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gecko-dev/js/ctypes/Function.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is js-ctypes.
*
* The Initial Developer of the Original Code is
* The Mozilla Foundation <http://www.mozilla.org/>.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Mark Finkle <mark.finkle@gmail.com>, <mfinkle@mozilla.com>
* Fredrik Larsson <nossralf@gmail.com>
* Dan Witte <dwitte@mozilla.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "jscntxt.h"
#include "Function.h"
#include "Library.h"
#include "nsAutoPtr.h"
namespace mozilla {
namespace ctypes {
/*******************************************************************************
** Static helpers
*******************************************************************************/
template<class IntegerType>
static IntegerType
Convert(jsdouble d)
{
return IntegerType(d);
}
#ifdef _MSC_VER
// MSVC can't perform double to unsigned __int64 conversion when the
// double is greater than 2^63 - 1. Help it along a little.
template<>
static PRUint64
Convert<PRUint64>(jsdouble d)
{
return d > 0x7fffffffffffffffui64 ?
PRUint64(d - 0x8000000000000000ui64) + 0x8000000000000000ui64 :
PRUint64(d);
}
#endif
template<class IntegerType>
static bool
jsvalToIntStrict(jsval aValue, IntegerType *aResult)
{
if (JSVAL_IS_INT(aValue)) {
jsint i = JSVAL_TO_INT(aValue);
*aResult = IntegerType(i);
// Make sure the integer fits in the alotted precision, and has the right sign.
return jsint(*aResult) == i &&
(i < 0) == (*aResult < 0);
}
if (JSVAL_IS_DOUBLE(aValue)) {
jsdouble d = *JSVAL_TO_DOUBLE(aValue);
*aResult = Convert<IntegerType>(d);
// Don't silently lose bits here -- check that aValue really is an
// integer value, and has the right sign.
return jsdouble(*aResult) == d &&
(d < 0) == (*aResult < 0);
}
if (JSVAL_IS_BOOLEAN(aValue)) {
// Implicitly promote boolean values to 0 or 1, like C.
*aResult = JSVAL_TO_BOOLEAN(aValue);
NS_ASSERTION(*aResult == 0 || *aResult == 1, "invalid boolean");
return true;
}
// Don't silently convert null to an integer. It's probably a mistake.
return false;
}
static bool
jsvalToDoubleStrict(jsval aValue, jsdouble *dp)
{
// Don't silently convert true to 1.0 or false to 0.0, even though C/C++
// does it. It's likely to be a mistake.
if (JSVAL_IS_INT(aValue)) {
*dp = JSVAL_TO_INT(aValue);
return true;
}
if (JSVAL_IS_DOUBLE(aValue)) {
*dp = *JSVAL_TO_DOUBLE(aValue);
return true;
}
return false;
}
JSErrorFormatString ErrorFormatString[CTYPESERR_LIMIT] = {
#define MSG_DEF(name, number, count, exception, format) \
{ format, count, exception } ,
#include "ctypes.msg"
#undef MSG_DEF
};
const JSErrorFormatString*
GetErrorMessage(void* userRef, const char* locale, const uintN errorNumber)
{
if (0 < errorNumber && errorNumber < CTYPESERR_LIMIT)
return &ErrorFormatString[errorNumber];
return NULL;
}
static const char*
ToSource(JSContext* cx, jsval vp)
{
JSString* str = JS_ValueToSource(cx, vp);
if (str)
return JS_GetStringBytes(str);
JS_ClearPendingException(cx);
return "<<error converting value to string>>";
}
static bool
TypeError(JSContext* cx, const char* expected, jsval actual)
{
const char* src = ToSource(cx, actual);
JS_ReportErrorNumber(cx, GetErrorMessage, NULL,
CTYPESMSG_TYPE_ERROR, expected, src);
return false;
}
static bool
GetABI(JSContext* cx, jsval aCallType, ffi_abi& aResult)
{
ABICode abi = Module::GetABICode(cx, aCallType);
// determine the ABI from the subset of those available on the
// given platform. TYPE_DEFAULT specifies the default
// C calling convention (cdecl) on each platform.
