//
// Copyright (c) 2013 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// validationES.h: Validation functions for generic OpenGL ES entry point parameters

#ifndef LIBANGLE_VALIDATION_ES_H_
#define LIBANGLE_VALIDATION_ES_H_

#include "common/PackedEnums.h"
#include "common/mathutil.h"
#include "common/utilities.h"
#include "libANGLE/Context.h"
#include "libANGLE/ErrorStrings.h"
#include "libANGLE/Framebuffer.h"
#include "libANGLE/VertexArray.h"

#include <GLES2/gl2.h>
#include <GLES3/gl3.h>
#include <GLES3/gl31.h>

namespace egl
{
class Display;
class Image;
}  // namespace egl

namespace gl
{
class Context;
struct Format;
class Framebuffer;
struct LinkedUniform;
class Program;
class Shader;

void SetRobustLengthParam(GLsizei *length, GLsizei value);
bool IsETC2EACFormat(const GLenum format);
bool ValidTextureTarget(const Context *context, TextureType type);
bool ValidTexture2DTarget(const Context *context, TextureType type);
bool ValidTexture3DTarget(const Context *context, TextureType target);
bool ValidTextureExternalTarget(const Context *context, TextureType target);
bool ValidTexture2DDestinationTarget(const Context *context, TextureTarget target);
bool ValidTexture3DDestinationTarget(const Context *context, TextureType target);
bool ValidTexLevelDestinationTarget(const Context *context, TextureType type);
bool ValidFramebufferTarget(const Context *context, GLenum target);
bool ValidMipLevel(const Context *context, TextureType type, GLint level);
bool ValidImageSizeParameters(Context *context,
                              TextureType target,
                              GLint level,
                              GLsizei width,
                              GLsizei height,
                              GLsizei depth,
                              bool isSubImage);
bool ValidCompressedImageSize(const Context *context,
                              GLenum internalFormat,
                              GLint level,
                              GLsizei width,
                              GLsizei height);
bool ValidCompressedSubImageSize(const Context *context,
                                 GLenum internalFormat,
                                 GLint xoffset,
                                 GLint yoffset,
                                 GLsizei width,
                                 GLsizei height,
                                 size_t textureWidth,
                                 size_t textureHeight);
bool ValidImageDataSize(Context *context,
                        TextureType texType,
                        GLsizei width,
                        GLsizei height,
                        GLsizei depth,
                        GLenum format,
                        GLenum type,
                        const void *pixels,
                        GLsizei imageSize);

bool ValidQueryType(const Context *context, QueryType queryType);

bool ValidateWebGLVertexAttribPointer(Context *context,
                                      GLenum type,
                                      GLboolean normalized,
                                      GLsizei stride,
                                      const void *ptr,
                                      bool pureInteger);

// Returns valid program if id is a valid program name
// Errors INVALID_OPERATION if valid shader is given and returns NULL
// Errors INVALID_VALUE otherwise and returns NULL
Program *GetValidProgram(Context *context, GLuint id);

// Returns valid shader if id is a valid shader name
// Errors INVALID_OPERATION if valid program is given and returns NULL
// Errors INVALID_VALUE otherwise and returns NULL
Shader *GetValidShader(Context *context, GLuint id);

bool ValidateAttachmentTarget(Context *context, GLenum attachment);
bool ValidateRenderbufferStorageParametersBase(Context *context,
                                               GLenum target,
                                               GLsizei samples,
                                               GLenum internalformat,
                                               GLsizei width,
                                               GLsizei height);
bool ValidateFramebufferRenderbufferParameters(Context *context,
                                               GLenum target,
                                               GLenum attachment,
                                               GLenum renderbuffertarget,
                                               GLuint renderbuffer);

bool ValidateBlitFramebufferParameters(Context *context,
                                       GLint srcX0,
                                       GLint srcY0,
                                       GLint srcX1,
                                       GLint srcY1,
                                       GLint dstX0,
                                       GLint dstY0,
                                       GLint dstX1,
                                       GLint dstY1,
                                       GLbitfield mask,
                                       GLenum filter);

