Split asset reload platform policy

src/platform_api/asset_file_load_policy.cpp

@@ -5,29 +5,75 @@
 
 namespace pp::platform {
 
+AssetFileLoadDecision plan_asset_file_load_with_probe(
+    PlatformFamily family,
+    bool already_loaded,
+    std::int64_t previous_last_write_time,
+    AssetFileTimestampProbe probe) noexcept
+{
+    if (platform_uses_asset_file_mtime_reload(family))
+    {
+        if (!probe.file_exists)
+            return { false, false, previous_last_write_time };
+
+        if (probe.last_write_time <= previous_last_write_time)
+            return { false, false, previous_last_write_time };
+
+        return { true, true, probe.last_write_time };
+    }
+
+    if (already_loaded)
+        return { false, true, previous_last_write_time };
+
+    return { true, true, previous_last_write_time };
+}
+
+AssetFileLoadDecision plan_asset_file_load_for_platform(
+    PlatformFamily family,
+    std::string_view absolute_path,
+    bool already_loaded,
+    std::int64_t previous_last_write_time)
+{
+    if (!platform_uses_asset_file_mtime_reload(family))
+    {
+        return plan_asset_file_load_with_probe(
+            family,
+            already_loaded,
+            previous_last_write_time,
+            {});
+    }
+
+    struct stat file_info {};
+    const std::string path(absolute_path);
+    if (stat(path.c_str(), &file_info) != 0)
+    {
+        return plan_asset_file_load_with_probe(
+            family,
+            already_loaded,
+            previous_last_write_time,
+            {});
+    }
+
+    return plan_asset_file_load_with_probe(
+        family,
+        already_loaded,
+        previous_last_write_time,
+        {
+            true,
+            static_cast<std::int64_t>(file_info.st_mtime),
+        });
+}
+
 AssetFileLoadDecision plan_asset_file_load(
     std::string_view absolute_path,
     bool already_loaded,
     std::int64_t previous_last_write_time)
 {
-#if defined(_WIN32) || defined(__OSX__)
-    struct stat file_info {};
-    const std::string path(absolute_path);
-    if (stat(path.c_str(), &file_info) != 0)
-        return { false, false, previous_last_write_time };
-
-    const auto current_last_write_time = static_cast<std::int64_t>(file_info.st_mtime);
-    if (current_last_write_time <= previous_last_write_time)
-        return { false, false, previous_last_write_time };
-
-    return { true, true, current_last_write_time };
-#else
-    if (already_loaded)
-        return { false, true, previous_last_write_time };
-
-    (void)absolute_path;
-    return { true, true, previous_last_write_time };
-#endif
+    return plan_asset_file_load_for_platform(
+        current_platform_family(),
+        absolute_path,
+        already_loaded,
+        previous_last_write_time);
 }
 
 }

src/platform_api/asset_file_load_policy.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "platform_api/platform_policy.h"
+
 #include <cstdint>
 #include <string_view>
 
@@ -11,6 +13,23 @@ struct AssetFileLoadDecision {
     std::int64_t last_write_time = 0;
 };
 
+struct AssetFileTimestampProbe {
+    bool file_exists = false;
+    std::int64_t last_write_time = 0;
+};
+
+[[nodiscard]] AssetFileLoadDecision plan_asset_file_load_with_probe(
+    PlatformFamily family,
+    bool already_loaded,
+    std::int64_t previous_last_write_time,
+    AssetFileTimestampProbe probe) noexcept;
+
+[[nodiscard]] AssetFileLoadDecision plan_asset_file_load_for_platform(
+    PlatformFamily family,
+    std::string_view absolute_path,
+    bool already_loaded,
+    std::int64_t previous_last_write_time);
+
 [[nodiscard]] AssetFileLoadDecision plan_asset_file_load(
     std::string_view absolute_path,
     bool already_loaded,

src/platform_api/platform_policy.cpp

@@ -43,6 +43,11 @@ bool platform_enables_live_asset_reloading(PlatformFamily family) noexcept
     return family == PlatformFamily::windows || family == PlatformFamily::macos;
 }
 
+bool platform_uses_asset_file_mtime_reload(PlatformFamily family) noexcept
+{
+    return family == PlatformFamily::windows || family == PlatformFamily::macos;
+}
+
 bool platform_saves_native_ui_state(PlatformFamily family) noexcept
 {
     return family == PlatformFamily::windows || family == PlatformFamily::macos;

src/platform_api/platform_policy.h

@@ -23,6 +23,7 @@ enum class PlatformFamily {
 [[nodiscard]] bool platform_publishes_exported_images(PlatformFamily family) noexcept;
 [[nodiscard]] bool platform_flushes_persistent_storage(PlatformFamily family) noexcept;
 [[nodiscard]] bool platform_enables_live_asset_reloading(PlatformFamily family) noexcept;
+[[nodiscard]] bool platform_uses_asset_file_mtime_reload(PlatformFamily family) noexcept;
 [[nodiscard]] bool platform_saves_native_ui_state(PlatformFamily family) noexcept;
 [[nodiscard]] bool platform_supports_working_directory_picker(PlatformFamily family) noexcept;
 [[nodiscard]] bool platform_uses_prepared_file_writes(PlatformFamily family) noexcept;