wrappers/trace.py

##########################################################################
#
# Copyright 2008-2010 VMware, Inc.
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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"""Common trace code generation."""


# Adjust path
import os.path
import sys
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))

import itertools

import specs.stdapi as stdapi


def getWrapperInterfaceName(interface):
    return "Wrap" + interface.expr


debug = False


class ComplexValueSerializer(stdapi.OnceVisitor):
    '''Type visitors which generates serialization functions for
    complex types.
    
    Simple types are serialized inline.
    '''

    def __init__(self, serializer):
        stdapi.OnceVisitor.__init__(self)
        self.serializer = serializer

    def visitVoid(self, literal):
        pass

    def visitLiteral(self, literal):
        pass

    def visitString(self, string):
        pass

    def visitConst(self, const):
        self.visit(const.type)

    def visitStruct(self, struct):
        # Write array with structure's member names
        numMembers = len(struct.members)
        if numMembers:
            # Ensure member array has nonzero length to avoid MSVC error C2466
            memberNames = '_struct%s_members' % (struct.tag,)
            print('static const char * %s[%u] = {' % (memberNames, numMembers))
            for type, name,  in struct.members:
                if name is None:
                    print('    "",')
                else:
                    print('    "%s",' % (name,))
            print('};')
        else:
            sys.stderr.write('warning: %s has no members\n' % struct.name)
            memberNames = 'nullptr'

        # Write structure's signature
        print('static const trace::StructSig _struct%s_sig = {' % (struct.tag,))
        if struct.name is None:
            structName = '""'
        else:
            structName = '"%s"' % struct.name
        print('    %u, %s, %u, %s' % (struct.id, structName, numMembers, memberNames))
        print('};')
        print()

    def visitArray(self, array):
        self.visit(array.type)

    def visitAttribArray(self, array):
        pass

    def visitBlob(self, array):
        pass

    def visitEnum(self, enum):
        print('static const trace::EnumValue _enum%s_values[] = {' % (enum.tag))
        for value in enum.values:
            print('    {"%s", %s},' % (value, value))
        print('};')
        print()
        print('static const trace::EnumSig _enum%s_sig = {' % (enum.tag))
        print('    %u, %u, _enum%s_values' % (enum.id, len(enum.values), enum.tag))
        print('};')
        print()

    def visitBitmask(self, bitmask):
        print('static const trace::BitmaskFlag _bitmask%s_flags[] = {' % (bitmask.tag))
        for value in bitmask.values:
            print('    {"%s", %s},' % (value, value))
        print('};')
        print()
        print('static const trace::BitmaskSig _bitmask%s_sig = {' % (bitmask.tag))
        print('    %u, %u, _bitmask%s_flags' % (bitmask.id, len(bitmask.values), bitmask.tag))
        print('};')
        print()

    def visitPointer(self, pointer):
        self.visit(pointer.type)

    def visitIntPointer(self, pointer):
        pass

    def visitObjPointer(self, pointer):
        self.visit(pointer.type)

    def visitLinearPointer(self, pointer):
        self.visit(pointer.type)

    def visitHandle(self, handle):
        self.visit(handle.type)

    def visitReference(self, reference):
        self.visit(reference.type)

    def visitAlias(self, alias):
        self.visit(alias.type)

    def visitOpaque(self, opaque):
        pass

    def visitInterface(self, interface):
        pass

    def visitPolymorphic(self, polymorphic):
        if not polymorphic.contextLess:
            return
        print('static void _write__%s(int selector, %s const & value) {' % (polymorphic.tag, polymorphic.expr))
        print('    switch (selector) {')
        for cases, type in polymorphic.iterSwitch():
            for case in cases:
                print('    %s:' % case)
            self.serializer.visit(type, '(%s)(value)' % (type,))
            print('        break;')
        print('    }')
        print('}')
        print()


class ValueSerializer(stdapi.Visitor, stdapi.ExpanderMixin):
    '''Visitor which generates code to serialize any type.
    
    Simple types are serialized inline here, whereas the serialization of
    complex types is dispatched to the serialization functions generated by
    ComplexValueSerializer visitor above.
    '''

    def visitLiteral(self, literal, instance):
        print('    trace::localWriter.write%s(%s);' % (literal.kind, instance))

    def visitString(self, string, instance):
        if not string.wide:
            cast = 'const char *'
            suffix = 'String'
        else:
            cast = 'const wchar_t *'
            suffix = 'WString'
        if cast != string.expr:
            # reinterpret_cast is necessary for GLubyte * <=> char *
            instance = 'reinterpret_cast<%s>(%s)' % (cast, instance)
        if string.length is not None:
            length = ', %s' % self.expand(string.length)
        else:
            length = ''
        print('    trace::localWriter.write%s(%s%s);' % (suffix, instance, length))

    def visitConst(self, const, instance):
        self.visit(const.type, instance)

    def visitStruct(self, struct, instance):
        print('    trace::localWriter.beginStruct(&_struct%s_sig);' % (struct.tag,))
        for member in struct.members:
            self.visitMember(member, instance)
        print('    trace::localWriter.endStruct();')

    def visitArray(self, array, instance):
        length = '_c' + array.type.tag
        index = '_i' + array.type.tag
        array_length = self.expand(array.length)
        print('    if (%s) {' % instance)
        print('        size_t %s = %s > 0 ? %s : 0;' % (length, array_length, array_length))
        print('        trace::localWriter.beginArray(%s);' % length)
        print('        for (size_t %s = 0; %s < %s; ++%s) {' % (index, index, length, index))
        print('            trace::localWriter.beginElement();')
        self.visitElement(index, array.type, '(%s)[%s]' % (instance, index))
        print('            trace::localWriter.endElement();')
        print('        }')
        print('        trace::localWriter.endArray();')
        print('    } else {')
        print('        trace::localWriter.writeNull();')
        print('    }')

    def visitAttribArray(self, array, instance):
        # For each element, decide if it is a key or a value (which depends on the previous key).
        # If it is a value, store it as the right type - usually int, some bitfield, or some enum.
        # It is currently assumed that an unknown key means that it is followed by an int value.

        # determine the array length which must be passed to writeArray() up front
        count = '_c' + array.baseType.tag
        print('    {')
        print('    int %s;' % count)
        print('    for (%(c)s = 0; %(array)s && %(array)s[%(c)s] != %(terminator)s; %(c)s += 2) {' \
              % {'c': count, 'array': instance, 'terminator': array.terminator})
        if array.hasKeysWithoutValues:
            print('        switch (int(%(array)s[%(c)s])) {' % {'array': instance, 'c': count})
            for key, valueType in array.valueTypes:
                if valueType is None:
                    print('        case %s:' % key)
            print('            %s--;' % count) # the next value is a key again and checked if it's the terminator
            print('            break;')
            print('        }')
        print('    }')
        print('    %(c)s += %(array)s ? 1 : 0;' % {'c': count, 'array': instance})
        print('    trace::localWriter.beginArray(%s);' % count)

        # for each key / key-value pair write the key and the value, if the key requires one

        index = '_i' + array.baseType.tag
        print('    for (int %(i)s = 0; %(i)s < %(count)s; %(i)s++) {' % {'i': index, 'count': count})
        print('        trace::localWriter.beginElement();')
        self.visit(array.baseType, "%(array)s[%(i)s]" % {'array': instance, 'i': index})
        print('        trace::localWriter.endElement();')
        print('        if (%(i)s + 1 >= %(count)s) {' % {'i': index, 'count': count})
        print('            break;')
        print('        }')
        print('        switch (int(%(array)s[%(i)s++])) {' % {'array': instance, 'i': index})
        # write generic value the usual way
        for key, valueType in array.valueTypes:
            if valueType is not None:
                print('        case %s:' % key)
                print('            trace::localWriter.beginElement();')
                self.visitElement(index, valueType, '(%(array)s)[%(i)s]' % {'array': instance, 'i': index})
                print('            trace::localWriter.endElement();')
                print('            break;')
        # known key with no value, just decrease the index so we treat the next value as a key
        if array.hasKeysWithoutValues:
            for key, valueType in array.valueTypes:
                if valueType is None:
                    print('        case %s:' % key)
            print('            %s--;' % index)
            print('            break;')
        # unknown key, write an int value
        print('        default:')
        print('            trace::localWriter.beginElement();')
        print('            os::log("apitrace: warning: %s: unknown key 0x%04X, interpreting value as int\\n", ' + \
                           '__FUNCTION__, int(%(array)s[%(i)s - 1]));'  % {'array': instance, 'i': index})
        print('            trace::localWriter.writeSInt(%(array)s[%(i)s]);' % {'array': instance, 'i': index})
        print('            trace::localWriter.endElement();')
        print('            break;')
        print('        }')
        print('    }')
        print('    trace::localWriter.endArray();')
        print('    }')


    def visitBlob(self, blob, instance):
        print('    trace::localWriter.writeBlob(%s, %s);' % (instance, self.expand(blob.size)))

    def visitEnum(self, enum, instance):
        print('    trace::localWriter.writeEnum(&_enum%s_sig, %s);' % (enum.tag, instance))

