Implementing FlushMappedBufferRange in GPU command buffer.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index ceabff8aaa3c69d74399d1b7d302a8c201b7bc25..cd5c8c20a5868e3368a106020dda388bdee3f706 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1101,6 +1101,9 @@ class GLES2DecoderImpl : public GLES2Decoder, public ErrorStateClient {
   void DoScheduleCALayerInUseQueryCHROMIUM(GLsizei count,
                                            const GLuint* textures);
 
+  void DoFlushMappedBufferRange(
+      GLenum target, GLintptr offset, GLsizeiptr size);
+
   // Creates a Program for the given program.
   Program* CreateProgram(GLuint client_id, GLuint service_id) {
     return program_manager()->CreateProgram(client_id, service_id);
@@ -16465,13 +16468,13 @@ error::Error GLES2DecoderImpl::HandleMapBufferRange(
 
   GLbitfield mask = GL_MAP_INVALIDATE_BUFFER_BIT;
   if ((access & mask) == mask) {
-    // TODO(zmo): To be on the safe side, always map
-    // GL_MAP_INVALIDATE_BUFFER_BIT to GL_MAP_INVALIDATE_RANGE_BIT.
+    // To be on the safe side, always map GL_MAP_INVALIDATE_BUFFER_BIT to
+    // GL_MAP_INVALIDATE_RANGE_BIT.
     access = (access & ~GL_MAP_INVALIDATE_BUFFER_BIT);
     access = (access | GL_MAP_INVALIDATE_RANGE_BIT);
   }
-  // TODO(zmo): Always filter out GL_MAP_UNSYNCHRONIZED_BIT to get rid of
-  // undefined behaviors.
+  // Always filter out GL_MAP_UNSYNCHRONIZED_BIT to get rid of undefined
+  // behaviors.
   mask = GL_MAP_READ_BIT | GL_MAP_UNSYNCHRONIZED_BIT;
   if ((access & mask) == mask) {
     LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "MapBufferRange",
@@ -16500,6 +16503,7 @@ error::Error GLES2DecoderImpl::HandleMapBufferRange(
 
 error::Error GLES2DecoderImpl::HandleUnmapBuffer(
     uint32_t immediate_data_size, const void* cmd_data) {
+  const char* func_name = "glUnmapBuffer";
   if (!unsafe_es3_apis_enabled()) {
     return error::kUnknownCommand;
   }
@@ -16508,19 +16512,18 @@ error::Error GLES2DecoderImpl::HandleUnmapBuffer(
   GLenum target = static_cast<GLenum>(c.target);
 
   if (!validators_->buffer_target.IsValid(target)) {
-    LOCAL_SET_GL_ERROR_INVALID_ENUM("glMapBufferRange", target, "target");
+    LOCAL_SET_GL_ERROR_INVALID_ENUM(func_name, target, "target");
     return error::kNoError;
   }
 
   Buffer* buffer = buffer_manager()->GetBufferInfoForTarget(&state_, target);
   if (!buffer) {
-    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "UnmapBuffer", "no buffer bound");
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name, "no buffer bound");
     return error::kNoError;
   }
   const Buffer::MappedRange* mapped_range = buffer->GetMappedRange();
   if (!mapped_range) {
-    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "UnmapBuffer",
-                       "buffer is unmapped");
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name, "buffer is unmapped");
     return error::kNoError;
   }
   if ((mapped_range->access & GL_MAP_WRITE_BIT) == 0 ||
@@ -16553,6 +16556,39 @@ error::Error GLES2DecoderImpl::HandleUnmapBuffer(
   return error::kNoError;
 }
 
+void GLES2DecoderImpl::DoFlushMappedBufferRange(
+    GLenum target, GLintptr offset, GLsizeiptr size) {
+  const char* func_name = "glFlushMappedBufferRange";
+  if (offset < 0) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, func_name, "offset < 0");
+    return;
+  }
+  Buffer* buffer = buffer_manager()->GetBufferInfoForTarget(&state_, target);
+  if (!buffer) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name, "no buffer bound");
+    return;
+  }
+  const Buffer::MappedRange* mapped_range = buffer->GetMappedRange();
+  if (!mapped_range) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name, "buffer is unmapped");
+    return;
+  }
+  if ((mapped_range->access & GL_MAP_FLUSH_EXPLICIT_BIT) == 0) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name,
+        "buffer is mapped without MAP_FLUSH_EXPLICIT_BIT flag");
+    return;
+  }
+  base::CheckedNumeric<GLsizeiptr> range_size = size;
+  range_size += offset;
+  if (!range_size.IsValid() ||
+      range_size.ValueOrDefault(0) > mapped_range->size) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, func_name,
+        "offset + size out-of-bounds");
+    return;
+  }
+  glFlushMappedBufferRange(target, offset, size);

[piman, 2016/08/08 22:55:22]

This in itself won't do anything - the client side wrote the data into the
shared memory, but we need to copy the shared memory into the mapped GL buffer
before doing the flush.

Separately, we also should do the maintenance of the buffer's range cache /
shadow buffer if appropriate (see also crbug.com/491002). Actually, that's also
true of UnmapBuffer if GL_MAP_FLUSH_EXPLICIT_BIT is not set.

+}
+
 // Note that GL_LOST_CONTEXT is specific to GLES.
 // For desktop GL we have to query the reset status proactively.
 void GLES2DecoderImpl::OnContextLostError() {