, aScope, aObject->GetParentObject());
  if (!parent) {
    return NULL;
  }

  JSAutoEnterCompartment ac;
  if (js::GetGlobalForObjectCrossCompartment(parent) != aScope) {
    if (!ac.enter(aCx, parent)) {
      return NULL;
    }
  }

  JSObject* global = JS_GetGlobalForObject(aCx, parent);
%s
  JSObject* proto = GetProtoObject(aCx, global, global);
  if (!proto) {
    return NULL;
  }

  JSObject* obj = JS_NewObject(aCx, &Class.mBase, proto, parent);
  if (!obj) {
    return NULL;
  }

  js::SetReservedSlot(obj, DOM_OBJECT_SLOT, PRIVATE_TO_JSVAL(aObject));
  NS_ADDREF(aObject);

  aObject->SetWrapper(obj);

  return obj;""" % (CheckPref(self.descriptor, "global", "*aTriedToWrap", "NULL", "aObject"))

builtinNames = {
    IDLType.Tags.bool: 'bool',
    IDLType.Tags.int8: 'int8_t',
    IDLType.Tags.int16: 'int16_t',
    IDLType.Tags.int32: 'int32_t',
    IDLType.Tags.int64: 'int64_t',
    IDLType.Tags.uint8: 'uint8_t',
    IDLType.Tags.uint16: 'uint16_t',
    IDLType.Tags.uint32: 'uint32_t',
    IDLType.Tags.uint64: 'uint64_t',
    IDLType.Tags.float: 'float',
    IDLType.Tags.double: 'double'
}

class CastableObjectUnwrapper():
    """
    A class for unwrapping an object named by the "source" argument
    based on the passed-in descriptor and storing it in a variable
    called by the name in the "target" argument.

    codeOnFailure is the code to run if unwrapping fails.
    """
    def __init__(self, descriptor, source, target, codeOnFailure):
        assert descriptor.castable
        self.substitution = { "type" : descriptor.nativeType,
                              "protoID" : "prototypes::id::" + descriptor.name,
                              "source" : source,
                              "target" : target,
                              "codeOnFailure" : codeOnFailure }

    def __str__(self):
        return string.Template(
"""  {
    nsresult rv = UnwrapObject<${protoID}>(cx, ${source}, &${target});
    if (NS_FAILED(rv)) {
      ${codeOnFailure}
    }
  }""").substitute(self.substitution)

class FailureFatalCastableObjectUnwrapper(CastableObjectUnwrapper):
    """
    As CastableObjectUnwrapper, but defaulting to throwing if unwrapping fails
    """
    def __init__(self, descriptor, source, target):
        CastableObjectUnwrapper.__init__(self, descriptor, source, target,
                                         "return Throw<%s>(cx, rv);" %
                                         toStringBool(not descriptor.workers))

class CallbackObjectUnwrapper:
    """
    A class for unwrapping objects implemented in JS.

    |source| is the JSObject we want to use in native code.
    |target| is an nsCOMPtr of the appropriate type in which we store the result.
    """
    def __init__(self, descriptor, source, target, codeOnFailure=None):
        if codeOnFailure is None:
            codeOnFailure = ("return Throw<%s>(cx, rv);" %
                             toStringBool(not descriptor.workers))
        self.descriptor = descriptor
        self.substitution = { "nativeType" : descriptor.nativeType,
                              "source" : source,
                              "target" : target,
                              "codeOnFailure" :  codeOnFailure }

    def __str__(self):
        if self.descriptor.workers:
            return string.Template("""
    ${target} = ${source};""").substitute(self.substitution)

        return string.Template("""
    nsresult rv;
    XPCCallContext ccx(JS_CALLER, cx);
    if (!ccx.IsValid()) {
      rv = NS_ERROR_XPC_BAD_CONVERT_JS;
      ${codeOnFailure}
    }

    const nsIID& iid = NS_GET_IID(${nativeType});
    nsRefPtr<nsXPCWrappedJS> wrappedJS;
    rv = nsXPCWrappedJS::GetNewOrUsed(ccx, ${source}, iid,
                                      NULL, getter_AddRefs(wrappedJS));
    if (NS_FAILED(rv) || !wrappedJS) {
      ${codeOnFailure}
    }

    ${target} = do_QueryObject(wrappedJS.get());
    if (!${target}) {
      ${codeOnFailure}
    }""").substitute(self.substitution)

def getArgumentConversionTemplate(type, descriptor):
    if type.isSequence() or type.isArray():
        raise TypeError("Can't handle sequence or array arguments yet")

    if descriptor is not None:
        assert(type.isInterface())
        # This is an interface that we implement as a concrete class
        # or an XPCOM interface.
        argIsPointer = type.nullable() or type.unroll().inner.isExternal()
        if argIsPointer:
            nameSuffix = ""
        else:
            nameSuffix = "_ptr"

        # If we're going to QI, we want an nsCOMPtr.  But note that XPConnect
        # unwrapping may or may not QI, and we don't know whether it will.  So
        # we use a raw pointer for the isExternal() case, and if a ref is needed
        # it'll be handled by the xpc_qsSelfRef we put on the stack later.
        if descriptor.castable or type.unroll().inner.isExternal() or descriptor.workers:
            declType = "  ${typeName}*"
        else:
            declType = "  nsCOMPtr<${typeName}>"
        template = declType + " ${name}%s;\n" % nameSuffix

