Own Linux platform services and narrow legacy fallback

CMakeLists.txt

@@ -304,12 +304,18 @@ add_library(pp_platform_linux STATIC
 target_include_directories(pp_platform_linux
     PUBLIC
         "${CMAKE_CURRENT_SOURCE_DIR}/src")
+target_include_directories(pp_platform_linux
+    PRIVATE
+        ${PP_LEGACY_INCLUDE_DIRS})
 target_link_libraries(pp_platform_linux
     PUBLIC
         pp_platform_api
         pp_project_options
     PRIVATE
         pp_project_warnings)
+if(TARGET pp_renderer_gl)
+    target_link_libraries(pp_platform_linux PUBLIC pp_renderer_gl)
+endif()
 
 add_library(pp_platform_android STATIC
     ${PP_PLATFORM_ANDROID_SOURCES})

docs/modernization/debt.md

@@ -18,6 +18,12 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Reductions
 
+- 2026-06-17: `DEBT-0016`/`DEBT-0017`/`DEBT-0051` were narrowed again.
+  `src/platform_linux/linux_platform_services.*` now owns the concrete Linux
+  `PlatformServices` implementation and `linux/src/main.cpp` now binds that
+  owned service directly, so `src/platform_legacy/legacy_platform_services.*`
+  no longer carries the touched Linux storage-path, GLFW render-context,
+  app-close, desktop picker, default-render-target, or FPS-reporting branches.
 - 2026-06-17: `DEBT-0016`/`DEBT-0017` were narrowed again.
   `src/platform_android/android_platform_services.*` now owns the concrete
   Android `PlatformServices` implementation and

docs/modernization/roadmap.md

@@ -70,6 +70,19 @@ What is already real:
 - `pp_app_core`
 
 Latest slice:
+- `src/platform_linux/linux_platform_services.*` now owns the concrete Linux
+  `PlatformServices` implementation and `create_platform_services(...)`
+  instead of leaving the live Linux execution surface inside
+  `platform_legacy`.
+- `linux/src/main.cpp` now binds that owned Linux `PlatformServices` instance
+  into `App` directly at the Linux entrypoint.
+- The touched Linux storage-path setup, GLFW render-context acquire/present,
+  app-close dispatch, default render-target binding, desktop file picking, and
+  FPS reporting now route through `src/platform_linux/linux_platform_services.*`
+  instead of the cross-platform fallback adapter.
+- `src/platform_legacy/legacy_platform_services.*` no longer carries the
+  touched Linux method branches, so the retained fallback adapter is narrower
+  again and now focused on the Web path plus generic fallback policy.
 - `src/platform_android/android_platform_services.*` now owns the concrete
   Android `PlatformServices` implementation and `create_platform_services()`
   instead of leaving the live Android execution surface inside
@@ -82,8 +95,7 @@ Latest slice:
   cross-platform fallback adapter.
 - `src/platform_legacy/legacy_platform_services.*` no longer carries the
   Android bridge/configuration surface or the touched Android method branches,
-  so the retained fallback adapter is narrower again and now focused on the
+  so the retained fallback adapter was narrowed again before the Linux cut.
-  Linux/Web path plus generic fallback policy.
 - `src/platform_apple/apple_platform_services.*` now owns the concrete Apple
   `PlatformServices` implementation plus the `create_apple_platform_services()`
   factory instead of leaving the live Apple execution surface inside

docs/modernization/tasks.md

@@ -52,8 +52,10 @@ Completed, blocked, and superseded task history moved to
     `src/platform_apple/apple_platform_services.*`, and the live Apple
     `PlatformServices` surface now binds directly from those Apple-owned files,
     and Android now also binds directly from
-    `src/platform_android/android_platform_services.*`, but the broader
+    `src/platform_android/android_platform_services.*`, and Linux now also
-    non-Windows fallback adapter still exists for Linux/Web
+    binds directly from `src/platform_linux/linux_platform_services.*`, but the
+    broader non-Windows fallback adapter still exists for Web plus generic
+    fallback policy
   - `platform_legacy` is still part of the live app shell
 - The app runtime boundary is not finished:
   - render/UI queues are static `App` state
@@ -81,6 +83,18 @@ Completed, blocked, and superseded task history moved to
   the queue is now ordered by code movement instead.
 
 Current slice:
+- `src/platform_linux/linux_platform_services.*` now owns the concrete Linux
+  `PlatformServices` implementation and `create_platform_services(...)`
+  instead of leaving the live Linux execution surface in `platform_legacy`.
+- `linux/src/main.cpp` now binds that owned Linux `PlatformServices` instance
+  into `App` directly at the Linux entrypoint.
+- The touched Linux storage-path setup, GLFW render-context acquire/present,
+  app-close dispatch, default render-target binding, desktop file picking, and
+  FPS reporting now route through `src/platform_linux/linux_platform_services.*`
+  instead of the cross-platform fallback adapter.
+- `src/platform_legacy/legacy_platform_services.*` no longer carries the
+  touched Linux method branches, so the retained fallback adapter is narrower
+  again and now focused on the Web path plus generic fallback policy.
 - `src/platform_android/android_platform_services.*` now owns the concrete
   Android `PlatformServices` implementation and `create_platform_services()`
   instead of leaving the live Android execution surface in
@@ -93,8 +107,7 @@ Current slice:
   cross-platform fallback adapter.
 - `src/platform_legacy/legacy_platform_services.*` no longer carries the
   Android bridge/configuration surface or the touched Android method branches,
-  so the retained fallback adapter is narrower again and now focused on the
+  so the retained fallback adapter was narrowed again before the Linux cut.
-  Linux/Web path plus generic fallback policy.
 - `src/platform_apple/apple_platform_services.*` now owns the concrete Apple
   `PlatformServices` implementation plus the `create_apple_platform_services()`
   factory instead of leaving the live Apple execution surface in

linux/CMakeLists.txt

@@ -43,6 +43,7 @@ add_executable(panopainter
 	../src/app_layout.cpp
 	../src/app_shaders.cpp
     ../src/app_vr.cpp
+	../src/platform_linux/linux_platform_services.cpp
 	../src/brush.cpp
 	../src/canvas.cpp
 	../src/canvas_layer.cpp

linux/src/main.cpp

@@ -3,42 +3,11 @@
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
 #include <app.h>
-#include <platform_legacy/legacy_platform_state.h>
+#include <platform_linux/linux_platform_services.h>
-#include <platform_legacy/legacy_platform_services.h>
-#include <libgen.h>
-#include <pwd.h>
-#include <unistd.h>
 
 static App app;
 glm::vec2 g_cursor_pos;
 
-int mkpath(const std::string& dir, mode_t mode = DEFFILEMODE)
-{
-    struct stat sb;
-
-    if (dir.empty()) {
-        errno = EINVAL;
-        return 1;
-    }
-
-    if (!stat(dir.c_str(), &sb))
-        return 0;
-
-    mkpath(dirname(strdupa(dir.c_str())), mode);
-
-    int ret = mkdir(dir.c_str(), mode);
-    chmod(dir.c_str(), S_IRWXU);
-    if (ret != 0)
-        LOG("mkdir failed with error %d on %s", errno, dir.c_str());
-    return ret;
-}
-
-std::string linux_home_path()
-{
-    struct passwd *pw = getpwuid(getuid());
-    return pw->pw_dir;
-}
-
 void error_log(int code, const char * s)
 {
     printf("glfw error: %s", s);
@@ -67,12 +36,10 @@ int main(int argc, char** args)
     pp::platform::linux_desktop::set_fps_title_callback([wnd](std::string title) {
         glfwSetWindowTitle(wnd, title.c_str());
     });
-    auto platform_services = pp::platform::legacy::create_platform_services({
+    auto platform_services = pp::platform::linux_desktop::create_platform_services({
-        .glfw_shell = {
+        .acquire_render_context = [wnd] { glfwMakeContextCurrent(wnd); },
-            .acquire_render_context = [wnd] { glfwMakeContextCurrent(wnd); },
+        .present_render_context = [wnd] { glfwSwapBuffers(wnd); },
-            .present_render_context = [wnd] { glfwSwapBuffers(wnd); },
+        .request_app_close = [wnd] { glfwSetWindowShouldClose(wnd, GLFW_TRUE); },
-            .request_app_close = [wnd] { glfwSetWindowShouldClose(wnd, GLFW_TRUE); },
-        },
     });
 
     glfwSetCursorPosCallback(wnd, [](GLFWwindow* wnd, double x, double y){

src/platform_legacy/legacy_platform_services.cpp

@@ -9,12 +9,7 @@
 #include "platform_api/platform_policy.h"
 #include "renderer_gl/opengl_capabilities.h"
 
-#ifdef __LINUX__
+#ifdef __WEB__
-#include <tinyfiledialogs.h>
-#include "platform_linux/linux_platform_services.h"
-std::string linux_home_path();
-int mkpath(const std::string& dir, mode_t mode = DEFFILEMODE);
-#elif __WEB__
 void webgl_pick_file(std::function<void(std::string)> callback);
 void webgl_pick_file_save(
     const std::string& path,
@@ -37,21 +32,7 @@ public:
 
