fix(fsutils): fix resource finding in AppImage

Signed-off-by: k4yt3x <i@k4yt3x.com>

include/libvideo2x/fsutils.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <filesystem>
+#include <optional>
 #include <string>
 
 namespace video2x {
@@ -20,9 +21,9 @@ typedef std::wstring StringType;
 typedef std::string StringType;
 #endif
 
-bool filepath_is_readable(const std::filesystem::path& path);
+bool file_is_readable(const std::filesystem::path& path);
 
-std::filesystem::path find_resource_file(const std::filesystem::path& path);
+std::optional<std::filesystem::path> find_resource(const std::filesystem::path& resource);
 
 std::string path_to_u8string(const std::filesystem::path& path);
 

src/filter_libplacebo.cpp

@@ -42,20 +42,20 @@ FilterLibplacebo::~FilterLibplacebo() {
 
 int FilterLibplacebo::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVBufferRef*) {
     // Construct the shader path
-    std::filesystem::path shader_full_path;
-    if (fsutils::filepath_is_readable(shader_path_)) {
+    std::optional<std::filesystem::path> shader_full_path = std::nullopt;
+    if (fsutils::file_is_readable(shader_path_)) {
         // If the shader path is directly readable, use it
         shader_full_path = shader_path_;
     } else {
         // Construct the fallback path using std::filesystem
-        shader_full_path = fsutils::find_resource_file(
+        shader_full_path = fsutils::find_resource(
             std::filesystem::path(STR("models")) / STR("libplacebo") /
             (fsutils::path_to_string_type(shader_path_) + STR(".glsl"))
         );
     }
 
     // Check if the shader file exists
-    if (!std::filesystem::exists(shader_full_path)) {
+    if (!shader_full_path.has_value()) {
         logger()->error("libplacebo shader file not found: '{}'", shader_path_.u8string());
         return -1;
     }
@@ -73,7 +73,7 @@ int FilterLibplacebo::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVB
         width_,
         height_,
         vk_device_index_,
-        shader_full_path
+        shader_full_path.value()
     );
 
     // Set these resources to nullptr since they are already freed by `avfilter_graph_free`

src/filter_realcugan.cpp

@@ -66,20 +66,22 @@ int FilterRealcugan::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVBu
         std::filesystem::path(STR("models")) / STR("realcugan") / model_name_ / bin_file_name;
 
     // Get the full paths using a function that possibly modifies or validates the path
-    std::filesystem::path model_param_full_path = fsutils::find_resource_file(model_param_path);
-    std::filesystem::path model_bin_full_path = fsutils::find_resource_file(model_bin_path);
+    std::optional<std::filesystem::path> model_param_full_path =
+        fsutils::find_resource(model_param_path);
+    std::optional<std::filesystem::path> model_bin_full_path =
+        fsutils::find_resource(model_bin_path);
 
     // Check if the model files exist
-    if (!std::filesystem::exists(model_param_full_path)) {
-        logger()->error("RealCUGAN model param file not found: {}", model_param_path.u8string());
+    if (!model_param_full_path.has_value()) {
+        logger()->error("Real-CUGAN model param file not found: {}", model_param_path.u8string());
         return -1;
     }
-    if (!std::filesystem::exists(model_bin_full_path)) {
-        logger()->error("RealCUGAN model bin file not found: {}", model_bin_path.u8string());
+    if (!model_bin_full_path.has_value()) {
+        logger()->error("Real-CUGAN model bin file not found: {}", model_bin_path.u8string());
         return -1;
     }
 
-    // Create a new RealCUGAN instance
+    // Create a new Real-CUGAN instance
     realcugan_ = new RealCUGAN(gpuid_, tta_mode_, num_threads_);
 
     // Store the time bases
@@ -88,8 +90,8 @@ int FilterRealcugan::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVBu
     out_pix_fmt_ = enc_ctx->pix_fmt;
 
