libvpx: Pull from upstream

source/libvpx/test/video_source.h

 /*
  *  Copyright (c) 2012 The WebM 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 in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #ifndef TEST_VIDEO_SOURCE_H_
 #define TEST_VIDEO_SOURCE_H_
 
 #include <cstdio>
 #include <cstdlib>
 #include <string>
 #include "test/acm_random.h"
 #include "vpx/vpx_encoder.h"
 
 namespace libvpx_test {
 
+// Helper macros to ensure LIBVPX_TEST_DATA_PATH is a quoted string.
+// These are undefined right below GetDataPath
+// NOTE: LIBVPX_TEST_DATA_PATH MUST NOT be a quoted string before
+// Stringification or the GetDataPath will fail at runtime
+#define TO_STRING(S) #S
+#define STRINGIFY(S) TO_STRING(S)
+
+// A simple function to encapsulate cross platform retrieval of test data path
+static std::string GetDataPath() {
+  const char *const data_path = getenv("LIBVPX_TEST_DATA_PATH");
+  if (data_path == NULL) {
+#ifdef LIBVPX_TEST_DATA_PATH
+    // In some environments, we cannot set environment variables
+    // Instead, we set the data path by using a preprocessor symbol
+    // which can be set from make files
+    return STRINGIFY(LIBVPX_TEST_DATA_PATH);
+#else
+    return ".";
+#endif
+  }
+  return data_path;
+}
+
+// Undefining stringification macros because they are not used elsewhere
+#undef TO_STRING
+#undef STRINGIFY
+
 static FILE *OpenTestDataFile(const std::string& file_name) {
-  std::string path_to_source = file_name;
-  const char *kDataPath = getenv("LIBVPX_TEST_DATA_PATH");
-
-  if (kDataPath) {
-    path_to_source = kDataPath;
-    path_to_source += "/";
-    path_to_source += file_name;
-  }
-
+  const std::string path_to_source = GetDataPath() + "/" + file_name;
   return fopen(path_to_source.c_str(), "rb");
 }
 
 // Abstract base class for test video sources, which provide a stream of
 // vpx_image_t images with associated timestamps and duration.
 class VideoSource {
  public:
   virtual ~VideoSource() {}
 
   // Prepare the stream for reading, rewind/open as necessary.
@@ skipping 125 matching lines @@
   virtual const uint8_t *cxdata() const = 0;
 
   virtual const unsigned int frame_size() const = 0;
 
   virtual const unsigned int frame_number() const = 0;
 };
 
 }  // namespace libvpx_test
 
 #endif  // TEST_VIDEO_SOURCE_H_