Implement posix app loading (#643)

- Added POSIX desktop support for SDK builds, application packaging, and integration testing.
- Added POSIX filesystem partitions and improved application path handling.
- Added simulator support for loading and running applications dynamically.
- Improved simulator task stack handling and display startup reliability.
- Improved simulator display scaling, resizing, high-DPI support, and pointer accuracy.
- Fixed LVGL timers and input polling on POSIX. (fixes simulator with Linux on some Intel graphics platforms)
- Standardized data paths across platforms.
- Logging now works via separate task: this allows apps to write to log without it affecting their stdout (for apps that output text as relevant date for other apps, like the File Selection app)
- Fixes for app stdio

Modules/app-module/source/io.cpp

@@ -7,7 +7,7 @@
 
 #include <cerrno>
 
-#ifdef ESP_PLATFORM
+#if defined(TT_APP_IO_WRAPS_STDIO)
 extern "C" {
 ssize_t __real_read(int fd, void* buffer, size_t size);
 ssize_t __real_write(int fd, const void* buffer, size_t size);
@@ -56,7 +56,7 @@ ssize_t app_io_read(int fd, void* buffer, size_t size) {
         errno = EBADF;
         return -1;
     }
-#ifdef ESP_PLATFORM
+#if defined(TT_APP_IO_WRAPS_STDIO)
     return __real_read(fd, buffer, size);
 #else
     return ::read(fd, buffer, size);
@@ -71,13 +71,25 @@ ssize_t app_io_write(int fd, const void* buffer, size_t size) {
         if (file.ops->release != nullptr) {
             file.ops->release(file.object);
         }
+        // Tee to the real fd too: a bound stream only exists because a parent explicitly asked
+        // to capture this app instance's own output (see AppStreamBinding), but generic code
+        // running on that same instance's thread - most commonly the platform's own logging
+        // (LOG_I/etc, which calls write() the same as anything else) - has no way to know its
+        // output is currently being intercepted. Without this, a log line emitted while any app
+        // instance has its stdout captured would vanish from the console entirely instead of
+        // just also being visible to the capturing parent.
+#if defined(TT_APP_IO_WRAPS_STDIO)
+        __real_write(fd, buffer, size);
+#else
+        ::write(fd, buffer, size);
+#endif
         return result;
     }
     if (table != nullptr && app_fd_table_is_app_owned(table, fd)) {
         errno = EBADF;
         return -1;
     }
-#ifdef ESP_PLATFORM
+#if defined(TT_APP_IO_WRAPS_STDIO)
     return __real_write(fd, buffer, size);
 #else
     return ::write(fd, buffer, size);
@@ -96,7 +108,7 @@ int app_io_close(int fd) {
             return -1;
         }
     }
-#ifdef ESP_PLATFORM
+#if defined(TT_APP_IO_WRAPS_STDIO)
     return __real_close(fd);
 #else
     return ::close(fd);

Modules/app-module/source/manager.cpp

@@ -178,6 +178,10 @@ error_t app_manager_start_with_streams(const char* id, const AppStreamBinding* b
     return start_internal(id, 0, 0, nullptr, bindings, binding_count, out_app_instance_id);
 }
 
+error_t app_manager_start_for_result_with_streams(const char* id, AppInstanceId parent_instance_id, int argc, const char* const argv[], const AppStreamBinding* bindings, size_t binding_count, AppInstanceId* out_app_instance_id) {
+    return start_internal(id, parent_instance_id, argc, copy_arguments(argc, argv), bindings, binding_count, out_app_instance_id);
+}
+
 error_t app_manager_stop(AppInstanceId app_instance_id) {
     return app_scheduler_stop(app_instance_id, pdMS_TO_TICKS(2000));
 }

Modules/app-module/source/module.cpp

@@ -38,6 +38,7 @@ static const ModuleSymbol SYMBOLS[] = {
     DEFINE_MODULE_SYMBOL(app_manager_start_with_parameters),
     DEFINE_MODULE_SYMBOL(app_manager_start_for_result),
     DEFINE_MODULE_SYMBOL(app_manager_start_with_streams),
+    DEFINE_MODULE_SYMBOL(app_manager_start_for_result_with_streams),
     DEFINE_MODULE_SYMBOL(app_manager_stop),
     DEFINE_MODULE_SYMBOL(app_manager_get_state),
     DEFINE_MODULE_SYMBOL(app_manager_find_manifest),

Modules/app-module/source/scheduler.cpp

@@ -199,12 +199,19 @@ void app_task_main(void* context) {
     check(pvTaskGetThreadLocalStoragePointer(nullptr, APP_INSTANCE_ID_THREAD_SLOT_INDEX) == nullptr);
     vTaskSetThreadLocalStoragePointer(nullptr, APP_INSTANCE_ID_THREAD_SLOT_INDEX, reinterpret_cast<void*>(static_cast<uintptr_t>(ctx->app_instance_id)));
 
+    // Debug logging so it's invisible by default
+    // When logging happens, it can distort the application stdout, which breaks apps that use
+    // stdout to output important information, such as the file selection dialog app.
     LOG_I(TAG, "[instance %lu] Task started", ctx->app_instance_id);
 
     set_state(ctx->app_instance_id, APP_INSTANCE_STATE_ACTIVE);
 
     int32_t result = ctx->loader->run(ctx->runtime, ctx->app_instance_id, ctx->argc, ctx->argv);
 
+    // The platform might buffer stdout (e.g. esp-idf with newlib)
+    // Do a manual flush to ensure data has been written:
+    fflush(stdout);
+
     vTaskSetThreadLocalStoragePointer(nullptr, APP_INSTANCE_ID_THREAD_SLOT_INDEX, nullptr);
 
     ctx->loader->unload(ctx->runtime);