     [[nodiscard]] pp::platform::PlatformStoragePaths prepare_storage_paths() override
     {
-#if __LINUX__
+#if __WEB__
-        const std::string data_path = linux_home_path() + "/PanoPainter";
-        mkpath(data_path + "/brushes");
-        mkpath(data_path + "/brushes/thumbs");
-        mkpath(data_path + "/patterns");
-        mkpath(data_path + "/patterns/thumbs");
-        mkpath(data_path + "/settings");
-        mkpath(data_path + "/frames");
-        return {
-            data_path,
-            data_path,
-            data_path + "/frames",
-            {},
-        };
-#elif __WEB__
         const std::string data_path = "/PanoPainter";
         mkdir(data_path.c_str(), 0777);
         mkdir((data_path + "/brushes").c_str(), 0777);
@@ -111,7 +92,7 @@ public:
 
     void acquire_render_context() override
     {
-#if __LINUX__ || __WEB__
+#if __WEB__
         invoke_legacy_glfw_shell_callback(glfw_shell_.acquire_render_context);
 #endif
     }
@@ -122,7 +103,7 @@ public:
 
     void present_render_context() override
     {
-#if __LINUX__ || __WEB__
+#if __WEB__
         invoke_legacy_glfw_shell_callback(glfw_shell_.present_render_context);
 #endif
     }
@@ -223,19 +204,12 @@ public:
 
     void report_rendered_frames(int frames) override
     {
-#ifdef __LINUX__
-        pp::platform::linux_desktop::report_rendered_frames(frames);
-#else
         (void)frames;
-#endif
     }
 
     void pick_image(pp::platform::PickedPathCallback callback) override
     {
-#ifdef __LINUX__
+#ifdef __WEB__
-        if (auto p = tinyfd_openFileDialog("Open File", "", 0, nullptr, nullptr, false))
-            invoke_picked_path_if_selected(p, callback);
-#elif __WEB__
         webgl_pick_file(callback);
 #else
         (void)callback;
@@ -244,10 +218,7 @@ public:
 
     void pick_file(std::vector<std::string> file_types, pp::platform::PickedPathCallback callback) override
     {
-#ifdef __LINUX__
+#ifdef __WEB__
-        if (auto p = tinyfd_openFileDialog("Open File", "", 0, nullptr, nullptr, false))
-            invoke_picked_path_if_selected(p, callback);
-#elif __WEB__
         webgl_pick_file(callback);
 #else
         (void)file_types;
@@ -364,7 +335,7 @@ public:
 
     void request_app_close() override
     {
-#ifdef __LINUX__
+#if __WEB__
         invoke_legacy_glfw_shell_callback(glfw_shell_.request_app_close);
 #endif
     }

src/platform_linux/linux_platform_services.cpp

@@ -1,9 +1,358 @@
 #include "platform_linux/linux_platform_services.h"
 