switch (abi) {
case ABI_default_abi:
aResult = FFI_DEFAULT_ABI;
return true;
#if (defined(_WIN32) && !defined(_WIN64)) || defined(_OS2)
case ABI_stdcall_abi:
aResult = FFI_STDCALL;
return true;
#endif
default:
return false;
}
}
static bool
PrepareType(JSContext* aContext, jsval aType, Type& aResult)
{
aResult.mType = Module::GetTypeCode(aContext, aType);
switch (aResult.mType) {
case TYPE_void_t:
aResult.mFFIType = ffi_type_void;
break;
case TYPE_int8_t:
aResult.mFFIType = ffi_type_sint8;
break;
case TYPE_int16_t:
aResult.mFFIType = ffi_type_sint16;
break;
case TYPE_int32_t:
aResult.mFFIType = ffi_type_sint32;
break;
case TYPE_int64_t:
aResult.mFFIType = ffi_type_sint64;
break;
case TYPE_bool:
case TYPE_uint8_t:
aResult.mFFIType = ffi_type_uint8;
break;
case TYPE_uint16_t:
aResult.mFFIType = ffi_type_uint16;
break;
case TYPE_uint32_t:
aResult.mFFIType = ffi_type_uint32;
break;
case TYPE_uint64_t:
aResult.mFFIType = ffi_type_uint64;
break;
case TYPE_float:
aResult.mFFIType = ffi_type_float;
break;
case TYPE_double:
aResult.mFFIType = ffi_type_double;
break;
case TYPE_string:
case TYPE_ustring:
aResult.mFFIType = ffi_type_pointer;
break;
default:
JS_ReportError(aContext, "Invalid type specification");
return false;
}
return true;
}
static bool
PrepareValue(JSContext* aContext, const Type& aType, jsval aValue, Value& aResult)
{
jsdouble d;
switch (aType.mType) {
case TYPE_bool:
// Do not implicitly lose bits, but allow the values 0, 1, and -0.
// Programs can convert explicitly, if needed, using `Boolean(v)` or `!!v`.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mUint8) ||
aResult.mValue.mUint8 > 1)
return TypeError(aContext, "boolean", aValue);
aResult.mData = &aResult.mValue.mUint8;
break;
case TYPE_int8_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mInt8))
return TypeError(aContext, "int8", aValue);
aResult.mData = &aResult.mValue.mInt8;
break;
case TYPE_int16_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mInt16))
return TypeError(aContext, "int16", aValue);
aResult.mData = &aResult.mValue.mInt16;
break;
case TYPE_int32_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mInt32))
return TypeError(aContext, "int32", aValue);
aResult.mData = &aResult.mValue.mInt32;
break;
case TYPE_int64_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mInt64))
return TypeError(aContext, "int64", aValue);
aResult.mData = &aResult.mValue.mInt64;
break;
case TYPE_uint8_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mUint8))
return TypeError(aContext, "uint8", aValue);
aResult.mData = &aResult.mValue.mUint8;
break;
case TYPE_uint16_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mUint16))
return TypeError(aContext, "uint16", aValue);
aResult.mData = &aResult.mValue.mUint16;
break;
case TYPE_uint32_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mUint32))
return TypeError(aContext, "uint32", aValue);
aResult.mData = &aResult.mValue.mUint32;
break;
case TYPE_uint64_t:
// Do not implicitly lose bits.
if (!jsvalToIntStrict(aValue, &aResult.mValue.mUint64))
return TypeError(aContext, "uint64", aValue);
aResult.mData = &aResult.mValue.mUint64;
break;
case TYPE_float:
if (!jsvalToDoubleStrict(aValue, &d))
return TypeError(aContext, "float", aValue);
// The following cast silently throws away some bits, but there's
// no good way around it. Sternly requiring that the 64-bit double
// argument be exactly representable as a 32-bit float is
// unrealistic: it would allow 1/2 to pass but not 1/3.
aResult.mValue.mFloat = float(d);
aResult.mData = &aResult.mValue.mFloat;
break;
case TYPE_double:
if (!jsvalToDoubleStrict(aValue, &d))
return TypeError(aContext, "double", aValue);
aResult.mValue.mDouble = d;
aResult.mData = &aResult.mValue.mDouble;
break;
case TYPE_string:
if (JSVAL_IS_NULL(aValue)) {
// Allow passing a null pointer.
aResult.mValue.mPointer = nsnull;
} else if (JSVAL_IS_STRING(aValue)) {
aResult.mValue.mPointer = JS_GetStringBytes(JSVAL_TO_STRING(aValue));
} else {
// Don't implicitly convert to string. Users can implicitly convert
// with `String(x)` or `""+x`.
return TypeError(aContext, "string", aValue);
}
aResult.mData = &aResult.mValue.mPointer;
break;
case TYPE_ustring:
if (JSVAL_IS_NULL(aValue)) {
// Allow passing a null pointer.
aResult.mValue.mPointer = nsnull;
} else if (JSVAL_IS_STRING(aValue)) {
aResult.mValue.mPointer = JS_GetStringChars(JSVAL_TO_STRING(aValue));
} else {
// Don't implicitly convert to string. Users can implicitly convert
// with `String(x)` or `""+x`.
