Add test to verify the behaviour a different return values for data callbacks.

CMakeLists.txt

@@ -238,6 +238,7 @@ if(BUILD_TESTS)
   cubeb_add_test(audio)
   cubeb_add_test(record)
   cubeb_add_test(devices)
+  cubeb_add_test(callback_ret)
 
   add_executable(test_resampler test/test_resampler.cpp src/cubeb_resampler.cpp $<TARGET_OBJECTS:speex>)
   target_include_directories(test_resampler PRIVATE ${gtest_SOURCE_DIR}/include)

test/test_callback_ret.cpp

@@ -0,0 +1,204 @@
+/*
+* Copyright © 2017 Mozilla Foundation
+*
+* This program is made available under an ISC-style license.  See the
+* accompanying file LICENSE for details.
+*/
+
+/* libcubeb api/function test. Test that different return values from user
+   specified callbacks are handled correctly. */
+#include "gtest/gtest.h"
+#if !defined(_XOPEN_SOURCE)
+#define _XOPEN_SOURCE 600
+#endif
+#include <memory>
+#include <atomic>
+#include <string>
+#include "cubeb/cubeb.h"
+#include "common.h"
+
+const uint32_t SAMPLE_FREQUENCY = 48000;
+const cubeb_sample_format SAMPLE_FORMAT = CUBEB_SAMPLE_S16NE;
+
+enum test_direction {
+  INPUT_ONLY,
+  OUTPUT_ONLY,
+  DUPLEX
+};
+
+// Structure which is used by data callbacks to track the total callbacks
+// executed vs the number of callbacks expected.
+struct user_state_callback_ret {
+  std::atomic<int> cb_count{ 0 };
+  std::atomic<int> expected_cb_count{ 0 };
+};
+
+// Data callback that always returns 0
+long data_cb_ret_zero(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  user_state_callback_ret * u = (user_state_callback_ret *) user;
+  // If this is the first time the callback has been called set our expected
+  // callback count
+  if (u->cb_count == 0) {
+    u->expected_cb_count = 1;
+  }
+  u->cb_count++;
+  if (nframes < 1) {
+    // This shouldn't happen
+    EXPECT_TRUE(false) << "nframes should not be 0 in data callback!";
+  }
+  return 0;
+}
+
+// Data callback that always returns nframes - 1
+long data_cb_ret_nframes_minus_one(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  user_state_callback_ret * u = (user_state_callback_ret *)user;
+  // If this is the first time the callback has been called set our expected
+  // callback count
+  if (u->cb_count == 0) {
+    u->expected_cb_count = 1;
+  }
+  u->cb_count++;
+  if (nframes < 1) {
+    // This shouldn't happen
+    EXPECT_TRUE(false) << "nframes should not be 0 in data callback!";
+  }
+  if (outputbuffer != NULL) {
+    // If we have an output buffer insert silence
+    short * ob = (short *) outputbuffer;
+    for (long i = 0; i < nframes - 1; i++) {
+      ob[i] = 0;
+    }
+  }
+  return nframes - 1;
+}
+
+// Data callback that always returns nframes
+long data_cb_ret_nframes(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
+{
+  user_state_callback_ret * u = (user_state_callback_ret *)user;
+  u->cb_count++;
+  // Every callback returns nframes, so every callback is expected
+  u->expected_cb_count++;
+  if (nframes < 1) {
+    // This shouldn't happen
+    EXPECT_TRUE(false) << "nframes should not be 0 in data callback!";
+  }
+  if (outputbuffer != NULL) {
+    // If we have an output buffer insert silence
+    short * ob = (short *) outputbuffer;
+    for (long i = 0; i < nframes; i++) {
+      ob[i] = 0;
+    }
+  }
+  return nframes;
+}
+
+void state_cb_ret(cubeb_stream * stream, void * /*user*/, cubeb_state state)
+{
+  if (stream == NULL)
+    return;
+
+  switch (state) {
+  case CUBEB_STATE_STARTED:
+    fprintf(stderr, "stream started\n"); break;
+  case CUBEB_STATE_STOPPED:
+    fprintf(stderr, "stream stopped\n"); break;