-#ifdef __LINUX__
+#include <memory>
-#include <string>
 #include <utility>
 
+#ifdef __LINUX__
+#include "legacy_ui_gl_dispatch.h"
+#include "log.h"
+#include "platform_api/network_tls_policy.h"
+#include "platform_api/platform_policy.h"
+#include "renderer_gl/opengl_capabilities.h"
+
+#include <cerrno>
+#include <libgen.h>
+#include <pwd.h>
+#include <string>
+#include <sys/stat.h>
+#include <tinyfiledialogs.h>
+#include <unistd.h>
+#endif
+
+#ifdef __LINUX__
+namespace {
+
+constexpr auto kPlatformFamily = pp::platform::PlatformFamily::linux_desktop;
+
+std::string linux_home_path()
+{
+    struct passwd* pw = getpwuid(getuid());
+    return pw->pw_dir;
+}
+
+int mkpath(const std::string& dir, mode_t mode = DEFFILEMODE)
+{
+    struct stat sb;
+
+    if (dir.empty())
+    {
+        errno = EINVAL;
+        return 1;
+    }
+
+    if (!stat(dir.c_str(), &sb))
+        return 0;
+
+    mkpath(dirname(strdupa(dir.c_str())), mode);
+
+    int ret = mkdir(dir.c_str(), mode);
+    chmod(dir.c_str(), S_IRWXU);
+    if (ret != 0)
+        LOG("mkdir failed with error %d on %s", errno, dir.c_str());
+    return ret;
+}
+
+void invoke_picked_path_if_selected(
+    const char* path,
+    const pp::platform::PickedPathCallback& callback)
+{
+    if (!path || !callback)
+        return;
+    callback(path);
+}
+
+class LinuxPlatformServices final : public pp::platform::PlatformServices {
+public:
+    explicit LinuxPlatformServices(pp::platform::linux_desktop::LinuxPlatformBridge bridge)
+        : bridge_(std::move(bridge))
+    {
+    }
+
+    [[nodiscard]] PlatformStoragePaths prepare_storage_paths() override
+    {
+        const std::string data_path = linux_home_path() + "/PanoPainter";
+        mkpath(data_path + "/brushes");
+        mkpath(data_path + "/brushes/thumbs");
+        mkpath(data_path + "/patterns");
+        mkpath(data_path + "/patterns/thumbs");
+        mkpath(data_path + "/settings");
+        mkpath(data_path + "/frames");
+        return {
+            data_path,
+            data_path,
+            data_path + "/frames",
+            {},
+        };
+    }
+
+    void log_stacktrace() override
+    {
+    }
+
+    void trigger_crash_test() override
+    {
+    }
+
+    [[nodiscard]] std::string clipboard_text() override
+    {
+        return {};
+    }
+
+    [[nodiscard]] bool set_clipboard_text(std::string_view text) override
+    {
+        (void)text;
+        return false;
+    }
+
+    void set_cursor_visible(bool visible) override
+    {
+        (void)visible;
+    }
+
+    void set_virtual_keyboard_visible(bool visible) override
+    {
+        (void)visible;
+    }
+
+    void attach_ui_thread() override
+    {
+    }
+
+    void detach_ui_thread() override
+    {
+    }
+
+    void acquire_render_context() override
+    {
+        invoke_shell_callback(bridge_.acquire_render_context);
+    }
+
+    void release_render_context() override
+    {
+    }
+
+    void present_render_context() override
+    {
+        invoke_shell_callback(bridge_.present_render_context);
+    }
+
+    void bind_default_render_target() override
+    {
+        pp::legacy::ui_gl::bind_opengl_framebuffer(
+            pp::renderer::gl::framebuffer_target(),
+            pp::renderer::gl::default_framebuffer_id());
+    }
+
+    void bind_main_render_target() override
+    {
+        bind_default_render_target();
+    }
+
+    void apply_render_platform_hints() override
+    {
+    }
+
+    void install_render_debug_callback() override
+    {
+    }
+
+    void begin_render_capture_frame() override
+    {
+    }
+
+    void end_render_capture_frame() override
+    {
+    }
+
+    [[nodiscard]] bool deletes_recorded_files_on_clear() override
+    {
+        return platform_deletes_recorded_files_on_clear(kPlatformFamily);
+    }
+
+    void clear_recorded_files(std::string_view recording_path) override
+    {
+        (void)recording_path;
+    }
+
+    void publish_exported_image(std::string_view path) override
+    {
+        (void)path;
+    }
+
+    void flush_persistent_storage() override
+    {
+    }
+
+    [[nodiscard]] std::vector<std::string> document_browse_roots(
+        std::string_view work_path,
+        std::string_view data_path) override
+    {
+        return platform_document_browse_roots(kPlatformFamily, work_path, data_path);
+    }
+
+    void save_ui_state() override
+    {
+    }
+
+    [[nodiscard]] bool enables_live_asset_reloading() override
+    {
+        return platform_enables_live_asset_reloading(kPlatformFamily);
+    }
+
+    void update_platform_frame(float delta_time_seconds) override
+    {
+        (void)delta_time_seconds;
+    }
+
+    void report_rendered_frames(int frames) override
+    {
+        pp::platform::linux_desktop::report_rendered_frames(frames);
+    }
+
+    void display_file(std::string_view path) override
+    {
+        (void)path;
+    }
+
+    void share_file(std::string_view path) override
+    {
+        (void)path;
+    }
+
+    void request_app_close() override
+    {
+        invoke_shell_callback(bridge_.request_app_close);
+    }
+
+    [[nodiscard]] bool start_vr_mode() override
+    {
+        return false;
+    }
+
+    void stop_vr_mode() override
+    {
+    }
+
+    void pick_image(PickedPathCallback callback) override
+    {
+        if (auto* path = tinyfd_openFileDialog("Open File", "", 0, nullptr, nullptr, false))
+            invoke_picked_path_if_selected(path, callback);
+    }
+
+    void pick_file(std::vector<std::string> file_types, PickedPathCallback callback) override
+    {
+        (void)file_types;
+        if (auto* path = tinyfd_openFileDialog("Open File", "", 0, nullptr, nullptr, false))
+            invoke_picked_path_if_selected(path, callback);
+    }
+
+    void pick_save_file(std::vector<std::string> file_types, PickedPathCallback callback) override
+    {
+        (void)file_types;
+        (void)callback;
+    }
+
+    void pick_directory(PickedPathCallback callback) override
+    {
+        (void)callback;
+    }
+
+    [[nodiscard]] bool supports_working_directory_picker() override
+    {
+        return platform_supports_working_directory_picker(kPlatformFamily);
+    }
+
+    [[nodiscard]] std::string format_working_directory_path(std::string_view path) override
+    {
+        return std::string(path);
+    }
+
+    [[nodiscard]] bool uses_prepared_file_writes() override
+    {
+        return platform_uses_prepared_file_writes(kPlatformFamily);
+    }
+
+    [[nodiscard]] bool uses_work_directory_document_export_collections() override
+    {
+        return platform_uses_work_directory_document_export_collections(kPlatformFamily);
+    }
+
+    [[nodiscard]] bool disables_network_tls_verification() override
+    {
+        return default_disables_network_tls_verification();
+    }
+
+    [[nodiscard]] bool uses_ppbr_export_data_directory_override() override
+    {
+        return platform_uses_ppbr_export_data_directory_override(kPlatformFamily);
+    }
+
+    [[nodiscard]] bool supports_sonarpen() override
+    {
+        return platform_supports_sonarpen(kPlatformFamily);
+    }
+
+    void start_sonarpen() override
+    {
+    }
+
+    [[nodiscard]] int default_canvas_resolution() override
+    {
+        return platform_default_canvas_resolution(kPlatformFamily);
+    }
+
+    [[nodiscard]] bool draws_canvas_tip_for_pointer(
+        bool is_mouse,
+        bool is_stylus,
+        bool is_left_button_release) override
+    {
+        return platform_draws_canvas_tip_for_pointer(
+            kPlatformFamily,
+            is_mouse,
+            is_stylus,
+            is_left_button_release);
+    }
+
+    [[nodiscard]] float adjust_canvas_input_pressure(float pressure) override
+    {
+        return pressure;
+    }
+
+    [[nodiscard]] PreparedFileTarget prepare_writable_file(
+        std::string_view type,
+        std::string_view default_name,
+        std::string_view data_path,
+        std::string_view temporary_path) override
+    {
+        return plan_platform_writable_file(
+            kPlatformFamily,
+            type,
+            default_name,
+            data_path,
+            temporary_path);
+    }
+
+    void save_prepared_file(
+        std::string_view path,
+        std::string_view suggested_name,
+        PreparedFileCallback callback) override
+    {
+        (void)suggested_name;
+        callback(std::string(path), false);
+    }
+
+private:
+    static void invoke_shell_callback(const std::function<void()>& callback)
+    {
+        if (callback)
+            callback();
+    }
+
+    pp::platform::linux_desktop::LinuxPlatformBridge bridge_;
+};
+
+}
+
 namespace pp::platform::linux_desktop {
 namespace {
 