bool ValidateReadPixelsBase(Context *context,
                            GLint x,
                            GLint y,
                            GLsizei width,
                            GLsizei height,
                            GLenum format,
                            GLenum type,
                            GLsizei bufSize,
                            GLsizei *length,
                            GLsizei *columns,
                            GLsizei *rows,
                            void *pixels);
bool ValidateReadPixelsRobustANGLE(Context *context,
                                   GLint x,
                                   GLint y,
                                   GLsizei width,
                                   GLsizei height,
                                   GLenum format,
                                   GLenum type,
                                   GLsizei bufSize,
                                   GLsizei *length,
                                   GLsizei *columns,
                                   GLsizei *rows,
                                   void *pixels);
bool ValidateReadnPixelsEXT(Context *context,
                            GLint x,
                            GLint y,
                            GLsizei width,
                            GLsizei height,
                            GLenum format,
                            GLenum type,
                            GLsizei bufSize,
                            void *pixels);
bool ValidateReadnPixelsRobustANGLE(Context *context,
                                    GLint x,
                                    GLint y,
                                    GLsizei width,
                                    GLsizei height,
                                    GLenum format,
                                    GLenum type,
                                    GLsizei bufSize,
                                    GLsizei *length,
                                    GLsizei *columns,
                                    GLsizei *rows,
                                    void *data);

bool ValidateGenQueriesEXT(gl::Context *context, GLsizei n, GLuint *ids);
bool ValidateDeleteQueriesEXT(gl::Context *context, GLsizei n, const GLuint *ids);
bool ValidateIsQueryEXT(gl::Context *context, GLuint id);
bool ValidateBeginQueryBase(Context *context, QueryType target, GLuint id);
bool ValidateBeginQueryEXT(Context *context, QueryType target, GLuint id);
bool ValidateEndQueryBase(Context *context, QueryType target);
bool ValidateEndQueryEXT(Context *context, QueryType target);
bool ValidateQueryCounterEXT(Context *context, GLuint id, QueryType target);
bool ValidateGetQueryivBase(Context *context, QueryType target, GLenum pname, GLsizei *numParams);
bool ValidateGetQueryivEXT(Context *context, QueryType target, GLenum pname, GLint *params);
bool ValidateGetQueryivRobustANGLE(Context *context,
                                   QueryType target,
                                   GLenum pname,
                                   GLsizei bufSize,
                                   GLsizei *length,
                                   GLint *params);
bool ValidateGetQueryObjectValueBase(Context *context, GLuint id, GLenum pname, GLsizei *numParams);
bool ValidateGetQueryObjectivEXT(Context *context, GLuint id, GLenum pname, GLint *params);
bool ValidateGetQueryObjectivRobustANGLE(Context *context,
                                         GLuint id,
                                         GLenum pname,
                                         GLsizei bufSize,
                                         GLsizei *length,
                                         GLint *params);
bool ValidateGetQueryObjectuivEXT(Context *context, GLuint id, GLenum pname, GLuint *params);
bool ValidateGetQueryObjectuivRobustANGLE(Context *context,
                                          GLuint id,
                                          GLenum pname,
                                          GLsizei bufSize,
                                          GLsizei *length,
                                          GLuint *params);
bool ValidateGetQueryObjecti64vEXT(Context *context, GLuint id, GLenum pname, GLint64 *params);
bool ValidateGetQueryObjecti64vRobustANGLE(Context *context,
                                           GLuint id,
                                           GLenum pname,
                                           GLsizei bufSize,
                                           GLsizei *length,
                                           GLint64 *params);
bool ValidateGetQueryObjectui64vEXT(Context *context, GLuint id, GLenum pname, GLuint64 *params);
bool ValidateGetQueryObjectui64vRobustANGLE(Context *context,
                                            GLuint id,
                                            GLenum pname,
                                            GLsizei bufSize,
                                            GLsizei *length,
                                            GLuint64 *params);

bool ValidateUniformCommonBase(Context *context,
                               gl::Program *program,
                               GLint location,
                               GLsizei count,
                               const LinkedUniform **uniformOut);
bool ValidateUniform1ivValue(Context *context,
                             GLenum uniformType,
                             GLsizei count,
                             const GLint *value);

