gecko-dev/dom/canvas/WebGLContextValidate.cpp

601 строка
20 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "WebGLContext.h"
#include <algorithm>
#include "GLSLANG/ShaderLang.h"
#include "CanvasUtils.h"
#include "GLContext.h"
#include "jsfriendapi.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/Preferences.h"
#include "mozilla/StaticPrefs_webgl.h"
#include "nsPrintfCString.h"
#include "WebGLBuffer.h"
#include "WebGLContextUtils.h"
#include "WebGLFramebuffer.h"
#include "WebGLProgram.h"
#include "WebGLRenderbuffer.h"
#include "WebGLSampler.h"
#include "WebGLShader.h"
#include "WebGLTexture.h"
#include "WebGLValidateStrings.h"
#include "WebGLVertexArray.h"
#if defined(MOZ_WIDGET_COCOA)
# include "nsCocoaFeatures.h"
#endif
////////////////////
// Minimum value constants defined in GLES 2.0.25 $6.2 "State Tables":
const uint32_t kMinMaxVertexAttribs = 8; // Page 164
const uint32_t kMinMaxVertexUniformVectors = 128; // Page 164
const uint32_t kMinMaxFragmentUniformVectors = 16; // Page 164
const uint32_t kMinMaxVaryingVectors = 8; // Page 164
const uint32_t kMinMaxVertexTextureImageUnits = 0; // Page 164
const uint32_t kMinMaxFragmentTextureImageUnits = 8; // Page 164
const uint32_t kMinMaxCombinedTextureImageUnits = 8; // Page 164
const uint32_t kMinMaxDrawBuffers = 4;
// These few deviate from the spec: (The minimum values in the spec are
// ridiculously low)
const uint32_t kMinMaxTextureSize = 1024; // ES2 spec says `64` (p162)
const uint32_t kMinMaxCubeMapTextureSize = 512; // ES2 spec says `16` (p162)
const uint32_t kMinMaxRenderbufferSize = 1024; // ES2 spec says `1` (p164)
// Minimum value constants defined in GLES 3.0.4 $6.2 "State Tables":
const uint32_t kMinMax3DTextureSize = 256;
const uint32_t kMinMaxArrayTextureLayers = 256;
////////////////////
// "Common" but usable values to avoid WebGL fingerprinting:
const uint32_t kCommonMaxTextureSize = 2048;
const uint32_t kCommonMaxCubeMapTextureSize = 2048;
const uint32_t kCommonMaxRenderbufferSize = 2048;
const uint32_t kCommonMaxVertexTextureImageUnits = 8;
const uint32_t kCommonMaxFragmentTextureImageUnits = 8;
const uint32_t kCommonMaxCombinedTextureImageUnits = 16;
const uint32_t kCommonMaxVertexAttribs = 16;
const uint32_t kCommonMaxVertexUniformVectors = 256;
const uint32_t kCommonMaxFragmentUniformVectors = 224;
const uint32_t kCommonMaxVaryingVectors = 8;
const uint32_t kCommonMaxViewportDims = 4096;
// The following ranges came from a 2013 Moto E and an old macbook.
const float kCommonAliasedPointSizeRangeMin = 1;
const float kCommonAliasedPointSizeRangeMax = 63;
const float kCommonAliasedLineWidthRangeMin = 1;
const float kCommonAliasedLineWidthRangeMax = 1;
template <class T>
static bool RestrictCap(T* const cap, const T restrictedVal) {
if (*cap < restrictedVal) {
return false; // already too low!
}
*cap = restrictedVal;
return true;
}
////////////////////
namespace mozilla {
bool WebGLContext::ValidateBlendEquationEnum(GLenum mode, const char* info) {
switch (mode) {
case LOCAL_GL_FUNC_ADD:
case LOCAL_GL_FUNC_SUBTRACT:
case LOCAL_GL_FUNC_REVERSE_SUBTRACT:
return true;
case LOCAL_GL_MIN:
case LOCAL_GL_MAX:
if (IsWebGL2() ||
IsExtensionEnabled(WebGLExtensionID::EXT_blend_minmax)) {
return true;
}
break;
default:
break;
}
ErrorInvalidEnumInfo(info, mode);
return false;
}
bool WebGLContext::ValidateBlendFuncEnumsCompatibility(GLenum sfactor,
GLenum dfactor,
const char* info) {
bool sfactorIsConstantColor = sfactor == LOCAL_GL_CONSTANT_COLOR ||
sfactor == LOCAL_GL_ONE_MINUS_CONSTANT_COLOR;
bool sfactorIsConstantAlpha = sfactor == LOCAL_GL_CONSTANT_ALPHA ||
sfactor == LOCAL_GL_ONE_MINUS_CONSTANT_ALPHA;
bool dfactorIsConstantColor = dfactor == LOCAL_GL_CONSTANT_COLOR ||
dfactor == LOCAL_GL_ONE_MINUS_CONSTANT_COLOR;
bool dfactorIsConstantAlpha = dfactor == LOCAL_GL_CONSTANT_ALPHA ||
dfactor == LOCAL_GL_ONE_MINUS_CONSTANT_ALPHA;
if ((sfactorIsConstantColor && dfactorIsConstantAlpha) ||
(dfactorIsConstantColor && sfactorIsConstantAlpha)) {
ErrorInvalidOperation(
"%s are mutually incompatible, see section 6.8 in"
" the WebGL 1.0 spec",
info);
return false;
}
return true;
}
bool WebGLContext::ValidateStencilOpEnum(GLenum action, const char* info) {
switch (action) {
case LOCAL_GL_KEEP:
case LOCAL_GL_ZERO:
case LOCAL_GL_REPLACE:
case LOCAL_GL_INCR:
case LOCAL_GL_INCR_WRAP:
case LOCAL_GL_DECR:
case LOCAL_GL_DECR_WRAP:
case LOCAL_GL_INVERT:
return true;
default:
ErrorInvalidEnumInfo(info, action);
return false;
}
}
bool WebGLContext::ValidateFaceEnum(const GLenum face) {
switch (face) {
case LOCAL_GL_FRONT:
case LOCAL_GL_BACK:
case LOCAL_GL_FRONT_AND_BACK:
return true;
default:
ErrorInvalidEnumInfo("face", face);
return false;
}
}
bool WebGLContext::ValidateAttribArraySetter(uint32_t setterElemSize,
uint32_t arrayLength) {
if (IsContextLost()) return false;
if (arrayLength < setterElemSize) {
ErrorInvalidValue("Array must have >= %d elements.", setterElemSize);
return false;
}
return true;
}
// ---------------------
static webgl::Limits MakeLimits(const WebGLContext& webgl) {
webgl::Limits limits;
gl::GLContext& gl = *webgl.GL();
// -
for (const auto i : IntegerRange(UnderlyingValue(WebGLExtensionID::Max))) {
const auto ext = WebGLExtensionID(i);
limits.supportedExtensions[ext] = webgl.IsExtensionSupported(ext);
}
// -
// WebGL 1
// Note: GL_MAX_TEXTURE_UNITS is fixed at 4 for most desktop hardware,
// even though the hardware supports much more. The
// GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS value is the accurate value.