return TypeError(aContext, "ustring", aValue);
}
aResult.mData = &aResult.mValue.mPointer;
break;
default:
NS_NOTREACHED("invalid type");
return false;
}
return true;
}
static void
PrepareReturnValue(const Type& aType, Value& aResult)
{
switch (aType.mType) {
case TYPE_void_t:
aResult.mData = nsnull;
break;
case TYPE_int8_t:
aResult.mData = &aResult.mValue.mInt8;
break;
case TYPE_int16_t:
aResult.mData = &aResult.mValue.mInt16;
break;
case TYPE_int32_t:
aResult.mData = &aResult.mValue.mInt32;
break;
case TYPE_int64_t:
aResult.mData = &aResult.mValue.mInt64;
break;
case TYPE_bool:
case TYPE_uint8_t:
aResult.mData = &aResult.mValue.mUint8;
break;
case TYPE_uint16_t:
aResult.mData = &aResult.mValue.mUint16;
break;
case TYPE_uint32_t:
aResult.mData = &aResult.mValue.mUint32;
break;
case TYPE_uint64_t:
aResult.mData = &aResult.mValue.mUint64;
break;
case TYPE_float:
aResult.mData = &aResult.mValue.mFloat;
break;
case TYPE_double:
aResult.mData = &aResult.mValue.mDouble;
break;
case TYPE_string:
case TYPE_ustring:
aResult.mData = &aResult.mValue.mPointer;
break;
default:
NS_NOTREACHED("invalid type");
break;
}
}
static bool
ConvertReturnValue(JSContext* aContext,
const Type& aResultType,
const Value& aResultValue,
jsval* aValue)
{
switch (aResultType.mType) {
case TYPE_void_t:
*aValue = JSVAL_VOID;
break;
case TYPE_bool:
*aValue = aResultValue.mValue.mUint8 ? JSVAL_TRUE : JSVAL_FALSE;
break;
case TYPE_int8_t:
*aValue = INT_TO_JSVAL(aResultValue.mValue.mInt8);
break;
case TYPE_int16_t:
*aValue = INT_TO_JSVAL(aResultValue.mValue.mInt16);
break;
case TYPE_int32_t:
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mInt32), aValue))
return false;
break;
case TYPE_int64_t:
// Implicit conversion with loss of bits. :-[
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mInt64), aValue))
return false;
break;
case TYPE_uint8_t:
*aValue = INT_TO_JSVAL(aResultValue.mValue.mUint8);
break;
case TYPE_uint16_t:
*aValue = INT_TO_JSVAL(aResultValue.mValue.mUint16);
break;
case TYPE_uint32_t:
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mUint32), aValue))
return false;
break;
case TYPE_uint64_t:
// Implicit conversion with loss of bits. :-[
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mUint64), aValue))
return false;
break;
case TYPE_float:
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mFloat), aValue))
return false;
break;
case TYPE_double:
if (!JS_NewNumberValue(aContext, jsdouble(aResultValue.mValue.mDouble), aValue))
return false;
break;
case TYPE_string: {
if (!aResultValue.mValue.mPointer) {
// Allow returning a null pointer.
*aValue = JSVAL_NULL;
} else {
JSString *jsstring = JS_NewStringCopyZ(aContext,
reinterpret_cast<const char*>(aResultValue.mValue.mPointer));
if (!jsstring)
return false;
*aValue = STRING_TO_JSVAL(jsstring);
}
break;
}
case TYPE_ustring: {
if (!aResultValue.mValue.mPointer) {
// Allow returning a null pointer.
*aValue = JSVAL_NULL;
} else {
JSString *jsstring = JS_NewUCStringCopyZ(aContext,
reinterpret_cast<const jschar*>(aResultValue.mValue.mPointer));
if (!jsstring)
return false;
*aValue = STRING_TO_JSVAL(jsstring);
}
break;
}
default:
NS_NOTREACHED("invalid type");
return false;
}
return true;
}
/*******************************************************************************
** Function implementation
*******************************************************************************/
Function::Function()
: mNext(NULL)
{
}
Function::~Function()
{
}
bool
Function::Init(JSContext* aContext,
PRFuncPtr aFunc,
jsval aCallType,
jsval aResultType,
jsval* aArgTypes,
uintN aArgLength)
{
mFunc = aFunc;
// determine the ABI
if (!GetABI(aContext, aCallType, mCallType)) {
JS_ReportError(aContext, "Invalid ABI specification");
return false;
}
// prepare the result type
if (!PrepareType(aContext, aResultType, mResultType))
return false;
// prepare the argument types
mArgTypes.SetCapacity(aArgLength);
for (PRUint32 i = 0; i < aArgLength; ++i) {
if (!PrepareType(aContext, aArgTypes[i], *mArgTypes.AppendElement()))
return false;
// disallow void argument types
if (mArgTypes[i].mType == TYPE_void_t) {
JS_ReportError(aContext, "Cannot have void argument type");
return false;
}
// ffi_prep_cif requires an array of ffi_types; prepare it separately.