     // Load the model
-    if (realcugan_->load(model_param_full_path, model_bin_full_path) != 0) {
-        logger()->error("Failed to load RealCUGAN model");
+    if (realcugan_->load(model_param_full_path.value(), model_bin_full_path.value()) != 0) {
+        logger()->error("Failed to load Real-CUGAN model");
         return -1;
     }
 
@@ -176,7 +178,7 @@ int FilterRealcugan::filter(AVFrame* in_frame, AVFrame** out_frame) {
 
     ret = realcugan_->process(in_mat, out_mat);
     if (ret != 0) {
-        logger()->error("RealCUGAN processing failed");
+        logger()->error("Real-CUGAN processing failed");
         return ret;
     }
 

src/filter_realesrgan.cpp

@@ -45,20 +45,22 @@ int FilterRealesrgan::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVB
     model_bin_path = std::filesystem::path(STR("models")) / STR("realesrgan") / bin_file_name;
 
     // Get the full paths using a function that possibly modifies or validates the path
-    std::filesystem::path model_param_full_path = fsutils::find_resource_file(model_param_path);
-    std::filesystem::path model_bin_full_path = fsutils::find_resource_file(model_bin_path);
+    std::optional<std::filesystem::path> model_param_full_path =
+        fsutils::find_resource(model_param_path);
+    std::optional<std::filesystem::path> model_bin_full_path =
+        fsutils::find_resource(model_bin_path);
 
     // Check if the model files exist
-    if (!std::filesystem::exists(model_param_full_path)) {
-        logger()->error("RealESRGAN model param file not found: {}", model_param_path.u8string());
+    if (!model_param_full_path.has_value()) {
+        logger()->error("Real-ESRGAN model param file not found: {}", model_param_path.u8string());
         return -1;
     }
-    if (!std::filesystem::exists(model_bin_full_path)) {
-        logger()->error("RealESRGAN model bin file not found: {}", model_bin_path.u8string());
+    if (!model_bin_full_path.has_value()) {
+        logger()->error("Real-ESRGAN model bin file not found: {}", model_bin_path.u8string());
         return -1;
     }
 
-    // Create a new RealESRGAN instance
+    // Create a new Real-ESRGAN instance
     realesrgan_ = new RealESRGAN(gpuid_, tta_mode_);
 
     // Store the time bases
@@ -67,12 +69,12 @@ int FilterRealesrgan::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVB
     out_pix_fmt_ = enc_ctx->pix_fmt;
 
     // Load the model
-    if (realesrgan_->load(model_param_full_path, model_bin_full_path) != 0) {
-        logger()->error("Failed to load RealESRGAN model");
+    if (realesrgan_->load(model_param_full_path.value(), model_bin_full_path.value()) != 0) {
+        logger()->error("Failed to load Real-ESRGAN model");
         return -1;
     }
 
-    // Set RealESRGAN parameters
+    // Set Real-ESRGAN parameters
     realesrgan_->scale = scaling_factor_;
     realesrgan_->prepadding = 10;
 
@@ -108,7 +110,7 @@ int FilterRealesrgan::filter(AVFrame* in_frame, AVFrame** out_frame) {
 
     ret = realesrgan_->process(in_mat, out_mat);
     if (ret != 0) {
-        logger()->error("RealESRGAN processing failed");
+        logger()->error("Real-ESRGAN processing failed");
         return ret;
     }
 

src/fsutils.cpp

@@ -54,13 +54,13 @@ static std::filesystem::path get_executable_directory() {
 }
 #endif  // _WIN32
 
-bool filepath_is_readable(const std::filesystem::path& path) {
+bool file_is_readable(const std::filesystem::path& path) {
 #if _WIN32
     FILE* fp = _wfopen(path.c_str(), L"rb");
-#else   // _WIN32
+#else
     FILE* fp = fopen(path.c_str(), "rb");
-#endif  // _WIN32
-    if (!fp) {
+#endif
+    if (fp == nullptr) {
         return false;
     }
 