gl.GetUIntegerv(LOCAL_GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS,
&limits.maxTexUnits);
gl.GetUIntegerv(LOCAL_GL_MAX_TEXTURE_SIZE, &limits.maxTex2dSize);
gl.GetUIntegerv(LOCAL_GL_MAX_CUBE_MAP_TEXTURE_SIZE, &limits.maxTexCubeSize);
gl.GetUIntegerv(LOCAL_GL_MAX_VERTEX_ATTRIBS, &limits.maxVertexAttribs);
auto dims = std::array<uint32_t, 2>{};
gl.GetUIntegerv(LOCAL_GL_MAX_VIEWPORT_DIMS, dims.data());
limits.maxViewportDim = std::min(dims[0], dims[1]);
if (!gl.IsCoreProfile()) {
gl.fGetFloatv(LOCAL_GL_ALIASED_LINE_WIDTH_RANGE,
limits.lineWidthRange.data());
}
{
const GLenum driverPName = gl.IsCoreProfile()
? LOCAL_GL_POINT_SIZE_RANGE
: LOCAL_GL_ALIASED_POINT_SIZE_RANGE;
gl.fGetFloatv(driverPName, limits.pointSizeRange.data());
}
if (webgl.IsWebGL2()) {
gl.GetUIntegerv(LOCAL_GL_MAX_ARRAY_TEXTURE_LAYERS,
&limits.maxTexArrayLayers);
gl.GetUIntegerv(LOCAL_GL_MAX_3D_TEXTURE_SIZE, &limits.maxTex3dSize);
gl.GetUIntegerv(LOCAL_GL_MAX_UNIFORM_BUFFER_BINDINGS,
&limits.maxUniformBufferBindings);
gl.GetUIntegerv(LOCAL_GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT,
&limits.uniformBufferOffsetAlignment);
}
if (limits.supportedExtensions
[WebGLExtensionID::WEBGL_compressed_texture_astc]) {
limits.astcHdr = gl.IsExtensionSupported(
gl::GLContext::KHR_texture_compression_astc_hdr);
}
if (webgl.IsWebGL2() ||
limits.supportedExtensions[WebGLExtensionID::WEBGL_draw_buffers]) {
gl.GetUIntegerv(LOCAL_GL_MAX_DRAW_BUFFERS, &limits.maxColorDrawBuffers);
}
if (limits.supportedExtensions[WebGLExtensionID::EXT_disjoint_timer_query]) {
gl.fGetQueryiv(LOCAL_GL_TIME_ELAPSED_EXT, LOCAL_GL_QUERY_COUNTER_BITS,
(int32_t*)&limits.queryCounterBitsTimeElapsed);
gl.fGetQueryiv(LOCAL_GL_TIMESTAMP_EXT, LOCAL_GL_QUERY_COUNTER_BITS,
(int32_t*)&limits.queryCounterBitsTimestamp);
}
if (limits.supportedExtensions[WebGLExtensionID::OVR_multiview2]) {
gl.GetUIntegerv(LOCAL_GL_MAX_VIEWS_OVR, &limits.maxMultiviewLayers);
}
return limits;
}
bool WebGLContext::InitAndValidateGL(FailureReason* const out_failReason) {
MOZ_RELEASE_ASSERT(gl, "GFX: GL not initialized");
// Unconditionally create a new format usage authority. This is
// important when restoring contexts and extensions need to add
// formats back into the authority.
mFormatUsage = CreateFormatUsage(gl);
if (!mFormatUsage) {
*out_failReason = {"FEATURE_FAILURE_WEBGL_FORMAT",
"Failed to create mFormatUsage."};
return false;
}
GLenum error = gl->fGetError();
if (error != LOCAL_GL_NO_ERROR) {
const nsPrintfCString reason(
"GL error 0x%x occurred during OpenGL context"
" initialization, before WebGL initialization!",
error);
*out_failReason = {"FEATURE_FAILURE_WEBGL_GLERR_1", reason};
return false;
}
mLoseContextOnMemoryPressure =
StaticPrefs::webgl_lose_context_on_memory_pressure();
mCanLoseContextInForeground =
StaticPrefs::webgl_can_lose_context_in_foreground();
/*
// Technically, we should be setting mStencil[...] values to
// `allOnes`, but either ANGLE breaks or the SGX540s on Try break.