    def visitBitmask(self, bitmask, instance):
        print('    trace::localWriter.writeBitmask(&_bitmask%s_sig, %s);' % (bitmask.tag, instance))

    def visitPointer(self, pointer, instance):
        print('    if (%s) {' % instance)
        print('        trace::localWriter.beginArray(1);')
        print('        trace::localWriter.beginElement();')
        self.visit(pointer.type, "*" + instance)
        print('        trace::localWriter.endElement();')
        print('        trace::localWriter.endArray();')
        print('    } else {')
        print('        trace::localWriter.writeNull();')
        print('    }')

    def visitIntPointer(self, pointer, instance):
        print('    trace::localWriter.writePointer((uintptr_t)%s);' % instance)

    def visitObjPointer(self, pointer, instance):
        print('    trace::localWriter.writePointer((uintptr_t)%s);' % instance)

    def visitLinearPointer(self, pointer, instance):
        print('    trace::localWriter.writePointer((uintptr_t)%s);' % instance)

    def visitReference(self, reference, instance):
        self.visit(reference.type, instance)

    def visitHandle(self, handle, instance):
        self.visit(handle.type, instance)

    def visitAlias(self, alias, instance):
        self.visit(alias.type, instance)

    def visitOpaque(self, opaque, instance):
        print('    trace::localWriter.writePointer((uintptr_t)%s);' % instance)

    def visitInterface(self, interface, instance):
        assert False

    def visitPolymorphic(self, polymorphic, instance):
        if polymorphic.contextLess:
            print('    _write__%s(%s, %s);' % (polymorphic.tag, polymorphic.switchExpr, instance))
        else:
            switchExpr = self.expand(polymorphic.switchExpr)
            print('    switch (%s) {' % switchExpr)
            for cases, type in polymorphic.iterSwitch():
                for case in cases:
                    print('    %s:' % case)
                caseInstance = instance
                if type.expr is not None:
                    caseInstance = 'static_cast<%s>(%s)' % (type, caseInstance)
                self.visit(type, caseInstance)
                print('        break;')
            if polymorphic.defaultType is None:
                print(r'    default:')
                print(r'        os::log("apitrace: warning: %%s: unexpected polymorphic case %%i\n", __FUNCTION__, (int)%s);' % (switchExpr,))
                print(r'        trace::localWriter.writeNull();')
                print(r'        break;')
            print('    }')


class WrapDecider(stdapi.Traverser):
    '''Type visitor which will decide wheter this type will need wrapping or not.
    
    For complex types (arrays, structures), we need to know this before hand.
    '''

    def __init__(self):
        self.needsWrapping = False

    def visitLinearPointer(self, void):
        pass

    def visitObjPointer(self, interface):
        self.needsWrapping = True


class ValueWrapper(stdapi.Traverser, stdapi.ExpanderMixin):
    '''Type visitor which will generate the code to wrap an instance.
    
    Wrapping is necessary mostly for interfaces, however interface pointers can
    appear anywhere inside complex types.
    '''

    def visitStruct(self, struct, instance):
        for member in struct.members:
            self.visitMember(member, instance)

    def visitArray(self, array, instance):
        array_length = self.expand(array.length)
        print("    if (%s) {" % instance)
        print("        for (size_t _i = 0, _s = %s; _i < _s; ++_i) {" % array_length)
        self.visitElement('_i', array.type, instance + "[_i]")
        print("        }")
        print("    }")

    def visitPointer(self, pointer, instance):
        print("    if (%s) {" % instance)
        self.visit(pointer.type, "*" + instance)
        print("    }")
    
    def visitObjPointer(self, pointer, instance):
        elem_type = pointer.type.mutable()
        if isinstance(elem_type, stdapi.Interface):
            self.visitInterfacePointer(elem_type, instance)
        elif isinstance(elem_type, stdapi.Alias) and isinstance(elem_type.type, stdapi.Interface):
            self.visitInterfacePointer(elem_type.type, instance)
        else:
            # All interfaces should at least implement IUnknown
            print("    WrapIUnknown::_wrap(__FUNCTION__, (IUnknown **) &%s);" % (instance,))
    
    def visitInterface(self, interface, instance):
        raise NotImplementedError

    def visitInterfacePointer(self, interface, instance):
        print("    Wrap%s::_wrap(__FUNCTION__, &%s);" % (interface.name, instance))
    
    def visitPolymorphic(self, type, instance):
        # XXX: There might be polymorphic values that need wrapping in the future
        raise NotImplementedError


class ValueUnwrapper(ValueWrapper):
    '''Reverse of ValueWrapper.'''

