Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/gl_gl_api_implementation.cc

Index: ui/gl/gl_gl_api_implementation.cc
diff --git a/ui/gl/gl_gl_api_implementation.cc b/ui/gl/gl_gl_api_implementation.cc
index 265bd31f2bc2b86b83c0a4bd79bc1ceaf372cf25..cc4453ea910464274308768dfb8a9dcc9e77dc71 100644
--- a/ui/gl/gl_gl_api_implementation.cc
+++ b/ui/gl/gl_gl_api_implementation.cc
@@ -7,6 +7,7 @@
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ -19,28 +20,25 @@
 
 namespace gl {
 
-// The GL Api being used. This could be g_real_gl or gl_trace_gl
-static GLApi* g_gl = NULL;
-// A GL Api that calls directly into the driver.
-static RealGLApi* g_real_gl = NULL;
-// A GL Api that does nothing but warn about illegal GL calls without a context
-// current.
-static NoContextGLApi* g_no_context_gl = NULL;
-// A GL Api that calls TRACE and then calls another GL api.
-static TraceGLApi* g_trace_gl = NULL;
-// The GL Api being used for stub contexts. If null, g_gl is used instead.
-static GLApi* g_stub_gl = NULL;
-// GL version used when initializing dynamic bindings.
-static GLVersionInfo* g_version_info = NULL;
+// The GL state for when no context is bound
+static CurrentGL* g_no_context_current_gl = nullptr;
+
+// If the null draw bindings are currently enabled.
+// TODO: Consider adding a new GLApi that no-ops these functions
+static bool g_null_draw_bindings_enabled = false;
+
+// If the GL debug bindings are enabled.
+static bool g_debug_bindings_enabled = false;
 
 namespace {
 
-static inline GLenum GetInternalFormat(GLenum internal_format) {
-  if (!g_version_info->is_es) {
+static inline GLenum GetInternalFormat(const GLVersionInfo* version,
+                                       GLenum internal_format) {
+  if (!version->is_es) {
     if (internal_format == GL_BGRA_EXT || internal_format == GL_BGRA8_EXT)
       return GL_RGBA8;
   }
-  if (g_version_info->is_es3 && g_version_info->is_mesa) {
+  if (version->is_es3 && version->is_mesa) {
     // Mesa bug workaround: Mipmapping does not work when using GL_BGRA_EXT
     if (internal_format == GL_BGRA_EXT)
       return GL_RGBA;
@@ -49,14 +47,14 @@ static inline GLenum GetInternalFormat(GLenum internal_format) {
 }
 
 // TODO(epenner): Could the above function be merged into this and removed?
-static inline GLenum GetTexInternalFormat(GLenum internal_format,
+static inline GLenum GetTexInternalFormat(const GLVersionInfo* version,
+                                          GLenum internal_format,
                                           GLenum format,
                                           GLenum type) {
-  DCHECK(g_version_info);
-  GLenum gl_internal_format = GetInternalFormat(internal_format);
+  GLenum gl_internal_format = GetInternalFormat(version, internal_format);
 
   // g_version_info must be initialized when this function is bound.
-  if (g_version_info->is_es3) {
+  if (version->is_es3) {
     if (internal_format == GL_RED_EXT) {
       // GL_EXT_texture_rg case in ES2.
       switch (type) {
@@ -94,8 +92,8 @@ static inline GLenum GetTexInternalFormat(GLenum internal_format,
     }
   }
 
-  if (type == GL_FLOAT && g_version_info->is_angle && g_version_info->is_es &&
-      g_version_info->major_version == 2) {
+  if (type == GL_FLOAT && version->is_angle && version->is_es &&
+      version->major_version == 2) {
     // It's possible that the texture is using a sized internal format, and
     // ANGLE exposing GLES2 API doesn't support those.
     // TODO(oetuaho@nvidia.com): Remove these conversions once ANGLE has the
@@ -113,8 +111,7 @@ static inline GLenum GetTexInternalFormat(GLenum internal_format,
     }
   }
 