ANGLE_INLINE bool ValidateUniformValue(Context *context, GLenum valueType, GLenum uniformType)
{
    // Check that the value type is compatible with uniform type.
    // Do the cheaper test first, for a little extra speed.
    if (valueType != uniformType && VariableBoolVectorType(valueType) != uniformType)
    {
        context->validationError(GL_INVALID_OPERATION, err::kUniformSizeMismatch);
        return false;
    }
    return true;
}

bool ValidateUniformMatrixValue(Context *context, GLenum valueType, GLenum uniformType);
bool ValidateUniform(Context *context, GLenum uniformType, GLint location, GLsizei count);
bool ValidateUniformMatrix(Context *context,
                           GLenum matrixType,
                           GLint location,
                           GLsizei count,
                           GLboolean transpose);
bool ValidateGetBooleanvRobustANGLE(Context *context,
                                    GLenum pname,
                                    GLsizei bufSize,
                                    GLsizei *length,
                                    GLboolean *params);
bool ValidateGetFloatvRobustANGLE(Context *context,
                                  GLenum pname,
                                  GLsizei bufSize,
                                  GLsizei *length,
                                  GLfloat *params);
bool ValidateStateQuery(Context *context,
                        GLenum pname,
                        GLenum *nativeType,
                        unsigned int *numParams);
bool ValidateGetIntegervRobustANGLE(Context *context,
                                    GLenum pname,
                                    GLsizei bufSize,
                                    GLsizei *length,
                                    GLint *data);
bool ValidateGetInteger64vRobustANGLE(Context *context,
                                      GLenum pname,
                                      GLsizei bufSize,
                                      GLsizei *length,
                                      GLint64 *data);
bool ValidateRobustStateQuery(Context *context,
                              GLenum pname,
                              GLsizei bufSize,
                              GLenum *nativeType,
                              unsigned int *numParams);

bool ValidateCopyTexImageParametersBase(Context *context,
                                        TextureTarget target,
                                        GLint level,
                                        GLenum internalformat,
                                        bool isSubImage,
                                        GLint xoffset,
                                        GLint yoffset,
                                        GLint zoffset,
                                        GLint x,
                                        GLint y,
                                        GLsizei width,
                                        GLsizei height,
                                        GLint border,
                                        Format *textureFormatOut);

void RecordDrawModeError(Context *context, PrimitiveMode mode);
const char *ValidateDrawElementsStates(Context *context);

ANGLE_INLINE bool ValidateDrawBase(Context *context, PrimitiveMode mode)
{
    if (!context->getStateCache().isValidDrawMode(mode))
    {
        RecordDrawModeError(context, mode);
        return false;
    }

    intptr_t drawStatesError = context->getStateCache().getBasicDrawStatesError(context);
    if (drawStatesError)
    {
        const char *errorMessage = reinterpret_cast<const char *>(drawStatesError);