    allocated = False

    def visitStruct(self, struct, instance):
        if not self.allocated:
            # Argument is constant. We need to create a non const
            print('    {')
            print("        %s * _t = static_cast<%s *>(alloca(sizeof *_t));" % (struct, struct))
            print('        *_t = %s;' % (instance,))
            assert instance.startswith('*')
            print('        %s = _t;' % (instance[1:],))
            instance = '*_t'
            self.allocated = True
            try:
                return ValueWrapper.visitStruct(self, struct, instance)
            finally:
                print('    }')
        else:
            return ValueWrapper.visitStruct(self, struct, instance)

    def visitArray(self, array, instance):
        if self.allocated or isinstance(instance, stdapi.Interface):
            return ValueWrapper.visitArray(self, array, instance)
        array_length = self.expand(array.length)
        elem_type = array.type.mutable()
        print("    if (%s && %s) {" % (instance, array_length))
        print("        %s * _t = static_cast<%s *>(alloca(%s * sizeof *_t));" % (elem_type, elem_type, array_length))
        print("        for (size_t _i = 0, _s = %s; _i < _s; ++_i) {" % array_length)
        print("            _t[_i] = %s[_i];" % instance) 
        self.allocated = True
        self.visit(array.type, "_t[_i]")
        print("        }")
        print("        %s = _t;" % instance)
        print("    }")

    def visitInterfacePointer(self, interface, instance):
        print(r'    Wrap%s::_unwrap(__FUNCTION__, &%s);' % (interface.name, instance))


def _getInterfaceHierarchy(allIfaces, baseIface, result):
    for iface in allIfaces:
        if iface.base is baseIface:
            _getInterfaceHierarchy(allIfaces, iface, result)
            result.append(iface)

def getInterfaceHierarchy(allIfaces, baseIface):
    result = []
    _getInterfaceHierarchy(allIfaces, baseIface, result)
    return result


class Tracer:
    '''Base class to orchestrate the code generation of API tracing.'''

    # 0-3 are reserved to memcpy, malloc, free, and realloc
    __id = 4

    def __init__(self):
        self.api = None

    def serializerFactory(self):
        '''Create a serializer.
        
        Can be overriden by derived classes to inject their own serialzer.
        '''

        return ValueSerializer()

    def traceApi(self, api):
        self.api = api

        self.header(api)

        # Includes
        for module in api.modules:
            for header in module.headers:
                print(header)
        print()

        # Generate the serializer functions
        types = api.getAllTypes()
        visitor = ComplexValueSerializer(self.serializerFactory())
        
        for tp in types:
            visitor.visit(tp)
        
        print()

        # Interfaces wrapers
        self.traceInterfaces(api)

        # Function wrappers
        self.interface = None
        self.base = None
        for function in api.getAllFunctions():
            self.traceFunctionDecl(function)
        for function in api.getAllFunctions():
            try:
                self.traceFunctionImpl(function)
            except:
                sys.stderr.write("error: %s: exception\n" % function.name)
                raise
        print()

        self.footer(api)

    def header(self, api):
        print('#ifdef _WIN32')
        print('#  include <malloc.h> // alloca')
        print('#  ifndef alloca')
        print('#    define alloca _alloca')
        print('#  endif')
        print('#else')
        print('#  include <alloca.h> // alloca')
        print('#endif')
        print()
        print()
        print(r'/*')
        print(r' * g_WrappedObjects is already protected by trace::LocalWriter::mutex')
        print(r' * This lock is hold during the beginEnter/endEnter and beginLeave/endLeave sections')
        print(r' */')
        print('static std::map<void *, void *> g_WrappedObjects;')

    def footer(self, api):
        pass

    def traceFunctionDecl(self, function):
        # Per-function declarations

        if not function.internal:
            if function.args:
                print('static const char * _%s_args[%u] = {%s};' % (function.name, len(function.args), ', '.join(['"%s"' % arg.name for arg in function.args])))
            else:
                print('static const char ** _%s_args = NULL;' % (function.name,))
            print('static const trace::FunctionSig _%s_sig = {%u, "%s", %u, _%s_args};' % (function.name, self.getFunctionSigId(), function.sigName(), len(function.args), function.name))
            print()

    def getFunctionSigId(self):
        id = Tracer.__id
        Tracer.__id += 1
        return id

    def isFunctionPublic(self, function):
        return True

    def traceFunctionImpl(self, function):
        if self.isFunctionPublic(function):
            print('extern "C" PUBLIC')
        else:
            print('extern "C" PRIVATE')
        print(function.prototype() + ' {')
        if function.type is not stdapi.Void:
            print('    %s _result;' % function.type)

        for arg in function.args:
            if not arg.output:
                self.unwrapArg(function, arg)

        self.traceFunctionImplBody(function)