-  if (g_version_info->IsAtLeastGL(2, 1) ||
-      g_version_info->IsAtLeastGLES(3, 0)) {
+  if (version->IsAtLeastGL(2, 1) || version->IsAtLeastGLES(3, 0)) {
     switch (internal_format) {
       case GL_SRGB_EXT:
         gl_internal_format = GL_SRGB8;
@@ -127,7 +124,7 @@ static inline GLenum GetTexInternalFormat(GLenum internal_format,
     }
   }
 
-  if (g_version_info->is_es)
+  if (version->is_es)
     return gl_internal_format;
 
   if (type == GL_FLOAT) {
@@ -195,12 +192,10 @@ static inline GLenum GetTexInternalFormat(GLenum internal_format,
   return gl_internal_format;
 }
 
-static inline GLenum GetTexFormat(GLenum format) {
+static inline GLenum GetTexFormat(const GLVersionInfo* version, GLenum format) {
   GLenum gl_format = format;
 
-  DCHECK(g_version_info);
-  if (g_version_info->IsAtLeastGL(2, 1) ||
-      g_version_info->IsAtLeastGLES(3, 0)) {
+  if (version->IsAtLeastGL(2, 1) || version->IsAtLeastGLES(3, 0)) {
     switch (format) {
       case GL_SRGB_EXT:
         gl_format = GL_RGB;
@@ -216,271 +211,64 @@ static inline GLenum GetTexFormat(GLenum format) {
   return gl_format;
 }
 
-static inline GLenum GetTexType(GLenum type) {
-  if (!g_version_info->is_es) {
+static inline GLenum GetTexType(const GLVersionInfo* version, GLenum type) {
+  if (!version->is_es) {
     if (type == GL_HALF_FLOAT_OES)
       return GL_HALF_FLOAT_ARB;
   }
   return type;
 }
 
-static void GL_BINDING_CALL CustomTexImage2D(
-    GLenum target, GLint level, GLint internalformat,
-    GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type,
-    const void* pixels) {
-  GLenum gl_internal_format = GetTexInternalFormat(
-      internalformat, format, type);
-  GLenum gl_format = GetTexFormat(format);
-  GLenum gl_type = GetTexType(type);
-  g_driver_gl.orig_fn.glTexImage2DFn(
-      target, level, gl_internal_format, width, height, border, gl_format,
-      gl_type, pixels);
-}
-
-static void GL_BINDING_CALL CustomTexSubImage2D(
-      GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width,
-      GLsizei height, GLenum format, GLenum type, const void* pixels) {
-  GLenum gl_format = GetTexFormat(format);
-  GLenum gl_type = GetTexType(type);
-  g_driver_gl.orig_fn.glTexSubImage2DFn(
-      target, level, xoffset, yoffset, width, height, gl_format, gl_type,
-      pixels);
-}
-
-static void GL_BINDING_CALL CustomTexStorage2DEXT(
-    GLenum target, GLsizei levels, GLenum internalformat, GLsizei width,
-    GLsizei height) {
-  GLenum gl_internal_format = GetInternalFormat(internalformat);
-  g_driver_gl.orig_fn.glTexStorage2DEXTFn(
-      target, levels, gl_internal_format, width, height);
-}
-
-static void GL_BINDING_CALL CustomRenderbufferStorageEXT(
-    GLenum target, GLenum internalformat, GLsizei width, GLsizei height) {
-  GLenum gl_internal_format = GetInternalFormat(internalformat);
-  g_driver_gl.orig_fn.glRenderbufferStorageEXTFn(
-      target, gl_internal_format, width, height);
-}
-
-// The ANGLE and IMG variants of glRenderbufferStorageMultisample currently do
-// not support BGRA render buffers so only the EXT one is customized. If
-// GL_CHROMIUM_renderbuffer_format_BGRA8888 support is added to ANGLE then the
-// ANGLE version should also be customized.
-static void GL_BINDING_CALL CustomRenderbufferStorageMultisampleEXT(
-    GLenum target, GLsizei samples, GLenum internalformat, GLsizei width,
-    GLsizei height) {
-  GLenum gl_internal_format = GetInternalFormat(internalformat);
-  g_driver_gl.orig_fn.glRenderbufferStorageMultisampleEXTFn(
-      target, samples, gl_internal_format, width, height);
-}
-
-static void GL_BINDING_CALL
-CustomRenderbufferStorageMultisample(GLenum target,
-                                     GLsizei samples,
-                                     GLenum internalformat,
-                                     GLsizei width,
-                                     GLsizei height) {
-  GLenum gl_internal_format = GetInternalFormat(internalformat);
-  g_driver_gl.orig_fn.glRenderbufferStorageMultisampleFn(
-      target, samples, gl_internal_format, width, height);
-}
-
 }  // anonymous namespace
 