@@ -19,6 +368,12 @@ void linux_update_fps(int frames)
 
 }
 
+std::unique_ptr<pp::platform::PlatformServices> create_platform_services(
+    LinuxPlatformBridge bridge)
+{
+    return std::make_unique<LinuxPlatformServices>(std::move(bridge));
+}
+
 void set_fps_title_callback(std::function<void(std::string)> callback)
 {
     g_fps_title_callback = std::move(callback);
@@ -33,6 +388,13 @@ void report_rendered_frames(int frames)
 #else
 namespace pp::platform::linux_desktop {
 
+std::unique_ptr<pp::platform::PlatformServices> create_platform_services(
+    LinuxPlatformBridge bridge)
+{
+    (void)bridge;
+    return nullptr;
+}
+
 void set_fps_title_callback(std::function<void(std::string)> callback)
 {
     (void)callback;

src/platform_linux/linux_platform_services.h

@@ -1,10 +1,22 @@
 #pragma once
 
+#include "platform_api/platform_services.h"
+
 #include <functional>
+#include <memory>
 #include <string>
 
 namespace pp::platform::linux_desktop {
 
+struct LinuxPlatformBridge {
+    std::function<void()> acquire_render_context;
+    std::function<void()> present_render_context;
+    std::function<void()> request_app_close;
+};
+
+[[nodiscard]] std::unique_ptr<pp::platform::PlatformServices> create_platform_services(
+    LinuxPlatformBridge bridge = {});
+
 void set_fps_title_callback(std::function<void(std::string)> callback);
 void report_rendered_frames(int frames);