        # XXX: wrapping should go here, but before we can do that we'll need to protect g_WrappedObjects with its own mutex

        if function.type is not stdapi.Void:
            print('    return _result;')

        print('}')
        print()

    def traceFunctionImplBody(self, function):
        if not function.internal:
            print('    unsigned _call = trace::localWriter.beginEnter(&_%s_sig);' % (function.name,))
            for arg in function.args:
                if not arg.output:
                    self.serializeArg(function, arg)
            print('    trace::localWriter.endEnter();')
        self.invokeFunction(function)
        if not function.internal:
            print('    trace::localWriter.beginLeave(_call);')
            print('    if (%s) {' % self.wasFunctionSuccessful(function))
            for arg in function.args:
                if arg.output:
                    self.serializeArg(function, arg)
                    self.wrapArg(function, arg)
            print('    }')
            if function.type is not stdapi.Void:
                self.serializeRet(function, "_result")
            if function.type is not stdapi.Void:
                self.wrapRet(function, "_result")
            print('    trace::localWriter.endLeave();')

    def invokeFunction(self, function):
        self.doInvokeFunction(function)

    def doInvokeFunction(self, function, prefix='_', suffix=''):
        # Same as invokeFunction() but called both when trace is enabled or disabled.
        if function.type is stdapi.Void:
            result = ''
        else:
            result = '_result = '
        dispatch = prefix + function.name + suffix
        print('    %s%s(%s);' % (result, dispatch, ', '.join([str(arg.name) for arg in function.args])))

    def wasFunctionSuccessful(self, function):
        if function.type is stdapi.Void:
            return 'true'
        if str(function.type) == 'HRESULT':
            return 'SUCCEEDED(_result)'
        return 'true'

    def serializeArg(self, function, arg):
        print('    trace::localWriter.beginArg(%u);' % (arg.index,))
        self.serializeArgValue(function, arg)
        print('    trace::localWriter.endArg();')

    def serializeArgValue(self, function, arg):
        self.serializeValue(arg.type, arg.name)

    def wrapArg(self, function, arg):
        assert not isinstance(arg.type, stdapi.ObjPointer)

        from specs.winapi import REFIID
        riid = None
        for other_arg in function.args:
            if not other_arg.output and other_arg.type is REFIID:
                riid = other_arg
        if riid is not None \
           and riid.name != 'EmulatedInterface' \
           and isinstance(arg.type, stdapi.Pointer) \
           and isinstance(arg.type.type, stdapi.ObjPointer):
            self.wrapIid(function, riid, arg)
            return

        self.wrapValue(arg.type, arg.name)

    def unwrapArg(self, function, arg):
        self.unwrapValue(arg.type, arg.name)

    def serializeRet(self, function, instance):
        print('    trace::localWriter.beginReturn();')
        self.serializeValue(function.type, instance)
        print('    trace::localWriter.endReturn();')

    def serializeValue(self, type, instance):
        serializer = self.serializerFactory()
        serializer.visit(type, instance)

    def wrapRet(self, function, instance):
        self.wrapValue(function.type, instance)

    def needsWrapping(self, type):
        visitor = WrapDecider()
        visitor.visit(type)
        return visitor.needsWrapping

    def wrapValue(self, type, instance):
        if self.needsWrapping(type):
            visitor = ValueWrapper()
            visitor.visit(type, instance)

    def unwrapValue(self, type, instance):
        if self.needsWrapping(type):
            visitor = ValueUnwrapper()
            visitor.visit(type, instance)

    def traceInterfaces(self, api):
        interfaces = api.getAllInterfaces()
        if not interfaces:
            return

        print(r'#include "guids.hpp"')
        print()