GLuint stencilBits = 0;
gl->GetUIntegerv(LOCAL_GL_STENCIL_BITS, &stencilBits);
GLuint allOnes = ~(UINT32_MAX << stencilBits);
mStencilValueMaskFront = allOnes;
mStencilValueMaskBack = allOnes;
mStencilWriteMaskFront = allOnes;
mStencilWriteMaskBack = allOnes;
*/
gl->GetUIntegerv(LOCAL_GL_STENCIL_VALUE_MASK, &mStencilValueMaskFront);
gl->GetUIntegerv(LOCAL_GL_STENCIL_BACK_VALUE_MASK, &mStencilValueMaskBack);
gl->GetUIntegerv(LOCAL_GL_STENCIL_WRITEMASK, &mStencilWriteMaskFront);
gl->GetUIntegerv(LOCAL_GL_STENCIL_BACK_WRITEMASK, &mStencilWriteMaskBack);
AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_VALUE_MASK,
mStencilValueMaskFront);
AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_VALUE_MASK,
mStencilValueMaskBack);
AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_WRITEMASK,
mStencilWriteMaskFront);
AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_WRITEMASK,
mStencilWriteMaskBack);
// Bindings, etc.
mBound2DTextures.Clear();
mBoundCubeMapTextures.Clear();
mBound3DTextures.Clear();
mBound2DArrayTextures.Clear();
mBoundSamplers.Clear();
mBoundArrayBuffer = nullptr;
mCurrentProgram = nullptr;
mBoundDrawFramebuffer = nullptr;
mBoundReadFramebuffer = nullptr;
// -----------------------
auto limits = MakeLimits(*this);
// -
if (limits.maxVertexAttribs < 8) {
const nsPrintfCString reason("GL_MAX_VERTEX_ATTRIBS: %d is < 8!",
limits.maxVertexAttribs);
*out_failReason = {"FEATURE_FAILURE_WEBGL_V_ATRB", reason};
return false;
}
if (limits.maxTexUnits < 8) {
const nsPrintfCString reason(
"GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS: %u is < 8!", limits.maxTexUnits);
*out_failReason = {"FEATURE_FAILURE_WEBGL_T_UNIT", reason};
return false;
}
mBound2DTextures.SetLength(limits.maxTexUnits);
mBoundCubeMapTextures.SetLength(limits.maxTexUnits);
mBound3DTextures.SetLength(limits.maxTexUnits);
mBound2DArrayTextures.SetLength(limits.maxTexUnits);
mBoundSamplers.SetLength(limits.maxTexUnits);
////////////////
gl->GetUIntegerv(LOCAL_GL_MAX_RENDERBUFFER_SIZE, &mGLMaxRenderbufferSize);
gl->GetUIntegerv(LOCAL_GL_MAX_TEXTURE_IMAGE_UNITS,
&mGLMaxFragmentTextureImageUnits);
gl->GetUIntegerv(LOCAL_GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS,
&mGLMaxVertexTextureImageUnits);
////////////////
if (gl->IsGLES()) {
mGLMaxFragmentUniformVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_FRAGMENT_UNIFORM_VECTORS);
mGLMaxVertexUniformVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VERTEX_UNIFORM_VECTORS);
if (gl->Version() >= 300) {
mGLMaxVertexOutputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VERTEX_OUTPUT_COMPONENTS) / 4;
mGLMaxFragmentInputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_FRAGMENT_INPUT_COMPONENTS) / 4;
} else {
mGLMaxFragmentInputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VARYING_VECTORS);
mGLMaxVertexOutputVectors = mGLMaxFragmentInputVectors;
}
} else {
mGLMaxFragmentUniformVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_FRAGMENT_UNIFORM_COMPONENTS) / 4;
mGLMaxVertexUniformVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VERTEX_UNIFORM_COMPONENTS) / 4;
if (gl->Version() >= 320) {
mGLMaxVertexOutputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VERTEX_OUTPUT_COMPONENTS) / 4;
mGLMaxFragmentInputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_FRAGMENT_INPUT_COMPONENTS) / 4;
} else {
// Same enum val as GL2's GL_MAX_VARYING_FLOATS.
