Extract web platform service boundary

src/platform_api/platform_services.cpp

@@ -1,7 +1,66 @@
 #include "platform_api/platform_services.h"
 
+#include "platform_api/platform_policy.h"
+
 namespace pp::platform {
 namespace {
+
+class DefaultWebPlatformServices final : public WebPlatformServices {
+public:
+    void publish_exported_image(std::string_view path) override
+    {
+        (void)path;
+    }
+
+    void flush_persistent_storage() override
+    {
+    }
+
+    [[nodiscard]] int default_canvas_resolution() override
+    {
+        return platform_default_canvas_resolution(PlatformFamily::webgl);
+    }
+
+    void save_prepared_file(
+        std::string_view path,
+        std::string_view suggested_name,
+        PreparedFileCallback callback) override
+    {
+        (void)suggested_name;
+        callback(std::string(path), false);
+    }
+};
+
+WebPlatformServices* g_injected_web_platform_services = nullptr;
+
 static_assert(sizeof(PlatformServices*) == sizeof(void*));
 }
+
+WebPlatformServices& default_web_platform_services()
+{
+    static DefaultWebPlatformServices services;
+    return services;
+}
+
+WebPlatformServices* injected_web_platform_services() noexcept
+{
+    return g_injected_web_platform_services;
+}
+
+void set_injected_web_platform_services(WebPlatformServices* services) noexcept
+{
+    g_injected_web_platform_services = services;
+}
+
+WebPlatformServices& resolve_web_platform_services(WebPlatformServices& fallback) noexcept
+{
+    if (auto* services = injected_web_platform_services())
+        return *services;
+    return fallback;
+}
+
+WebPlatformServices& active_web_platform_services()
+{
+    return resolve_web_platform_services(default_web_platform_services());
+}
 }

src/platform_api/platform_services.h

@@ -90,4 +90,23 @@ public:
         PreparedFileCallback callback) = 0;
 };
 
+class WebPlatformServices {
+public:
+    virtual ~WebPlatformServices() = default;
+
+    virtual void publish_exported_image(std::string_view path) = 0;
+    virtual void flush_persistent_storage() = 0;
+    [[nodiscard]] virtual int default_canvas_resolution() = 0;
+    virtual void save_prepared_file(
+        std::string_view path,
+        std::string_view suggested_name,
+        PreparedFileCallback callback) = 0;
+};
+
+[[nodiscard]] WebPlatformServices& default_web_platform_services();
+[[nodiscard]] WebPlatformServices* injected_web_platform_services() noexcept;
+void set_injected_web_platform_services(WebPlatformServices* services) noexcept;
+[[nodiscard]] WebPlatformServices& resolve_web_platform_services(WebPlatformServices& fallback) noexcept;
+[[nodiscard]] WebPlatformServices& active_web_platform_services();
+
 }