        # Helper functions to wrap/unwrap interface pointers
        print(r'static inline bool')
        print(r'hasChildInterface(REFIID riid, IUnknown *pUnknown) {')
        print(r'    IUnknown *pObj = NULL;')
        print(r'    HRESULT hr = pUnknown->QueryInterface(riid, (VOID **)&pObj);')
        print(r'    if (FAILED(hr)) {')
        print(r'        return false;')
        print(r'    }')
        print(r'    assert(pObj);')
        print(r'    pObj->Release();')
        print(r'    return pUnknown == pObj;')
        print(r'}')
        print()
        print(r'static inline const void *')
        print(r'getVtbl(const void *pvObj) {')
        print(r'    return pvObj ? *(const void **)pvObj : NULL;')
        print(r'}')
        print()
        print(r'static void')
        print(r'warnVtbl(const void *pVtbl) {')
        print(r'    HMODULE hModule = 0;')
        print(r'    BOOL bRet = GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |')
        print(r'                                  GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,')
        print(r'                                  (LPCTSTR)pVtbl,')
        print(r'                                  &hModule);')
        print(r'    if (bRet) {')
        print(r'        char szModule[MAX_PATH];')
        print(r'        DWORD dwRet = GetModuleFileNameA(hModule, szModule, sizeof szModule);')
        print(r'        assert(dwRet);')
        print(r'        if (dwRet) {')
        print(r'            DWORD dwOffset = (UINT_PTR)pVtbl - (UINT_PTR)hModule;')
        print(r'            os::log("apitrace: warning: pVtbl = %p (%s!+0x%0lx)\n", pVtbl, szModule, dwOffset);')
        print(r'        } else {')
        print(r'            os::log("apitrace: warning: pVtbl = %p\n", pVtbl);')
        print(r'        }')
        print(r'    }')
        print(r'}')
        print() 

        for iface in interfaces:
            self.declareWrapperInterface(iface)

        self.implementIidWrapper(api)
        
        for iface in interfaces:
            self.implementWrapperInterface(iface)
        
        print()

    def declareWrapperInterface(self, interface):
        wrapperInterfaceName = getWrapperInterfaceName(interface)
        print("class %s : public %s " % (wrapperInterfaceName, interface.name))
        print("{")
        print("private:")
        print("    %s(%s * pInstance);" % (wrapperInterfaceName, interface.name))
        print("    ~%s(); // Not implemented" % wrapperInterfaceName)
        print("public:")
        print("    static %s* _create(const char *entryName, %s * pInstance);" % (wrapperInterfaceName, interface.name))
        print("    static void _wrap(const char *entryName, %s ** ppInstance);" % (interface.name,))
        print("    static void _unwrap(const char *entryName, %s ** pInstance);" % (interface.name,))
        print()

        methods = list(interface.iterMethods())
        for method in methods:
            print("    " + method.prototype() + " override;")
        print()

        for type, name, value in self.enumWrapperInterfaceVariables(interface):
            print('    %s %s;' % (type, name))
        print()

        print(r'private:')
        print(r'    void _dummy(unsigned i) const {')
        print(r'        os::log("error: %%s: unexpected virtual method %%i of instance pvObj=%%p pWrapper=%%p pVtbl=%%p\n", "%s", i, m_pInstance, this, m_pVtbl);' % interface.name)
        print(r'        warnVtbl(m_pVtbl);')
        print(r'        warnVtbl(getVtbl(m_pInstance));')
        print(r'        trace::localWriter.flush();')
        print(r'        os::abort();')
        print(r'    }')
        print()
        for i in range(len(methods), 64):
            print(r'    virtual void _dummy%i(void) const { _dummy(%i); }' % (i, i))
        print()

        print("};")
        print()

    def enumWrapperInterfaceVariables(self, interface):
        return [
            ("DWORD", "m_dwMagic", "0xd8365d6c"),
            ("%s *" % interface.name, "m_pInstance", "pInstance"),
            ("const void *", "m_pVtbl", "getVtbl(pInstance)"),
            ("UINT", "m_NumMethods", len(list(interface.iterBaseMethods()))),
        ] 

    def implementWrapperInterface(self, iface):
        self.interface = iface

        wrapperInterfaceName = getWrapperInterfaceName(iface)

        # Private constructor
        print('%s::%s(%s * pInstance) {' % (wrapperInterfaceName, wrapperInterfaceName, iface.name))
        for type, name, value in self.enumWrapperInterfaceVariables(iface):
            if value is not None:
                print('    %s = %s;' % (name, value))
        print('}')
        print()

        # Public constructor
        print('%s *%s::_create(const char *entryName, %s * pInstance) {' % (wrapperInterfaceName, wrapperInterfaceName, iface.name))
        print(r'    Wrap%s *pWrapper = new Wrap%s(pInstance);' % (iface.name, iface.name))
        if debug:
            print(r'    os::log("%%s: created %s pvObj=%%p pWrapper=%%p pVtbl=%%p\n", entryName, pInstance, pWrapper, pWrapper->m_pVtbl);' % iface.name)
        print(r'    g_WrappedObjects[pInstance] = pWrapper;')
        print(r'    return pWrapper;')
        print('}')
        print()

        baseMethods = list(iface.iterBaseMethods())
        for base, method in baseMethods:
            self.base = base
            self.implementWrapperInterfaceMethod(iface, base, method)

        print()

        # Wrap pointer
        ifaces = self.api.getAllInterfaces()
        print(r'void')
        print(r'%s::_wrap(const char *entryName, %s **ppObj) {' % (wrapperInterfaceName, iface.name))
        print(r'    if (!ppObj) {')
        print(r'        return;')
        print(r'    }')
        print(r'    %s *pObj = *ppObj;' % (iface.name,))
        print(r'    if (!pObj) {')
        print(r'        return;')
        print(r'    }')
        print(r'    assert(hasChildInterface(IID_%s, pObj));' % iface.name)
        print(r'    std::map<void *, void *>::const_iterator it = g_WrappedObjects.find(pObj);')
        print(r'    if (it != g_WrappedObjects.end()) {')
        print(r'        Wrap%s *pWrapper = (Wrap%s *)it->second;' % (iface.name, iface.name))
        print(r'        assert(pWrapper);')
        print(r'        assert(pWrapper->m_dwMagic == 0xd8365d6c);')
        print(r'        assert(pWrapper->m_pInstance == pObj);')
        print(r'        if (pWrapper->m_pVtbl == getVtbl(pObj) &&')
        print(r'            pWrapper->m_NumMethods >= %s) {' % len(baseMethods))
        if debug:
            print(r'            os::log("%s: fetched pvObj=%p pWrapper=%p pVtbl=%p\n", entryName, pObj, pWrapper, pWrapper->m_pVtbl);')
        print(r'            assert(hasChildInterface(IID_%s, pWrapper->m_pInstance));' % iface.name)
        print(r'            *ppObj = pWrapper;')
        print(r'            return;')
        print(r'        } else {')
        if debug:
            print(r'            os::log("%s::Release: deleted pvObj=%%p pWrapper=%%p pVtbl=%%p\n", pWrapper->m_pInstance, pWrapper, pWrapper->m_pVtbl);' % iface.name)
        print(r'            g_WrappedObjects.erase(pObj);')
        print(r'        }')
        print(r'    }')
        for childIface in getInterfaceHierarchy(ifaces, iface):
            print(r'    if (hasChildInterface(IID_%s, pObj)) {' % (childIface.name,))
            print(r'        *ppObj = Wrap%s::_create(entryName, static_cast<%s *>(pObj));' % (childIface.name, childIface.name))
            print(r'        return;')
            print(r'    }')
        print(r'    *ppObj = Wrap%s::_create(entryName, pObj);' % iface.name)
        print(r'}')
        print()

        # Unwrap pointer
        print(r'void')
        print(r'%s::_unwrap(const char *entryName, %s **ppObj) {' % (wrapperInterfaceName, iface.name))
        print(r'    if (!ppObj || !*ppObj) {')
        print(r'        return;')
        print(r'    }')
        print(r'    const %s *pWrapper = static_cast<const %s*>(*ppObj);' % (wrapperInterfaceName, getWrapperInterfaceName(iface)))
        print(r'    if (pWrapper && pWrapper->m_dwMagic == 0xd8365d6c) {')
        print(r'        *ppObj = pWrapper->m_pInstance;')
        print(r'    } else {')
        print(r'        os::log("apitrace: warning: %%s: unexpected %%s pointer %%p\n", entryName, "%s", *ppObj);' % iface.name)
        print(r'        trace::localWriter.flush();')
        print(r'    }')
        print(r'}')
        print()

    def implementWrapperInterfaceMethod(self, interface, base, method):
        wrapperInterfaceName = getWrapperInterfaceName(interface)

        print(method.prototype(wrapperInterfaceName + '::' + method.name) + ' {')

        if False:
            print(r'    os::log("%%s(%%p -> %%p)\n", "%s", this, m_pInstance);' % (wrapperInterfaceName + '::' + method.name))

        if method.type is not stdapi.Void:
            print('    %s _result;' % method.type)
    
        print('    %s *_this = static_cast<%s *>(m_pInstance);' % (base, base))
        for arg in method.args:
            if not arg.output:
                self.unwrapArg(method, arg)

        self.implementWrapperInterfaceMethodBody(interface, base, method)