mGLMaxFragmentInputVectors =
gl->GetIntAs<uint32_t>(LOCAL_GL_MAX_VARYING_COMPONENTS) / 4;
mGLMaxVertexOutputVectors = mGLMaxFragmentInputVectors;
}
}
////////////////
if (StaticPrefs::webgl_min_capability_mode()) {
bool ok = true;
ok &= RestrictCap(&mGLMaxVertexTextureImageUnits,
kMinMaxVertexTextureImageUnits);
ok &= RestrictCap(&mGLMaxFragmentTextureImageUnits,
kMinMaxFragmentTextureImageUnits);
ok &= RestrictCap(&limits.maxTexUnits, kMinMaxCombinedTextureImageUnits);
ok &= RestrictCap(&limits.maxVertexAttribs, kMinMaxVertexAttribs);
ok &= RestrictCap(&mGLMaxVertexUniformVectors, kMinMaxVertexUniformVectors);
ok &= RestrictCap(&mGLMaxFragmentUniformVectors,
kMinMaxFragmentUniformVectors);
ok &= RestrictCap(&mGLMaxVertexOutputVectors, kMinMaxVaryingVectors);
ok &= RestrictCap(&mGLMaxFragmentInputVectors, kMinMaxVaryingVectors);
ok &= RestrictCap(&limits.maxColorDrawBuffers, kMinMaxDrawBuffers);
ok &= RestrictCap(&limits.maxTex2dSize, kMinMaxTextureSize);
ok &= RestrictCap(&limits.maxTexCubeSize, kMinMaxCubeMapTextureSize);
ok &= RestrictCap(&limits.maxTex3dSize, kMinMax3DTextureSize);
ok &= RestrictCap(&limits.maxTexArrayLayers, kMinMaxArrayTextureLayers);
ok &= RestrictCap(&mGLMaxRenderbufferSize, kMinMaxRenderbufferSize);
if (!ok) {
GenerateWarning("Unable to restrict WebGL limits to minimums.");
return false;
}
mDisableFragHighP = true;
} else if (mResistFingerprinting) {
bool ok = true;
ok &= RestrictCap(&limits.maxTex2dSize, kCommonMaxTextureSize);
ok &= RestrictCap(&limits.maxTexCubeSize, kCommonMaxCubeMapTextureSize);
ok &= RestrictCap(&mGLMaxRenderbufferSize, kCommonMaxRenderbufferSize);
ok &= RestrictCap(&mGLMaxVertexTextureImageUnits,
kCommonMaxVertexTextureImageUnits);
ok &= RestrictCap(&mGLMaxFragmentTextureImageUnits,
kCommonMaxFragmentTextureImageUnits);
ok &= RestrictCap(&limits.maxTexUnits, kCommonMaxCombinedTextureImageUnits);
ok &= RestrictCap(&limits.maxVertexAttribs, kCommonMaxVertexAttribs);
ok &= RestrictCap(&mGLMaxVertexUniformVectors,
kCommonMaxVertexUniformVectors);
ok &= RestrictCap(&mGLMaxFragmentUniformVectors,
kCommonMaxFragmentUniformVectors);
ok &= RestrictCap(&mGLMaxVertexOutputVectors, kCommonMaxVaryingVectors);
ok &= RestrictCap(&mGLMaxFragmentInputVectors, kCommonMaxVaryingVectors);
if (limits.lineWidthRange[0] <= kCommonAliasedLineWidthRangeMin) {
limits.lineWidthRange[0] = kCommonAliasedLineWidthRangeMin;
} else {
ok = false;
}
if (limits.pointSizeRange[0] <= kCommonAliasedPointSizeRangeMin) {
limits.pointSizeRange[0] = kCommonAliasedPointSizeRangeMin;
} else {
ok = false;
}
ok &=
RestrictCap(&limits.lineWidthRange[1], kCommonAliasedLineWidthRangeMax);
ok &=
RestrictCap(&limits.pointSizeRange[1], kCommonAliasedPointSizeRangeMax);
ok &= RestrictCap(&limits.maxViewportDim, kCommonMaxViewportDims);
if (!ok) {
GenerateWarning(
"Unable to restrict WebGL limits in order to resist fingerprinting");
return false;
}
}
mLimits = Some(limits);
////////////////
if (gl->IsCompatibilityProfile()) {
gl->fEnable(LOCAL_GL_POINT_SPRITE);
}
if (!gl->IsGLES()) {