@@ -68,16 +68,40 @@ bool filepath_is_readable(const std::filesystem::path& path) {
     return true;
 }
 
-std::filesystem::path find_resource_file(const std::filesystem::path& path) {
-    if (filepath_is_readable(path)) {
-        return path;
+std::optional<std::filesystem::path> find_resource(const std::filesystem::path& resource) {
+    // Build a list of candidate directories
+    std::vector<std::filesystem::path> candidates;
+
+    // 1. The resource's path as provided
+    candidates.push_back(resource);
+
+#ifndef _WIN32
+    // 2. AppImage's mounted directory
+    if (const char* appdir = std::getenv("APPDIR")) {
+        candidates.push_back(
+            std::filesystem::path(appdir) / "usr" / "share" / "video2x" / resource
+        );
     }
 
-    if (filepath_is_readable(std::filesystem::path("/usr/share/video2x/") / path)) {
-        return std::filesystem::path("/usr/share/video2x/") / path;
+    // 3. The Linux standard local data directory
+    candidates.push_back(std::filesystem::path("/usr/local/share/video2x") / resource);
+
+    // 4. The Linux standard data directory
+    candidates.push_back(std::filesystem::path("/usr/share/video2x") / resource);
+#endif
+
+    // 5. The executable's parent directory
+    candidates.push_back(get_executable_directory() / resource);
+
+    // Iterate over the candidate directories and return the first readable file
+    for (const auto& candidate : candidates) {
+        if (file_is_readable(candidate) || std::filesystem::is_directory(candidate)) {
+            return candidate;
+        }
     }
 
-    return get_executable_directory() / path;
+    // Return nullopt if the resource was not found
+    return std::nullopt;
 }
 
 std::string path_to_u8string(const std::filesystem::path& path) {
@@ -119,11 +143,11 @@ std::string wstring_to_u8string(const std::wstring& wstr) {
     );
     return converted_str;
 }
-#else
+#else   // _WIN32
 std::string wstring_to_u8string(const std::string& str) {
     return str;
 }
-#endif
+#endif  // _WIN32
 
 fsutils::StringType path_to_string_type(const std::filesystem::path& path) {
 #if _WIN32

src/interpolator_rife.cpp

@@ -35,17 +35,15 @@ InterpolatorRIFE::~InterpolatorRIFE() {
 
 int InterpolatorRIFE::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVBufferRef*) {
     // Construct the model directory path using std::filesystem
-    std::filesystem::path model_param_dir;
-
-    // Find the model paths by model name if provided
-    model_param_dir = std::filesystem::path(STR("models")) / STR("rife") / model_name_;
+    std::filesystem::path model_dir =
+        std::filesystem::path(STR("models")) / STR("rife") / model_name_;
 
     // Get the full paths using a function that possibly modifies or validates the path
-    std::filesystem::path model_param_full_path = fsutils::find_resource_file(model_param_dir);
+    std::optional<std::filesystem::path> model_dir_full_path = fsutils::find_resource(model_dir);
 
     // Check if the model files exist
-    if (!std::filesystem::exists(model_param_full_path)) {
-        logger()->error("RIFE model param directory not found: {}", model_param_dir.u8string());
+    if (!model_dir_full_path.has_value()) {
+        logger()->error("RIFE model param directory not found: {}", model_dir.u8string());
         return -1;
     }
 
@@ -73,7 +71,7 @@ int InterpolatorRIFE::init(AVCodecContext* dec_ctx, AVCodecContext* enc_ctx, AVB
     out_pix_fmt_ = enc_ctx->pix_fmt;
 
     // Load the model
-    if (rife_->load(model_param_full_path) != 0) {
+    if (rife_->load(model_dir_full_path.value()) != 0) {
         logger()->error("Failed to load RIFE model");
         return -1;
     }