-void DriverGL::InitializeCustomDynamicBindings(GLContext* context) {
-  InitializeDynamicBindings(context);
-
-  DCHECK(orig_fn.glTexImage2DFn == NULL);
-  orig_fn.glTexImage2DFn = fn.glTexImage2DFn;
-  fn.glTexImage2DFn =
-      reinterpret_cast<glTexImage2DProc>(CustomTexImage2D);
-
-  DCHECK(orig_fn.glTexSubImage2DFn == NULL);
-  orig_fn.glTexSubImage2DFn = fn.glTexSubImage2DFn;
-  fn.glTexSubImage2DFn =
-      reinterpret_cast<glTexSubImage2DProc>(CustomTexSubImage2D);
-
-  DCHECK(orig_fn.glTexStorage2DEXTFn == NULL);
-  orig_fn.glTexStorage2DEXTFn = fn.glTexStorage2DEXTFn;
-  fn.glTexStorage2DEXTFn =
-      reinterpret_cast<glTexStorage2DEXTProc>(CustomTexStorage2DEXT);
-
-  DCHECK(orig_fn.glRenderbufferStorageEXTFn == NULL);
-  orig_fn.glRenderbufferStorageEXTFn = fn.glRenderbufferStorageEXTFn;
-  fn.glRenderbufferStorageEXTFn =
-      reinterpret_cast<glRenderbufferStorageEXTProc>(
-      CustomRenderbufferStorageEXT);
-
-  DCHECK(orig_fn.glRenderbufferStorageMultisampleEXTFn == NULL);
-  orig_fn.glRenderbufferStorageMultisampleEXTFn =
-      fn.glRenderbufferStorageMultisampleEXTFn;
-  fn.glRenderbufferStorageMultisampleEXTFn =
-      reinterpret_cast<glRenderbufferStorageMultisampleEXTProc>(
-      CustomRenderbufferStorageMultisampleEXT);
-
-  DCHECK(orig_fn.glRenderbufferStorageMultisampleFn == NULL);
-  orig_fn.glRenderbufferStorageMultisampleFn =
-      fn.glRenderbufferStorageMultisampleFn;
-  fn.glRenderbufferStorageMultisampleFn =
-      reinterpret_cast<glRenderbufferStorageMultisampleProc>(
-          CustomRenderbufferStorageMultisample);
-}
-
-static void GL_BINDING_CALL NullDrawClearFn(GLbitfield mask) {
-  if (!g_driver_gl.null_draw_bindings_enabled)
-    g_driver_gl.orig_fn.glClearFn(mask);
-}
-
-static void GL_BINDING_CALL
-NullDrawDrawArraysFn(GLenum mode, GLint first, GLsizei count) {
-  if (!g_driver_gl.null_draw_bindings_enabled)
-    g_driver_gl.orig_fn.glDrawArraysFn(mode, first, count);
-}
-
-static void GL_BINDING_CALL NullDrawDrawElementsFn(GLenum mode,
-                                                   GLsizei count,
-                                                   GLenum type,
-                                                   const void* indices) {
-  if (!g_driver_gl.null_draw_bindings_enabled)
-    g_driver_gl.orig_fn.glDrawElementsFn(mode, count, type, indices);
-}
-
-void DriverGL::InitializeNullDrawBindings() {
-  DCHECK(orig_fn.glClearFn == NULL);
-  orig_fn.glClearFn = fn.glClearFn;
-  fn.glClearFn = NullDrawClearFn;
-
-  DCHECK(orig_fn.glDrawArraysFn == NULL);
-  orig_fn.glDrawArraysFn = fn.glDrawArraysFn;
-  fn.glDrawArraysFn = NullDrawDrawArraysFn;
-
-  DCHECK(orig_fn.glDrawElementsFn == NULL);
-  orig_fn.glDrawElementsFn = fn.glDrawElementsFn;
-  fn.glDrawElementsFn = NullDrawDrawElementsFn;
-
-  null_draw_bindings_enabled = true;
-}
-
-bool DriverGL::HasInitializedNullDrawBindings() {
-  return orig_fn.glClearFn != NULL && orig_fn.glDrawArraysFn != NULL &&
-         orig_fn.glDrawElementsFn != NULL;
-}
-
-bool DriverGL::SetNullDrawBindingsEnabled(bool enabled) {
-  DCHECK(orig_fn.glClearFn != NULL);
-  DCHECK(orig_fn.glDrawArraysFn != NULL);
-  DCHECK(orig_fn.glDrawElementsFn != NULL);
-
-  bool before = null_draw_bindings_enabled;
-  null_draw_bindings_enabled = enabled;
-  return before;
-}
-
 void InitializeStaticGLBindingsGL() {
-  g_current_gl_context_tls = new base::ThreadLocalPointer<GLApi>;
-  g_driver_gl.InitializeStaticBindings();
-  if (!g_real_gl) {
-    g_real_gl = new RealGLApi();
-    g_trace_gl = new TraceGLApi(g_real_gl);
-    g_no_context_gl = new NoContextGLApi();
-  }
-  g_real_gl->Initialize(&g_driver_gl);
-  g_gl = g_real_gl;
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableGPUServiceTracing)) {
-    g_gl = g_trace_gl;
-  }
-  SetGLToRealGLApi();
-}
-
-GLApi* GetCurrentGLApi() {
-  return g_current_gl_context_tls ? g_current_gl_context_tls->Get() : nullptr;
-}
-
-void SetGLApi(GLApi* api) {
-  g_current_gl_context_tls->Set(api);
-}
-
-void SetGLToRealGLApi() {
-  SetGLApi(g_gl);
-}
-
-void SetGLToStubGLApi() {
-  SetGLApi(g_stub_gl ? g_stub_gl : g_gl);
-}
-
-void SetGLApiToNoContext() {
-  SetGLApi(g_no_context_gl);
-}
-
-void SetStubGLApi(GLApi* api) {
-  g_stub_gl = api;
+  g_current_gl_context_tls = new base::ThreadLocalPointer<CurrentGL>;
+  g_no_context_current_gl = new CurrentGL;
+  g_no_context_current_gl->Api = new NoContextGLApi;
 }
 