gl->fEnable(LOCAL_GL_PROGRAM_POINT_SIZE);
}
#ifdef XP_MACOSX
if (gl->WorkAroundDriverBugs() && gl->Vendor() == gl::GLVendor::ATI &&
!nsCocoaFeatures::IsAtLeastVersion(10, 9)) {
// The Mac ATI driver, in all known OSX version up to and including
// 10.8, renders points sprites upside-down. (Apple bug 11778921)
gl->fPointParameterf(LOCAL_GL_POINT_SPRITE_COORD_ORIGIN,
LOCAL_GL_LOWER_LEFT);
}
#endif
if (gl->IsSupported(gl::GLFeature::seamless_cube_map_opt_in)) {
gl->fEnable(LOCAL_GL_TEXTURE_CUBE_MAP_SEAMLESS);
}
// initialize shader translator
if (!sh::Initialize()) {
*out_failReason = {"FEATURE_FAILURE_WEBGL_GLSL",
"GLSL translator initialization failed!"};
return false;
}
// Mesa can only be detected with the GL_VERSION string, of the form
// "2.1 Mesa 7.11.0"
const char* versionStr = (const char*)(gl->fGetString(LOCAL_GL_VERSION));
mIsMesa = strstr(versionStr, "Mesa");
// Notice that the point of calling fGetError here is not only to check for
// errors, but also to reset the error flags so that a subsequent WebGL
// getError call will give the correct result.
error = gl->fGetError();
if (error != LOCAL_GL_NO_ERROR) {
const nsPrintfCString reason(
"GL error 0x%x occurred during WebGL context"
" initialization!",
error);
*out_failReason = {"FEATURE_FAILURE_WEBGL_GLERR_2", reason};
return false;
}
if (IsWebGL2() && !InitWebGL2(out_failReason)) {
// Todo: Bug 898404: Only allow WebGL2 on GL>=3.0 on desktop GL.
return false;
}
// OpenGL core profiles remove the default VAO object from version
// 4.0.0. We create a default VAO for all core profiles,
// regardless of version.
//
// GL Spec 4.0.0:
// (https://www.opengl.org/registry/doc/glspec40.core.20100311.pdf)
// in Section E.2.2 "Removed Features", pg 397: "[...] The default
// vertex array object (the name zero) is also deprecated. [...]"
mDefaultVertexArray = WebGLVertexArray::Create(this);
mDefaultVertexArray->BindVertexArray();
mPrimRestartTypeBytes = 0;
mGenericVertexAttribTypes.assign(limits.maxVertexAttribs,
webgl::AttribBaseType::Float);
mGenericVertexAttribTypeInvalidator.InvalidateCaches();
static const float kDefaultGenericVertexAttribData[4] = {0, 0, 0, 1};
memcpy(mGenericVertexAttrib0Data, kDefaultGenericVertexAttribData,
sizeof(mGenericVertexAttrib0Data));
mFakeVertexAttrib0BufferObject = 0;
mNeedsIndexValidation =
!gl->IsSupported(gl::GLFeature::robust_buffer_access_behavior);
switch (StaticPrefs::webgl_force_index_validation()) {
case -1:
mNeedsIndexValidation = false;
break;
case 1:
mNeedsIndexValidation = true;
break;
default:
MOZ_ASSERT(StaticPrefs::webgl_force_index_validation() == 0);
break;
}
for (auto& cur : mExtensions) {
cur = {};
}
return true;
}
bool WebGLContext::ValidateFramebufferTarget(GLenum target) const {
bool isValid = true;
switch (target) {
case LOCAL_GL_FRAMEBUFFER:
break;
case LOCAL_GL_DRAW_FRAMEBUFFER:
case LOCAL_GL_READ_FRAMEBUFFER:
isValid = IsWebGL2();
break;
default:
isValid = false;
break;
}
if (MOZ_LIKELY(isValid)) {
return true;
}
ErrorInvalidEnumArg("target", target);
return false;
}
} // namespace mozilla