mFFITypes.AppendElement(&mArgTypes[i].mFFIType);
}
ffi_status status = ffi_prep_cif(&mCIF, mCallType, mFFITypes.Length(),
&mResultType.mFFIType, mFFITypes.Elements());
switch (status) {
case FFI_OK:
return true;
case FFI_BAD_ABI:
JS_ReportError(aContext, "Invalid ABI specification");
return false;
case FFI_BAD_TYPEDEF:
JS_ReportError(aContext, "Invalid type specification");
return false;
default:
JS_ReportError(aContext, "Unknown libffi error");
return false;
}
}
bool
Function::Execute(JSContext* cx, PRUint32 argc, jsval* vp)
{
if (argc != mArgTypes.Length()) {
JS_ReportError(cx, "Number of arguments does not match declaration");
return false;
}
// prepare the values for each argument
nsAutoTArray<Value, 16> values;
for (PRUint32 i = 0; i < mArgTypes.Length(); ++i) {
if (!PrepareValue(cx, mArgTypes[i], JS_ARGV(cx, vp)[i], *values.AppendElement()))
return false;
}
// create an array of pointers to each value, for passing to ffi_call
nsAutoTArray<void*, 16> ffiValues;
for (PRUint32 i = 0; i < mArgTypes.Length(); ++i) {
ffiValues.AppendElement(values[i].mData);
}
// initialize a pointer to an appropriate location, for storing the result
Value resultValue;
PrepareReturnValue(mResultType, resultValue);
// suspend the request before we call into the function, since the call
// may block or otherwise take a long time to return.
jsrefcount rc = JS_SuspendRequest(cx);
ffi_call(&mCIF, FFI_FN(mFunc), resultValue.mData, ffiValues.Elements());
JS_ResumeRequest(cx, rc);
// prepare a JS object from the result
jsval rval;
if (!ConvertReturnValue(cx, mResultType, resultValue, &rval))
return false;
JS_SET_RVAL(cx, vp, rval);
return true;
}
/*******************************************************************************
** JSObject implementation
*******************************************************************************/
JSObject*
Function::Create(JSContext* aContext,
JSObject* aLibrary,
PRFuncPtr aFunc,
const char* aName,
jsval aCallType,
jsval aResultType,
jsval* aArgTypes,
uintN aArgLength)
{
// create new Function instance
nsAutoPtr<Function> self(new Function());
if (!self)
return NULL;
// deduce and check the ABI and parameter types
if (!self->Init(aContext, aFunc, aCallType, aResultType, aArgTypes, aArgLength))
return NULL;
// create and root the new JS function object
JSFunction* fn = JS_NewFunction(aContext, JSNative(Function::Call),
aArgLength, JSFUN_FAST_NATIVE, NULL, aName);
if (!fn)
return NULL;
JSObject* fnObj = JS_GetFunctionObject(fn);
JSAutoTempValueRooter fnRoot(aContext, fnObj);
// stash a pointer to self, which Function::Call will need at call time
if (!JS_SetReservedSlot(aContext, fnObj, 0, PRIVATE_TO_JSVAL(self.get())))
return NULL;
// make a strong reference to the library for GC-safety
if (!JS_SetReservedSlot(aContext, fnObj, 1, OBJECT_TO_JSVAL(aLibrary)))
return NULL;
// tell the library we exist, so it can delete our Function instance
// when it comes time to finalize. (JS functions don't have finalizers.)
if (!Library::AddFunction(aContext, aLibrary, self))
return NULL;
self.forget();
return fnObj;
}
static Function*
GetFunction(JSContext* cx, JSObject* obj)
{
jsval slot;
JS_GetReservedSlot(cx, obj, 0, &slot);
return static_cast<Function*>(JSVAL_TO_PRIVATE(slot));
}
JSBool
Function::Call(JSContext* cx, uintN argc, jsval* vp)
{
JSObject* callee = JSVAL_TO_OBJECT(JS_CALLEE(cx, vp));
jsval slot;
JS_GetReservedSlot(cx, callee, 1, &slot);
PRLibrary* library = Library::GetLibrary(cx, JSVAL_TO_OBJECT(slot));
if (!library) {
JS_ReportError(cx, "library is not open");
return JS_FALSE;
}
return GetFunction(cx, callee)->Execute(cx, argc, vp);
}
}
}
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