-const GLVersionInfo* GetGLVersionInfo() {
-  return g_version_info;
-}
+void ClearBindingsGL() {
+  if (g_no_context_current_gl) {
+    delete g_no_context_current_gl->Api;
+    delete g_no_context_current_gl->Driver;
+    delete g_no_context_current_gl->Version;
+    delete g_no_context_current_gl;
+    g_no_context_current_gl = nullptr;
+  }
 
-void InitializeDynamicGLBindingsGL(GLContext* context) {
-  if (g_version_info)
-    return;
-  g_real_gl->InitializeFilteredExtensions();
-  g_driver_gl.InitializeCustomDynamicBindings(context);
-  DCHECK(context && context->IsCurrent(NULL) && !g_version_info);
-  g_version_info = new GLVersionInfo(
-      context->GetGLVersion().c_str(),
-      context->GetGLRenderer().c_str(),
-      context->GetExtensions().c_str());
+  if (g_current_gl_context_tls) {
+    delete g_current_gl_context_tls;
+    g_current_gl_context_tls = nullptr;
+  }
 }
 
 void InitializeDebugGLBindingsGL() {
-  g_driver_gl.InitializeDebugBindings();
+  g_debug_bindings_enabled = true;
 }
 
-void InitializeNullDrawGLBindingsGL() {
-  g_driver_gl.InitializeNullDrawBindings();
+bool GetDebugGLBindingsInitializedGL() {
+  return g_debug_bindings_enabled;
 }
 
-bool HasInitializedNullDrawGLBindingsGL() {
-  return g_driver_gl.HasInitializedNullDrawBindings();
+bool SetNullDrawGLBindingsEnabled(bool enabled) {
+  bool old_value = g_null_draw_bindings_enabled;
+  g_null_draw_bindings_enabled = enabled;
+  return old_value;
 }
 
-bool SetNullDrawGLBindingsEnabledGL(bool enabled) {
-  return g_driver_gl.SetNullDrawBindingsEnabled(enabled);
+bool GetNullDrawBindingsEnabled() {
+  return g_null_draw_bindings_enabled;
 }
 
-void ClearBindingsGL() {
-  if (g_real_gl) {
-    delete g_real_gl;
-    g_real_gl = NULL;
-  }
-  if (g_trace_gl) {
-    delete g_trace_gl;
-    g_trace_gl = NULL;
-  }
-  if (g_no_context_gl) {
-    delete g_no_context_gl;
-    g_no_context_gl = NULL;
-  }
-  g_gl = NULL;
-  g_stub_gl = NULL;
-  g_driver_gl.ClearBindings();
-  if (g_current_gl_context_tls) {
-    delete g_current_gl_context_tls;
-    g_current_gl_context_tls = NULL;
-  }
-  if (g_version_info) {
-    delete g_version_info;
-    g_version_info = NULL;
-  }
+void SetCurrentGL(CurrentGL* current) {
+  CurrentGL* new_current = current ? current : g_no_context_current_gl;
+  g_current_gl_context_tls->Set(new_current);
 }
 
 GLApi::GLApi() {
 }
 
 GLApi::~GLApi() {
-  if (GetCurrentGLApi() == this)
-    SetGLApi(NULL);
 }
 
 GLApiBase::GLApiBase()
@@ -555,10 +343,121 @@ const GLubyte* RealGLApi::glGetStringiFn(GLenum name, GLuint index) {
   return GLApiBase::glGetStringiFn(name, index);
 }
 