+  case CUBEB_STATE_DRAINED:
+    fprintf(stderr, "stream drained\n"); break;
+  default:
+    fprintf(stderr, "unknown stream state %d\n", state);
+  }
+
+  return;
+}
+
+void run_test_callback(test_direction direction,
+                       cubeb_data_callback data_cb,
+                       const std::string & test_desc) {
+  cubeb * ctx;
+  cubeb_stream * stream;
+  cubeb_stream_params input_params;
+  cubeb_stream_params output_params;
+  int r;
+  user_state_callback_ret user_state;
+  uint32_t latency_frames = 0;
+
+  r = common_init(&ctx, "Cubeb callback return value example");
+  ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
+
+  std::unique_ptr<cubeb, decltype(&cubeb_destroy)>
+    cleanup_cubeb_at_exit(ctx, cubeb_destroy);
+
+  if ((direction == INPUT_ONLY || direction == DUPLEX) &&
+      !has_available_input_device(ctx)) {
+    /* This test needs an available input device, skip it if this host does not
+    * have one. */
+    return;
+  }
+
+  // Setup all params, but only pass them later as required by direction
+  input_params.format = SAMPLE_FORMAT;
+  input_params.rate = SAMPLE_FREQUENCY;
+  input_params.channels = 1;
+  input_params.layout = CUBEB_LAYOUT_MONO;
+  input_params.prefs = CUBEB_STREAM_PREF_NONE;
+  output_params = input_params;
+
+  r = cubeb_get_min_latency(ctx, &input_params, &latency_frames);
+  ASSERT_EQ(r, CUBEB_OK) << "Could not get minimal latency";
+
+  switch (direction)
+  {
+  case INPUT_ONLY:
+    r = cubeb_stream_init(ctx, &stream, "Cubeb callback ret input",
+                          NULL, &input_params, NULL, NULL,
+                          latency_frames, data_cb, state_cb_ret, &user_state);
+    break;
+  case OUTPUT_ONLY:
+    r = cubeb_stream_init(ctx, &stream, "Cubeb callback ret output",
+                          NULL, NULL, NULL, &output_params,
+                          latency_frames, data_cb, state_cb_ret, &user_state);
+    break;
+  case DUPLEX:
+    r = cubeb_stream_init(ctx, &stream, "Cubeb callback ret duplex",
+                          NULL, &input_params, NULL, &output_params,
+                          latency_frames, data_cb, state_cb_ret, &user_state);
+    break;
+  default:
+    ASSERT_TRUE(false) << "Unrecognized test direction!";
+  }
+  EXPECT_EQ(r, CUBEB_OK) << "Error initializing cubeb stream";
+
+  std::unique_ptr<cubeb_stream, decltype(&cubeb_stream_destroy)>
+    cleanup_stream_at_exit(stream, cubeb_stream_destroy);
+
+  cubeb_stream_start(stream);
+  delay(100);
+  cubeb_stream_stop(stream);
+
+  ASSERT_EQ(user_state.expected_cb_count, user_state.cb_count) <<
+    "Callback called unexpected number of times for " << test_desc << "!";
+}
+
+TEST(cubeb, test_input_callback)
+{
+  run_test_callback(INPUT_ONLY, data_cb_ret_zero, "input only, return 0");
+  run_test_callback(INPUT_ONLY, data_cb_ret_nframes_minus_one, "input only, return nframes - 1");
+  run_test_callback(INPUT_ONLY, data_cb_ret_nframes, "input only, return nframes");
+}
+
+TEST(cubeb, test_output_callback)
+{
+  run_test_callback(OUTPUT_ONLY, data_cb_ret_zero, "output only, return 0");
+  run_test_callback(OUTPUT_ONLY, data_cb_ret_nframes_minus_one, "output only, return nframes - 1");
+  run_test_callback(OUTPUT_ONLY, data_cb_ret_nframes, "output only, return nframes");
+}
+
+TEST(cubeb, test_duplex_callback)
+{
+  run_test_callback(DUPLEX, data_cb_ret_zero, "duplex, return 0");
+  run_test_callback(DUPLEX, data_cb_ret_nframes_minus_one, "duplex, return nframes - 1");
+  run_test_callback(DUPLEX, data_cb_ret_nframes, "duplex, return nframes");
+}