        // All errors from ValidateDrawStates should return INVALID_OPERATION except Framebuffer
        // Incomplete.
        GLenum errorCode =
            (errorMessage == err::kDrawFramebufferIncomplete ? GL_INVALID_FRAMEBUFFER_OPERATION
                                                             : GL_INVALID_OPERATION);
        context->validationError(errorCode, errorMessage);
        return false;
    }

    return true;
}

bool ValidateDrawArraysInstancedBase(Context *context,
                                     PrimitiveMode mode,
                                     GLint first,
                                     GLsizei count,
                                     GLsizei primcount);
bool ValidateDrawArraysInstancedANGLE(Context *context,
                                      PrimitiveMode mode,
                                      GLint first,
                                      GLsizei count,
                                      GLsizei primcount);

bool ValidateDrawElementsInstancedCommon(Context *context,
                                         PrimitiveMode mode,
                                         GLsizei count,
                                         DrawElementsType type,
                                         const void *indices,
                                         GLsizei primcount);
bool ValidateDrawElementsInstancedANGLE(Context *context,
                                        PrimitiveMode mode,
                                        GLsizei count,
                                        DrawElementsType type,
                                        const void *indices,
                                        GLsizei primcount);
bool ValidateDrawInstancedANGLE(Context *context);

bool ValidateFramebufferTextureBase(Context *context,
                                    GLenum target,
                                    GLenum attachment,
                                    GLuint texture,
                                    GLint level);

bool ValidateGetUniformBase(Context *context, GLuint program, GLint location);
bool ValidateGetnUniformfvEXT(Context *context,
                              GLuint program,
                              GLint location,
                              GLsizei bufSize,
                              GLfloat *params);
bool ValidateGetnUniformfvRobustANGLE(Context *context,
                                      GLuint program,
                                      GLint location,
                                      GLsizei bufSize,
                                      GLsizei *length,
                                      GLfloat *params);
bool ValidateGetnUniformivEXT(Context *context,
                              GLuint program,
                              GLint location,
                              GLsizei bufSize,
                              GLint *params);
bool ValidateGetnUniformivRobustANGLE(Context *context,
                                      GLuint program,
                                      GLint location,
                                      GLsizei bufSize,
                                      GLsizei *length,
                                      GLint *params);
bool ValidateGetnUniformuivRobustANGLE(Context *context,
                                       GLuint program,
                                       GLint location,
                                       GLsizei bufSize,
                                       GLsizei *length,
                                       GLuint *params);
bool ValidateGetUniformfvRobustANGLE(Context *context,
                                     GLuint program,
                                     GLint location,
                                     GLsizei bufSize,
                                     GLsizei *length,
                                     GLfloat *params);
bool ValidateGetUniformivRobustANGLE(Context *context,
                                     GLuint program,
                                     GLint location,
                                     GLsizei bufSize,
                                     GLsizei *length,
                                     GLint *params);
bool ValidateGetUniformuivRobustANGLE(Context *context,
                                      GLuint program,
                                      GLint location,
                                      GLsizei bufSize,
                                      GLsizei *length,
                                      GLuint *params);

bool ValidateDiscardFramebufferBase(Context *context,
                                    GLenum target,
                                    GLsizei numAttachments,
                                    const GLenum *attachments,
                                    bool defaultFramebuffer);

bool ValidateInsertEventMarkerEXT(Context *context, GLsizei length, const char *marker);
bool ValidatePushGroupMarkerEXT(Context *context, GLsizei length, const char *marker);

bool ValidateEGLImageTargetTexture2DOES(Context *context,
                                        gl::TextureType type,
                                        GLeglImageOES image);
bool ValidateEGLImageTargetRenderbufferStorageOES(Context *context,
                                                  GLenum target,
                                                  GLeglImageOES image);

bool ValidateBindVertexArrayBase(Context *context, GLuint array);

bool ValidateProgramBinaryBase(Context *context,
                               GLuint program,
                               GLenum binaryFormat,
                               const void *binary,
                               GLint length);
bool ValidateGetProgramBinaryBase(Context *context,
                                  GLuint program,
                                  GLsizei bufSize,
                                  GLsizei *length,
                                  GLenum *binaryFormat,
                                  void *binary);

bool ValidateDrawBuffersBase(Context *context, GLsizei n, const GLenum *bufs);

bool ValidateGetBufferPointervBase(Context *context,
                                   BufferBinding target,
                                   GLenum pname,
                                   GLsizei *length,
                                   void **params);
bool ValidateUnmapBufferBase(Context *context, BufferBinding target);
bool ValidateMapBufferRangeBase(Context *context,
                                BufferBinding target,
                                GLintptr offset,
                                GLsizeiptr length,
                                GLbitfield access);
bool ValidateFlushMappedBufferRangeBase(Context *context,
                                        BufferBinding target,
                                        GLintptr offset,
                                        GLsizeiptr length);

bool ValidateGenOrDelete(Context *context, GLint n);

bool ValidateRobustEntryPoint(Context *context, GLsizei bufSize);
bool ValidateRobustBufferSize(Context *context, GLsizei bufSize, GLsizei numParams);

bool ValidateGetFramebufferAttachmentParameterivBase(Context *context,
                                                     GLenum target,
                                                     GLenum attachment,
                                                     GLenum pname,
                                                     GLsizei *numParams);

bool ValidateGetBufferParameterBase(Context *context,
                                    BufferBinding target,
                                    GLenum pname,
                                    bool pointerVersion,
                                    GLsizei *numParams);

bool ValidateGetProgramivBase(Context *context, GLuint program, GLenum pname, GLsizei *numParams);

bool ValidateGetRenderbufferParameterivBase(Context *context,
                                            GLenum target,
                                            GLenum pname,
                                            GLsizei *length);

bool ValidateGetShaderivBase(Context *context, GLuint shader, GLenum pname, GLsizei *length);

bool ValidateGetTexParameterBase(Context *context,
                                 TextureType target,
                                 GLenum pname,
                                 GLsizei *length);

template <typename ParamType>
bool ValidateTexParameterBase(Context *context,
                              TextureType target,
                              GLenum pname,
                              GLsizei bufSize,
                              bool vectorParams,
                              const ParamType *params);

bool ValidateGetVertexAttribBase(Context *context,
                                 GLuint index,
                                 GLenum pname,
                                 GLsizei *length,
                                 bool pointer,
                                 bool pureIntegerEntryPoint);

bool ValidateVertexFormatBase(Context *context,
                              GLuint attribIndex,
                              GLint size,
                              GLenum type,
                              GLboolean pureInteger);

bool ValidateWebGLFramebufferAttachmentClearType(Context *context,
                                                 GLint drawbuffer,
                                                 const GLenum *validComponentTypes,
                                                 size_t validComponentTypeCount);

bool ValidateRobustCompressedTexImageBase(Context *context, GLsizei imageSize, GLsizei dataSize);

bool ValidateVertexAttribIndex(Context *context, GLuint index);

bool ValidateGetActiveUniformBlockivBase(Context *context,
                                         GLuint program,
                                         GLuint uniformBlockIndex,
                                         GLenum pname,
                                         GLsizei *length);

bool ValidateGetSamplerParameterBase(Context *context,
                                     GLuint sampler,
                                     GLenum pname,
                                     GLsizei *length);

template <typename ParamType>
bool ValidateSamplerParameterBase(Context *context,
                                  GLuint sampler,
                                  GLenum pname,
                                  GLsizei bufSize,
                                  bool vectorParams,
                                  ParamType *params);

bool ValidateGetInternalFormativBase(Context *context,
                                     GLenum target,
                                     GLenum internalformat,
                                     GLenum pname,
                                     GLsizei bufSize,
                                     GLsizei *numParams);

bool ValidateFramebufferNotMultisampled(Context *context, Framebuffer *framebuffer);

bool ValidateMultitextureUnit(Context *context, GLenum texture);

bool ValidateTransformFeedbackPrimitiveMode(const Context *context,
                                            PrimitiveMode transformFeedbackPrimitiveMode,
                                            PrimitiveMode renderPrimitiveMode);

// Common validation for 2D and 3D variants of TexStorage*Multisample.
bool ValidateTexStorageMultisample(Context *context,
                                   TextureType target,
                                   GLsizei samples,
                                   GLint internalFormat,
                                   GLsizei width,
                                   GLsizei height);

bool ValidateTexStorage2DMultisampleBase(Context *context,
                                         TextureType target,
                                         GLsizei samples,
                                         GLint internalFormat,
                                         GLsizei width,
                                         GLsizei height);

bool ValidateGetTexLevelParameterBase(Context *context,
                                      TextureTarget target,
                                      GLint level,
                                      GLenum pname,
                                      GLsizei *length);

bool ValidateMapBufferBase(Context *context, BufferBinding target);
bool ValidateIndexedStateQuery(Context *context, GLenum pname, GLuint index, GLsizei *length);
bool ValidateES3TexImage2DParameters(Context *context,
                                     TextureTarget target,
                                     GLint level,
                                     GLenum internalformat,
                                     bool isCompressed,
                                     bool isSubImage,
                                     GLint xoffset,
                                     GLint yoffset,
                                     GLint zoffset,
                                     GLsizei width,
                                     GLsizei height,
                                     GLsizei depth,
                                     GLint border,
                                     GLenum format,
                                     GLenum type,
                                     GLsizei imageSize,
                                     const void *pixels);
bool ValidateES3CopyTexImage2DParameters(Context *context,
                                         TextureTarget target,
                                         GLint level,
                                         GLenum internalformat,
                                         bool isSubImage,
                                         GLint xoffset,
                                         GLint yoffset,
                                         GLint zoffset,
                                         GLint x,
                                         GLint y,
                                         GLsizei width,
                                         GLsizei height,
                                         GLint border);
bool ValidateES3TexStorage2DParameters(Context *context,
                                       TextureType target,
                                       GLsizei levels,
                                       GLenum internalformat,
                                       GLsizei width,
                                       GLsizei height,
                                       GLsizei depth);
bool ValidateES3TexStorage3DParameters(Context *context,
                                       TextureType target,
                                       GLsizei levels,
                                       GLenum internalformat,
                                       GLsizei width,
                                       GLsizei height,
                                       GLsizei depth);

bool ValidateGetMultisamplefvBase(Context *context, GLenum pname, GLuint index, GLfloat *val);
bool ValidateSampleMaskiBase(Context *context, GLuint maskNumber, GLbitfield mask);

// Utility macro for handling implementation methods inside Validation.
#define ANGLE_HANDLE_VALIDATION_ERR(X) \
    (void)(X);                         \
    return false;
#define ANGLE_VALIDATION_TRY(EXPR) ANGLE_TRY_TEMPLATE(EXPR, ANGLE_HANDLE_VALIDATION_ERR);

// We should check with Khronos if returning INVALID_FRAMEBUFFER_OPERATION is OK when querying
// implementation format info for incomplete framebuffers. It seems like these queries are
// incongruent with the other errors.
// Inlined for speed.
template <GLenum ErrorCode = GL_INVALID_FRAMEBUFFER_OPERATION>
ANGLE_INLINE bool ValidateFramebufferComplete(Context *context, Framebuffer *framebuffer)
{
    if (!framebuffer->isComplete(context))
    {
        context->validationError(ErrorCode, err::kFramebufferIncomplete);
        return false;
    }

    return true;
}

const char *ValidateDrawStates(Context *context);

void RecordDrawAttribsError(Context *context);

ANGLE_INLINE bool ValidateDrawAttribs(Context *context, int64_t maxVertex)
{
    if (maxVertex > context->getStateCache().getNonInstancedVertexElementLimit())
    {
        RecordDrawAttribsError(context);
        return false;
    }