+void RealGLApi::glTexImage2DFn(GLenum target,
+                               GLint level,
+                               GLint internalformat,
+                               GLsizei width,
+                               GLsizei height,
+                               GLint border,
+                               GLenum format,
+                               GLenum type,
+                               const void* pixels) {
+  GLenum gl_internal_format =
+      GetTexInternalFormat(version_.get(), internalformat, format, type);
+  GLenum gl_format = GetTexFormat(version_.get(), format);
+  GLenum gl_type = GetTexType(version_.get(), type);
+  GLApiBase::glTexImage2DFn(target, level, gl_internal_format, width, height,
+                            border, gl_format, gl_type, pixels);
+}
+
+void RealGLApi::glTexSubImage2DFn(GLenum target,
+                                  GLint level,
+                                  GLint xoffset,
+                                  GLint yoffset,
+                                  GLsizei width,
+                                  GLsizei height,
+                                  GLenum format,
+                                  GLenum type,
+                                  const void* pixels) {
+  GLenum gl_format = GetTexFormat(version_.get(), format);
+  GLenum gl_type = GetTexType(version_.get(), type);
+  GLApiBase::glTexSubImage2DFn(target, level, xoffset, yoffset, width, height,
+                               gl_format, gl_type, pixels);
+}
+
+void RealGLApi::glTexStorage2DEXTFn(GLenum target,
+                                    GLsizei levels,
+                                    GLenum internalformat,
+                                    GLsizei width,
+                                    GLsizei height) {
+  GLenum gl_internal_format = GetInternalFormat(version_.get(), internalformat);
+  GLApiBase::glTexStorage2DEXTFn(target, levels, gl_internal_format, width,
+                                 height);
+}
+
+void RealGLApi::glRenderbufferStorageEXTFn(GLenum target,
+                                           GLenum internalformat,
+                                           GLsizei width,
+                                           GLsizei height) {
+  GLenum gl_internal_format = GetInternalFormat(version_.get(), internalformat);
+  GLApiBase::glRenderbufferStorageEXTFn(target, gl_internal_format, width,
+                                        height);
+}
+
+// The ANGLE and IMG variants of glRenderbufferStorageMultisample currently do
+// not support BGRA render buffers so only the EXT one is customized. If
+// GL_CHROMIUM_renderbuffer_format_BGRA8888 support is added to ANGLE then the
+// ANGLE version should also be customized.
+void RealGLApi::glRenderbufferStorageMultisampleEXTFn(GLenum target,
+                                                      GLsizei samples,
+                                                      GLenum internalformat,
+                                                      GLsizei width,
+                                                      GLsizei height) {
+  GLenum gl_internal_format = GetInternalFormat(version_.get(), internalformat);
+  GLApiBase::glRenderbufferStorageMultisampleEXTFn(
+      target, samples, gl_internal_format, width, height);
+}
+
+void RealGLApi::glRenderbufferStorageMultisampleFn(GLenum target,
+                                                   GLsizei samples,
+                                                   GLenum internalformat,
+                                                   GLsizei width,
+                                                   GLsizei height) {
+  GLenum gl_internal_format = GetInternalFormat(version_.get(), internalformat);
+  GLApiBase::glRenderbufferStorageMultisampleFn(
+      target, samples, gl_internal_format, width, height);
+}
+
+void RealGLApi::glClearFn(GLbitfield mask) {
+  if (!g_null_draw_bindings_enabled)
+    GLApiBase::glClearFn(mask);
+}
+
+void RealGLApi::glDrawArraysFn(GLenum mode, GLint first, GLsizei count) {
+  if (!g_null_draw_bindings_enabled)
+    GLApiBase::glDrawArraysFn(mode, first, count);
+}
+
+void RealGLApi::glDrawElementsFn(GLenum mode,
+                                 GLsizei count,
+                                 GLenum type,
+                                 const void* indices) {
+  if (!g_null_draw_bindings_enabled)
+    GLApiBase::glDrawElementsFn(mode, count, type, indices);
+}
+
+void RealGLApi::glClearDepthFn(GLclampd depth) {
+  if (driver_->fn.glClearDepthFn) {
+    GLApiBase::glClearDepthFn(depth);
+  } else {
+    DCHECK(driver_->fn.glClearDepthfFn);
+    GLApiBase::glClearDepthfFn(static_cast<GLclampf>(depth));
+  }
+}
+
+void RealGLApi::glDepthRangeFn(GLclampd z_near, GLclampd z_far) {
+  if (driver_->fn.glDepthRangeFn) {
+    GLApiBase::glDepthRangeFn(z_near, z_far);
+  } else {
+    GLApiBase::glDepthRangefFn(static_cast<GLclampf>(z_near),
+                               static_cast<GLclampf>(z_far));
+  }
+}
+
 void RealGLApi::InitializeFilteredExtensions() {
   if (disabled_exts_.size()) {
     filtered_exts_.clear();
-    if (WillUseGLGetStringForExtensions()) {
+    if (WillUseGLGetStringForExtensions(this)) {
       filtered_exts_str_ =
           FilterGLExtensionList(reinterpret_cast<const char*>(
                                     GLApiBase::glGetStringFn(GL_EXTENSIONS)),
@@ -583,9 +482,17 @@ void RealGLApi::InitializeFilteredExtensions() {
   }
 }
 
+void RealGLApi::set_version(std::unique_ptr<GLVersionInfo> version) {
+  version_ = std::move(version);
+}
+
 TraceGLApi::~TraceGLApi() {
 }
 
+DebugGLApi::DebugGLApi(GLApi* gl_api) : gl_api_(gl_api) {}
+
+DebugGLApi::~DebugGLApi() {}
+
 NoContextGLApi::NoContextGLApi() {
 }