Move the logic for which AudioProvider to create out of AudioController

Audio providers should be responsible for determining whether or not
they can open a URI, since it's not really possible for anything else
to. As such move the (lack of) parsing of dummy audio URIs to
DummyAudioProvider, and try to create DummyAudioProviders in
AudioProvider::CreateProvider.

aegisub/src/audio_controller.cpp

@@ -163,78 +163,17 @@ void AudioController::OpenAudio(const wxString &url)
 	if (!url)
 		throw agi::InternalError("AudioController::OpenAudio() was passed an empty string. This must not happen.", 0);
 
-	wxString path_part;
-
 	AudioProvider *new_provider = 0;
-
-	if (url.StartsWith("dummy-audio:", &path_part))
-	{
-		/*
-		 * scheme            ::= "dummy-audio" ":" signal-specifier "?" signal-parameters
-		 * signal-specifier  ::= "silence" | "noise" | "sine" "/" frequency
-		 * frequency         ::= integer
-		 * signal-parameters ::= signal-parameter [ "&" signal-parameters ]
-		 * signal-parameter  ::= signal-parameter-name "=" integer
-		 * signal-parameter-name ::= "sr" | "bd" | "ch" | "ln"
-		 *
-		 * Signal types:
-		 * "silence", a silent signal is generated.
-		 * "noise", a white noise signal is generated.
-		 * "sine", a sine wave is generated at the specified frequency.
-		 *
-		 * Signal parameters:
-		 * "sr", sample rate to generate signal at.
-		 * "bd", bit depth to generate signal at (usually 16).
-		 * "ch", number of channels to generate, usually 1 or 2. The same signal is generated
-		 *       in every channel even if one would be LFE.
-		 * "ln", length of signal in samples. ln/sr gives signal length in seconds.
-		 */
-		new_provider = new DummyAudioProvider(5*30*60*1000, path_part.StartsWith("noise"));
+	try {
+		new_provider = AudioProviderFactory::GetProvider(url);
+		StandardPaths::SetPathValue("?audio", wxFileName(url).GetPath());
 	}
-	else if (url.StartsWith("video-audio:", &path_part))
-	{
-		/*
-		 * scheme      ::= "video-audio" ":" stream-type
-		 * stream-type ::= "stream" | "cache"
-		 *
-		 * Stream types:
-		 *
-		 * "stream", the audio is streamed as required directly from the video provider,
-		 * and cannot be used to drive an audio display. Seeking is unreliable.
-		 *
-		 * "cache", the entire audio is cached to memory or disk. Audio displays can be
-		 * driven and seeking is reliable. Opening takes longer because the entire audio
-		 * stream has to be decoded and stored.
-		 */
+	catch (agi::UserCancelException const&) {
+		throw;
 	}
-	else if (url.StartsWith("file:", &path_part))
-	{
-		/*
-		 * scheme    ::= "file" ":" "//" file-system-path
-		 *
-		 * On Unix-like systems, the file system path is regular. On Windows-systems, the
-		 * path uses forward slashes instead of back-slashes and the drive letter is
-		 * preceded by a slash.
-		 *
-		 * URL-encoding??
-		 */
-	}
-	else
-	{
-		/*
-		 * Assume it's not a URI but instead a filename in the platform's native format.
-		 */
-		try {
-			new_provider = AudioProviderFactory::GetProvider(url);
-			StandardPaths::SetPathValue("?audio", wxFileName(url).GetPath());
-		}
-		catch (agi::UserCancelException const&) {
-			throw;
-		}
-		catch (...) {
-			config::mru->Remove("Audio", STD_STR(url));
-			throw;
-		}
+	catch (...) {
+		config::mru->Remove("Audio", STD_STR(url));
+		throw;
 	}
 
 	CloseAudio();

aegisub/src/audio_provider.cpp

@@ -39,6 +39,7 @@
 
 #include "audio_provider_avs.h"
 #include "audio_provider_convert.h"
+#include "audio_provider_dummy.h"
 #include "audio_provider_ffmpegsource.h"
 #include "audio_provider_hd.h"
 #include "audio_provider_lock.h"
@@ -146,8 +147,10 @@ AudioProvider *AudioProviderFactory::GetProvider(wxString const& filename) {
 	provider_creator creator;
 	AudioProvider *provider = nullptr;
 
+	provider = creator.try_create("Dummy audio provider", [&]() { return new DummyAudioProvider(filename); });
+
 	// Try a PCM provider first
-	if (!OPT_GET("Provider/Audio/PCM/Disable")->GetBool())
+	if (!provider && !OPT_GET("Provider/Audio/PCM/Disable")->GetBool())
 		provider = creator.try_create("PCM audio provider", [&]() { return CreatePCMAudioProvider(filename); });
 
 	if (!provider) {

aegisub/src/audio_provider_dummy.cpp

@@ -37,24 +37,49 @@
 #include "audio_provider_dummy.h"
 #include "utils.h"
 
-DummyAudioProvider::DummyAudioProvider(unsigned long dur_ms, bool _noise) {
-	noise = _noise;
+#include <wx/uri.h>
+
+/*
+ * scheme            ::= "dummy-audio" ":" signal-specifier "?" signal-parameters
+ * signal-specifier  ::= "silence" | "noise" | "sine" "/" frequency
+ * frequency         ::= integer
+ * signal-parameters ::= signal-parameter [ "&" signal-parameters ]
+ * signal-parameter  ::= signal-parameter-name "=" integer
+ * signal-parameter-name ::= "sr" | "bd" | "ch" | "ln"
+ *
+ * Signal types:
+ * "silence", a silent signal is generated.
+ * "noise", a white noise signal is generated.
+ * "sine", a sine wave is generated at the specified frequency.
+ *
+ * Signal parameters:
+ * "sr", sample rate to generate signal at.
+ * "bd", bit depth to generate signal at (usually 16).
+ * "ch", number of channels to generate, usually 1 or 2. The same signal is generated
+ *       in every channel even if one would be LFE.
+ * "ln", length of signal in samples. ln/sr gives signal length in seconds.
+ */
+DummyAudioProvider::DummyAudioProvider(wxString uri)
+{
+	wxURI parsed(uri);
+	if (parsed.GetScheme() != "dummy-audio")
+		throw agi::FileNotFoundError("Not a dummy audio URI");
+
+	noise = parsed.GetPath() == "noise";
 	channels = 1;
 	sample_rate = 44100;
 	bytes_per_sample = 2;
 	float_samples = false;
-	num_samples = (int64_t)dur_ms * sample_rate / 1000;
+	num_samples = (int64_t)5*30*60*1000 * sample_rate / 1000;
 }
 
 void DummyAudioProvider::FillBuffer(void *buf, int64_t, int64_t count) const {
-	short *workbuf = (short*)buf;
-
 	if (noise) {
+		short *workbuf = (short*)buf;
 		while (count-- > 0)
 			*workbuf++ = (rand() - RAND_MAX/2) * 10000 / RAND_MAX;
 	}
 	else {
-		while (count-- > 0)
-			*workbuf++ = 0;
+		memset(buf, 0, count * bytes_per_sample);
 	}
 }

aegisub/src/audio_provider_dummy.h

@@ -39,7 +39,7 @@ class DummyAudioProvider : public AudioProvider {
 	void FillBuffer(void *buf, int64_t start, int64_t count) const;
 
 public:
-	DummyAudioProvider(unsigned long dur_ms, bool _noise);
+	DummyAudioProvider(wxString uri);
 
 	bool AreSamplesNativeEndian() const { return true; }
 };