    return true;
}

ANGLE_INLINE bool ValidateDrawArraysAttribs(Context *context, GLint first, GLsizei count)
{
    // Check the computation of maxVertex doesn't overflow.
    // - first < 0 has been checked as an error condition.
    // - if count <= 0, skip validating no-op draw calls.
    // From this we know maxVertex will be positive, and only need to check if it overflows GLint.
    ASSERT(first >= 0);
    ASSERT(count > 0);
    int64_t maxVertex = static_cast<int64_t>(first) + static_cast<int64_t>(count) - 1;
    if (maxVertex > static_cast<int64_t>(std::numeric_limits<GLint>::max()))
    {
        context->validationError(GL_INVALID_OPERATION, err::kIntegerOverflow);
        return false;
    }

    return ValidateDrawAttribs(context, maxVertex);
}

ANGLE_INLINE bool ValidateDrawInstancedAttribs(Context *context, GLint primcount)
{
    if ((primcount - 1) > context->getStateCache().getInstancedVertexElementLimit())
    {
        RecordDrawAttribsError(context);
        return false;
    }

    return true;
}

ANGLE_INLINE bool ValidateDrawArraysCommon(Context *context,
                                           PrimitiveMode mode,
                                           GLint first,
                                           GLsizei count,
                                           GLsizei primcount)
{
    if (first < 0)
    {
        context->validationError(GL_INVALID_VALUE, err::kNegativeStart);
        return false;
    }

    if (count <= 0)
    {
        if (count < 0)
        {
            context->validationError(GL_INVALID_VALUE, err::kNegativeCount);
            return false;
        }

        // Early exit.
        return ValidateDrawBase(context, mode);
    }

    if (!ValidateDrawBase(context, mode))
    {
        return false;
    }

    if (context->getStateCache().isTransformFeedbackActiveUnpaused())
    {
        const State &state                      = context->getState();
        TransformFeedback *curTransformFeedback = state.getCurrentTransformFeedback();
        if (!curTransformFeedback->checkBufferSpaceForDraw(count, primcount))
        {
            context->validationError(GL_INVALID_OPERATION, err::kTransformFeedbackBufferTooSmall);
            return false;
        }
    }

    return ValidateDrawArraysAttribs(context, first, count);
}

ANGLE_INLINE bool ValidateDrawElementsBase(Context *context,
                                           PrimitiveMode mode,
                                           DrawElementsType type)
{
    if (!context->getStateCache().isValidDrawElementsType(type))
    {
        if (type == DrawElementsType::UnsignedInt)
        {
            context->validationError(GL_INVALID_ENUM, err::kTypeNotUnsignedShortByte);
            return false;
        }

        ASSERT(type == DrawElementsType::InvalidEnum);
        context->validationError(GL_INVALID_ENUM, err::kEnumNotSupported);
        return false;
    }

    intptr_t drawElementsError = context->getStateCache().getBasicDrawElementsError(context);
    if (drawElementsError)
    {
        // All errors from ValidateDrawElementsStates return INVALID_OPERATION.
        const char *errorMessage = reinterpret_cast<const char *>(drawElementsError);
        context->validationError(GL_INVALID_OPERATION, errorMessage);
        return false;
    }

    // Note that we are missing overflow checks for active transform feedback buffers.
    return true;
}

ANGLE_INLINE bool ValidateDrawElementsCommon(Context *context,
                                             PrimitiveMode mode,
                                             GLsizei count,
                                             DrawElementsType type,
                                             const void *indices,
                                             GLsizei primcount)
{
    if (!ValidateDrawElementsBase(context, mode, type))
    {
        return false;
    }

    ASSERT(isPow2(GetDrawElementsTypeSize(type)) && GetDrawElementsTypeSize(type) > 0);

    if (context->getExtensions().webglCompatibility)
    {
        GLuint typeBytes = GetDrawElementsTypeSize(type);

        if ((reinterpret_cast<uintptr_t>(indices) & static_cast<uintptr_t>(typeBytes - 1)) != 0)
        {
            // [WebGL 1.0] Section 6.4 Buffer Offset and Stride Requirements
            // The offset arguments to drawElements and [...], must be a multiple of the size of the
            // data type passed to the call, or an INVALID_OPERATION error is generated.
            context->validationError(GL_INVALID_OPERATION, err::kOffsetMustBeMultipleOfType);
            return false;
        }

