Clean up some of the shader compilation code.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 7032 matching lines @@
           GL_INVALID_OPERATION,
           "GetMaxValueInBufferCHROMIUM", "range out of bounds for buffer");
     }
   }
   return max_vertex_accessed;
 }
 
 void GLES2DecoderImpl::DoShaderSource(
     GLuint client_id, GLsizei count, const char** data, const GLint* length) {
   std::string str;
-  for (GLsizei ii = 0; ii < count; ++ii) {
-    str.append(data[ii]);
+  if (length) {
+    for (GLsizei ii = 0; ii < count; ++ii) {
+      str.append(data[ii], length[ii]);

[vmiura, 2015/02/04 05:49:02]

I believe the spec is that if length[ii] is NULL then it should be treated as a
0 terminated string.

[vmiura, 2015/02/04 05:55:51]

Btw, is this a bug fix that should be in it's own CL?

[David Yen, 2015/02/04 19:13:33]

Done. Strictly speaking this is not a bug fix. It is just a micro optimization
because the GLES2Implementation::ShaderSource() does the correct evaluations and
always passes a correct length array. To be sure I added a unit test also, the
unit tests passes without any changes.

+    }
+  } else {
+    for (GLsizei ii = 0; ii < count; ++ii) {
+      str.append(data[ii]);
+    }
   }
   Shader* shader = GetShaderInfoNotProgram(client_id, "glShaderSource");
   if (!shader) {
     return;
   }
   // Note: We don't actually call glShaderSource here. We wait until
-  // the call to glCompileShader.
+  // we actually compile the shader.
   shader->set_source(str);
 }
 
 void GLES2DecoderImpl::DoTransformFeedbackVaryings(
     GLuint client_program_id, GLsizei count, const char* const* varyings,
     GLenum buffer_mode) {
   Program* program = GetProgramInfoNotShader(
       client_program_id, "glTransformFeedbackVaryings");
   if (!program) {
     return;
@@ skipping 4596 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu