Improve error handling of playback process

file_backend.cpp

@@ -14,7 +14,7 @@ void CFile::open(const char *fname) {
     name = fname;
     file = fopen(fname, "rb");
     if (file == NULL) {
-        throw std::exception();
+        throw NotFoundException(fname);
     }
     fseek(file, 0, SEEK_END);
     len = ftell(file);

file_backend.hpp

@@ -9,15 +9,54 @@
 #include <stdlib.h>
 #include <SDL.h>
 #include <vector>
+#include <fmt/core.h>
+#include <fmt/format.h>
 extern "C" {
 #include <vgmstream.h>
 }
 #include "log.hpp"
+#include <stdlib.h>
+#include <string.h>
 enum class SeekType {
     SET,
     CUR,
     END
 };
+class CustomException : public std::exception {
+	const char *message;
+	protected:
+	void clear_message(bool free_message = true) {
+		if (free_message && this->message != nullptr) {
+			free((void*)this->message);
+		}
+		this->message = nullptr;
+	}
+	public:
+	CustomException() {
+		clear_message(false);
+	}
+	CustomException(std::string message) : CustomException() {
+		set_message(message);
+	}
+	void set_message(std::string message) {
+		clear_message();
+		this->message = strdup(message.c_str());
+	}
+	const char *what() const throw() {
+		return this->message;
+	}
+	~CustomException() {
+		clear_message();
+	}
+};
+class NotFoundException : public CustomException {
+	public:
+	NotFoundException(std::string file) : CustomException() {
+		set_message(fmt::format("File not found: {0}", file));
+	}
+	NotFoundException(const char *file) : NotFoundException(std::string(file)) { }
+};
+
 class File {
     protected:
     size_t len;

playback.cpp

@@ -137,9 +137,14 @@ void PlaybackInstance::Load(const char *file, int idx) {
     SDL_LockAudioDevice(device);
     playback_ready.store(false);
     if (process != nullptr) delete process;
-    process = new PlaybackProcess(file, idx);
+    try {
+    	process = new PlaybackProcess(file, idx);
+    } catch (std::exception e) {
+    	ERROR.writefln("Exception caught when creating process: %s", e.what());
+     	process = nullptr;
+    }
     length = 0.0;
-    if (process->process_running()) {
+    if (process != nullptr && process->process_running()) {
         length = process->get_length();
         auto backend_spec_proxy = process->get_audio_spec();
         memset(&backend_spec, 0, sizeof(backend_spec));
@@ -186,8 +191,7 @@ void PlaybackInstance::Load(const char *file, int idx) {
         load_finished.store(true);
         this->process->set_position(0.0);
     } else {
-        ERROR.writeln("Failed to detect valid playback backend for file!");
+        set_error("Failed to create playback backend.");
-        set_error("Failed to detect valid backend for file.");
         set_signal(PlaybackSignalErrorOccurred);
         delete process;
         process = nullptr;
@@ -387,7 +391,11 @@ void PlaybackInstance::LoopFunction() {
         }
         flag_mutex.unlock();
     }
-    position = process->get_position();
+    if (process) {
+        position = process->get_position();
+    } else {
+        position = 0.0;
+    }
 
 }
 void PlaybackInstance::DeinitLoopFunction() {

playback_process.cpp

@@ -291,6 +291,7 @@ ResetResponse PlaybackProcessServiceImpl::Reset(const ResetProperty *request) {
     return response;
 }
 MaybeError PlaybackProcessServiceImpl::Quit(const QuitCmd *request) {
+	if (process == nullptr) return MaybeError();
     process->done = true;
     cur_backend_lock.get_unsafe()->cleanup();
     return MaybeError();
@@ -302,6 +303,15 @@ MaybeError PlaybackProcessServiceImpl::Init(const InitCommand *cmd) {
     render_ptr.lock().set(new DynPtr(), true);
     lock.clear();
     auto filename = cmd->filename();
+
+    if (!std::filesystem::exists(filename)) {
+    	ErrorResponse *maybe_error = response->mutable_err();
+        maybe_error->set_desc("File not found");
+        maybe_error->set_id("not_found");
+        maybe_error->set_fatal(true);
+        process->done = true;
+        return ret;
+    }
     auto idx = cmd->idx();
     for (auto &backend : PlaybackBackendHelper()) {
         DEBUG.writefln("Trying backend: %s", backend.second->get_name().c_str());
@@ -317,11 +327,10 @@ MaybeError PlaybackProcessServiceImpl::Init(const InitCommand *cmd) {
         break;
     }
     if (!cur_backend_lock.has_value()) {
-        ErrorResponse *maybe_error = new ErrorResponse();
+        ErrorResponse *maybe_error = response->mutable_err();
         maybe_error->set_desc("Couldn't find a backend.");
         maybe_error->set_id("no_backend_for_file");
         maybe_error->set_fatal(true);
-        response->set_allocated_err(maybe_error);
         process->done = true;
         DEBUG.writefln("Couldn't find any backend.");
         return ret;
@@ -401,7 +410,11 @@ PlaybackProcess::PlaybackProcess(std::string filename, int idx) {
     call.mutable_init()->CopyFrom(cmd);
     RPCResponse response = SendCommand(&call);
     if (response.has_err()) {
-        throw std::exception();
+    	this->init_failed = true;
+    	delete other_process;
+     	other_process = nullptr;
+     	auto err = response.err();
+        throw CustomException(err.has_desc() ? err.desc() : err.id());
     }
 }
 bool PlaybackProcess::process_running() {
@@ -577,6 +590,10 @@ AudioSpec *PlaybackProcess::get_audio_spec() {
     return get_property_value<AudioSpec>(PropertyId::SpecProperty);
 }
 PlaybackProcess::~PlaybackProcess() {
+	if (init_failed || other_process == nullptr) {
+		done = true;
+		return;
+	}
     QuitCmd quit_cmd;
     RPCCall call;
     call.mutable_quit()->CopyFrom(quit_cmd);

playback_process.hpp

@@ -45,6 +45,7 @@ class PlaybackProcess  {
     PlaybackProcess *other_process = nullptr;
     PlaybackProcessServiceImpl impl;
     int pid;
+    bool init_failed = false;
     std::mutex start_mutex;
     std::condition_variable started;
     bool is_playback_process = false;

util.hpp

@@ -345,4 +345,4 @@ class DynPtr {
             return get_byte_sized<T>(len * sizeof(T));
         }
     }
-};
+};