        # We have to be very careful here to put anything that might need to
        # hold references across the C++ call in |template| and not
        # |templateBody|, since things in |templateBody| will go out of scope
        # before the call happens.
        templateBody = "  if (${argVal}.isObject()) {"
        if descriptor.castable:
            templateBody += str(FailureFatalCastableObjectUnwrapper(
                    descriptor,
                    "&${argVal}.toObject()",
                    "${name}"+nameSuffix)).replace("\n", "\n  ") + "\n"
        elif descriptor.interface.isCallback():
            templateBody += str(CallbackObjectUnwrapper(
                    descriptor,
                    "&${argVal}.toObject()",
                    "${name}"+nameSuffix)) + "\n"
        elif descriptor.workers:
            templateBody += """
    ${name}%s = &${argVal}.toObject();
    MOZ_ASSERT(${name}%s);
""" % (nameSuffix, nameSuffix)
        else:
            template += "  xpc_qsSelfRef tmpRef_${name};\n"
            template += "  jsval tmpVal_${name} = ${argVal};\n"
            templateBody += """
    ${typeName}* tmp;
    if (NS_FAILED(xpc_qsUnwrapArg<${typeName}>(cx, ${argVal}, &tmp, &tmpRef_${name}.ptr,
                                               &tmpVal_${name}))) {
      return Throw<%s>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
    }
    MOZ_ASSERT(tmp);
    ${name}%s = tmp;
""" % (toStringBool(not descriptor.workers), nameSuffix)

        if type.nullable():
            templateBody += (
                "  } else if (${argVal}.isNullOrUndefined()) {\n"
                "    ${name}%s = NULL;\n" % nameSuffix)

        templateBody += (
            "  } else {\n"
            "    return Throw<%s>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);\n"
            "  }\n" % toStringBool(not descriptor.workers))

        template += templateBody

        if not argIsPointer:
            template += "  ${typeName} &${name} = *${name}_ptr;\n"
            
        return template

    if type.isArrayBuffer():
        template = (
            "  JSObject* ${name};\n"
            "  if (${argVal}.isObject() && JS_IsArrayBufferObject(&${argVal}.toObject(), cx)) {\n"
            "    ${name} = &${argVal}.toObject();\n"
            "  }")
        if type.nullable():
            template += (
                " else if (${argVal}.isNullOrUndefined()) {\n"
                "    ${name} = NULL;\n"
                "  }")

        template += (
            # XXXbz We don't know whether we're on workers, so play it safe
            " else {\n"
            "    return Throw<false>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);\n"
            "  }")

        return template

    if type.isInterface():
        raise TypeError("Interface type with no descriptor: " + type)

    if type.isString():
        # XXXbz Need to figure out string behavior based on extended args?  Also, how to
        # detect them?

        # For nullable strings that are not otherwise annotated, null
        # and undefined become null strings.
        if type.nullable():
            nullBehavior = "eNull"
            undefinedBehavior = "eNull"
        else:
            nullBehavior = "eStringify"
            undefinedBehavior = "eStringify"

        return (
            "  const xpc_qsDOMString ${name}(cx, ${argVal}, ${argPtr},\n"
            "                             xpc_qsDOMString::%s,\n"
            "                             xpc_qsDOMString::%s);\n"
            "  if (!${name}.IsValid()) {\n"
            "    return false;\n"
            "  }\n" % (nullBehavior, undefinedBehavior))

    if type.isEnum():
        if type.nullable():
            raise TypeError("We don't support nullable enumerated arguments "
                            "yet")
        enum = type.inner.identifier.name
        return (
            "  %(enumtype)s ${name};\n"
            "  {\n"
            "    bool ok;\n"
            "    ${name} = static_cast<%(enumtype)s>(FindEnumStringIndex(cx, ${argVal}, %(values)s, &ok));\n"
            "    if (!ok) {\n"
            "      return false;\n"
            "    }\n"
            "  }" % { "enumtype" : enum,
                      "values" : enum + "Values::strings" })

    if type.isCallback():
        # XXXbz we're going to assume that callback types are always
        # nullable and always have [TreatNonCallableAsNull] for now.
        return (
            "  JSObject* ${name};\n"
            "  if (${argVal}.isObject() && JS_ObjectIsCallable(cx, &${argVal}.toObject())) {\n"
            "    ${name} = &${argVal}.toObject();\n"
            "  } else {\n"
            "    ${name} = NULL;\n"
            "  }\n")

    if type.isAny():
        return "  JS::Value ${name} = ${argVal};\n"

    if not type.isPrimitive():
        raise TypeError("Need conversion for argument type '%s'" % type)

    tag = type.tag()
    replacements = dict()
    if type.nullable():
        replacements["declareArg"] = (
            "  Nullable<${typeName}> ${name};\n"
            "  if (${argVal}.isNullOrUndefined()) {\n"
            "    ${name}.SetNull();\n"
            "  } else"…