        // [WebGL 1.0] Section 6.4 Buffer Offset and Stride Requirements
        // In addition the offset argument to drawElements must be non-negative or an INVALID_VALUE
        // error is generated.
        if (reinterpret_cast<intptr_t>(indices) < 0)
        {
            context->validationError(GL_INVALID_VALUE, err::kNegativeOffset);
            return false;
        }
    }

    if (count <= 0)
    {
        if (count < 0)
        {
            context->validationError(GL_INVALID_VALUE, err::kNegativeCount);
            return false;
        }

        // Early exit.
        return ValidateDrawBase(context, mode);
    }

    if (!ValidateDrawBase(context, mode))
    {
        return false;
    }

    const State &state         = context->getState();
    const VertexArray *vao     = state.getVertexArray();
    Buffer *elementArrayBuffer = vao->getElementArrayBuffer();

    if (!elementArrayBuffer)
    {
        if (!indices)
        {
            // This is an application error that would normally result in a crash, but we catch
            // it and return an error
            context->validationError(GL_INVALID_OPERATION, err::kElementArrayNoBufferOrPointer);
            return false;
        }
    }
    else
    {
        // The max possible type size is 8 and count is on 32 bits so doing the multiplication
        // in a 64 bit integer is safe. Also we are guaranteed that here count > 0.
        static_assert(std::is_same<int, GLsizei>::value, "GLsizei isn't the expected type");
        constexpr uint64_t kMaxTypeSize = 8;
        constexpr uint64_t kIntMax      = std::numeric_limits<int>::max();
        constexpr uint64_t kUint64Max   = std::numeric_limits<uint64_t>::max();
        static_assert(kIntMax < kUint64Max / kMaxTypeSize, "");

        uint64_t elementCount = static_cast<uint64_t>(count);
        ASSERT(elementCount > 0 && GetDrawElementsTypeSize(type) <= kMaxTypeSize);

        // Doing the multiplication here is overflow-safe
        uint64_t elementDataSizeNoOffset = elementCount << GetDrawElementsTypeShift(type);

        // The offset can be any value, check for overflows
        uint64_t offset = static_cast<uint64_t>(reinterpret_cast<uintptr_t>(indices));
        uint64_t elementDataSizeWithOffset = elementDataSizeNoOffset + offset;
        if (elementDataSizeWithOffset < elementDataSizeNoOffset)
        {
            context->validationError(GL_INVALID_OPERATION, err::kIntegerOverflow);
            return false;
        }

        if (elementDataSizeWithOffset > static_cast<uint64_t>(elementArrayBuffer->getSize()))
        {
            context->validationError(GL_INVALID_OPERATION, err::kInsufficientBufferSize);
            return false;
        }
    }

    if (!context->getExtensions().robustBufferAccessBehavior && primcount > 0)
    {
        // Use the parameter buffer to retrieve and cache the index range.
        IndexRange indexRange{IndexRange::Undefined()};
        ANGLE_VALIDATION_TRY(vao->getIndexRange(context, type, count, indices, &indexRange));

        // If we use an index greater than our maximum supported index range, return an error.
        // The ES3 spec does not specify behaviour here, it is undefined, but ANGLE should
        // always return an error if possible here.
        if (static_cast<GLuint64>(indexRange.end) >= context->getCaps().maxElementIndex)
        {
            context->validationError(GL_INVALID_OPERATION, err::kExceedsMaxElement);
            return false;
        }

        if (!ValidateDrawAttribs(context, static_cast<GLint>(indexRange.end)))
        {
            return false;
        }

        // No op if there are no real indices in the index data (all are primitive restart).
        return (indexRange.vertexIndexCount > 0);
    }

    return true;
}
}  // namespace gl

#endif  // LIBANGLE_VALIDATION_ES_H_