        # XXX: wrapping should go here, but before we can do that we'll need to protect g_WrappedObjects with its own mutex

        if method.type is not stdapi.Void:
            print('    return _result;')

        print('}')
        print()

    def implementWrapperInterfaceMethodBody(self, interface, base, method):
        assert not method.internal

        sigName = interface.name + '::' + method.sigName()
        if method.overloaded:
            # Once the method signature name goes into a trace, we'll need to
            # support it indefinetely, so log them so one can make sure nothing
            # weird gets baked in
            sys.stderr.write('note: overloaded method %s\n' % (sigName,))

        numArgs = len(method.args) + 1
        print('    static const char * _args[%u] = {%s};' % (numArgs, ', '.join(['"this"'] + ['"%s"' % arg.name for arg in method.args])))
        print('    static const trace::FunctionSig _sig = {%u, "%s", %u, _args};' % (self.getFunctionSigId(), sigName, numArgs))

        print('    unsigned _call = trace::localWriter.beginEnter(&_sig);')
        print('    trace::localWriter.beginArg(0);')
        print('    trace::localWriter.writePointer((uintptr_t)m_pInstance);')
        print('    trace::localWriter.endArg();')
        for arg in method.args:
            if not arg.output:
                self.serializeArg(method, arg)
        print('    trace::localWriter.endEnter();')
        
        self.invokeMethod(interface, base, method)

        print('    trace::localWriter.beginLeave(_call);')

        print('    if (%s) {' % self.wasFunctionSuccessful(method))
        for arg in method.args:
            if arg.output:
                self.serializeArg(method, arg)
                self.wrapArg(method, arg)
        print('    }')

        if method.type is not stdapi.Void:
            self.serializeRet(method, '_result')
        if method.type is not stdapi.Void:
            self.wrapRet(method, '_result')

        if method.name == 'Release':
            assert method.type is not stdapi.Void
            print(r'    if (!_result) {')
            print(r'        // NOTE: Must not delete the wrapper here.  See')
            print(r'        // https://github.com/apitrace/apitrace/issues/462')
            print(r'    }')
        
        print('    trace::localWriter.endLeave();')

    def implementIidWrapper(self, api):
        ifaces = api.getAllInterfaces()

        print(r'static void')
        print(r'warnIID(const char *entryName, REFIID riid, void *pvObj, const char *reason) {')
        print(r'    os::log("apitrace: warning: %s: %s IID %s\n",')
        print(r'            entryName, reason,')
        print(r'            getGuidName(riid));')
        print(r'    const void * pVtbl = getVtbl(pvObj);')
        print(r'    warnVtbl(pVtbl);')
        print(r'}')
        print() 
        print(r'static void')
        print(r'wrapIID(const char *entryName, REFIID riid, void * * ppvObj) {')
        print(r'    if (!ppvObj || !*ppvObj) {')
        print(r'        return;')
        print(r'    }')
        for iface in ifaces:
            print(r'    if (riid == IID_%s) {' % (iface.name,))
            print(r'        Wrap%s::_wrap(entryName, (%s **) ppvObj);' % (iface.name, iface.name))
            print(r'        return;')
            print(r'    }')
        print(r'    warnIID(entryName, riid, *ppvObj, "unsupported");')
        print(r'}')
        print()

    def wrapIid(self, function, riid, out):
        # Cast output arg to `void **` if necessary
        out_name = out.name
        obj_type = out.type.type.type
        if not obj_type is stdapi.Void:
            assert isinstance(obj_type, stdapi.Interface)
            out_name = 'reinterpret_cast<void * *>(%s)' % out_name

        print(r'    if (%s && *%s) {' % (out.name, out.name))
        functionName = function.name
        else_ = ''
        if self.interface is not None:
            functionName = self.interface.name + '::' + functionName
            print(r'        if (*%s == m_pInstance &&' % (out_name,))
            print(r'            (%s)) {' % ' || '.join('%s == IID_%s' % (riid.name, iface.name) for iface in self.interface.iterBases()))
            print(r'            *%s = this;' % (out_name,))
            print(r'        }')
            else_ = 'else '
        print(r'        %s{' % else_)
        print(r'             wrapIID("%s", %s, %s);' % (functionName, riid.name, out_name))
        print(r'        }')
        print(r'    }')

    def invokeMethod(self, interface, base, method):
        if method.type is stdapi.Void:
            result = ''
        else:
            result = '_result = '
        print('    %s_this->%s(%s);' % (result, method.name, ', '.join([str(arg.name) for arg in method.args])))
    
    def emit_memcpy(self, ptr, size):
        print('    trace::fakeMemcpy(%s, %s);' % (ptr, size))
    
    def fake_call(self, function, args):
        print('        {')
        print('            unsigned _fake_call = trace::localWriter.beginEnter(&_%s_sig, true);' % (function.name,))
        for arg, instance in zip(function.args, args):
            assert not arg.output
            print('            trace::localWriter.beginArg(%u);' % (arg.index,))
            self.serializeValue(arg.type, instance)
            print('            trace::localWriter.endArg();')
        print('            trace::localWriter.endEnter();')
        print('            trace::localWriter.beginLeave(_fake_call);')
        print('            trace::localWriter.endLeave();')
        print('        }')