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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "flutter/shell/platform/linux/public/flutter_linux/fl_event_channel.h"
#include <gmodule.h>
#include "flutter/shell/platform/linux/fl_method_codec_private.h"
static constexpr char kListenMethod[] = "listen";
static constexpr char kCancelMethod[] = "cancel";
static constexpr char kEventRequestError[] = "error";
struct _FlEventChannel {
GObject parent_instance;
// Messenger to communicate on.
FlBinaryMessenger* messenger;
// Channel name.
gchar* name;
// Codec to en/decode messages.
FlMethodCodec* codec;
// Function called when the stream is listened to / cancelled.
FlEventChannelHandler listen_handler;
FlEventChannelHandler cancel_handler;
gpointer handler_data;
GDestroyNotify handler_data_destroy_notify;
};
struct _FlEventChannelResponseHandle {
GObject parent_instance;
FlBinaryMessengerResponseHandle* response_handle;
};
// Added here to stop the compiler from optimizing this function away.
G_MODULE_EXPORT GType fl_event_channel_get_type();
G_DEFINE_TYPE(FlEventChannel, fl_event_channel, G_TYPE_OBJECT)
// Handle method calls from the Dart side of the channel.
static FlMethodErrorResponse* handle_method_call(FlEventChannel* self,
const gchar* name,
FlValue* args) {
FlEventChannelHandler handler;
if (g_strcmp0(name, kListenMethod) == 0) {
handler = self->listen_handler;
} else if (g_strcmp0(name, kCancelMethod) == 0) {
handler = self->cancel_handler;
} else {
g_autofree gchar* message =
g_strdup_printf("Unknown event channel request '%s'", name);
return fl_method_error_response_new(kEventRequestError, message, nullptr);
}
// If not handled, just accept requests.
if (handler == nullptr) {
return nullptr;
}
return handler(self, args, self->handler_data);
}
// Called when a binary message is received on this channel.
static void message_cb(FlBinaryMessenger* messenger,
const gchar* channel,
GBytes* message,
FlBinaryMessengerResponseHandle* response_handle,
gpointer user_data) {
FlEventChannel* self = FL_EVENT_CHANNEL(user_data);
g_autofree gchar* name = nullptr;
g_autoptr(GError) error = nullptr;
g_autoptr(FlValue) args = nullptr;
if (!fl_method_codec_decode_method_call(self->codec, message, &name, &args,
&error)) {
g_warning("Failed to decode message on event channel %s: %s", self->name,
error->message);
fl_binary_messenger_send_response(messenger, response_handle, nullptr,
nullptr);
return;
}
g_autoptr(FlMethodErrorResponse) response =
handle_method_call(self, name, args);
g_autoptr(GBytes) data = nullptr;
if (response == nullptr) {
g_autoptr(GError) codec_error = nullptr;
data = fl_method_codec_encode_success_envelope(self->codec, nullptr,
&codec_error);
if (data == nullptr) {
g_warning("Failed to encode event channel %s success response: %s",
self->name, codec_error->message);
}
} else {
g_autoptr(GError) codec_error = nullptr;
data = fl_method_codec_encode_error_envelope(
self->codec, fl_method_error_response_get_code(response),
fl_method_error_response_get_message(response),
fl_method_error_response_get_details(response), &codec_error);
if (data == nullptr) {
g_warning("Failed to encode event channel %s error response: %s",
self->name, codec_error->message);
}
}
if (!fl_binary_messenger_send_response(messenger, response_handle, data,
&error)) {
g_warning("Failed to send event channel response: %s", error->message);
}
}
// Removes handlers and their associated data.
static void remove_handlers(FlEventChannel* self) {
if (self->handler_data_destroy_notify != nullptr) {
self->handler_data_destroy_notify(self->handler_data);
}
self->listen_handler = nullptr;
self->cancel_handler = nullptr;
self->handler_data = nullptr;
self->handler_data_destroy_notify = nullptr;
}
// Called when the channel handler is closed.
static void channel_closed_cb(gpointer user_data) {
g_autoptr(FlEventChannel) self = FL_EVENT_CHANNEL(user_data);
remove_handlers(self);
}
static void fl_event_channel_dispose(GObject* object) {
FlEventChannel* self = FL_EVENT_CHANNEL(object);
if (self->messenger != nullptr) {
fl_binary_messenger_set_message_handler_on_channel(
self->messenger, self->name, nullptr, nullptr, nullptr);
}
g_clear_object(&self->messenger);
g_clear_pointer(&self->name, g_free);
g_clear_object(&self->codec);
remove_handlers(self);
G_OBJECT_CLASS(fl_event_channel_parent_class)->dispose(object);
}
static void fl_event_channel_class_init(FlEventChannelClass* klass) {
G_OBJECT_CLASS(klass)->dispose = fl_event_channel_dispose;
}
static void fl_event_channel_init(FlEventChannel* self) {}
G_MODULE_EXPORT FlEventChannel* fl_event_channel_new(
FlBinaryMessenger* messenger,
const gchar* name,
FlMethodCodec* codec) {
g_return_val_if_fail(FL_IS_BINARY_MESSENGER(messenger), nullptr);
g_return_val_if_fail(name != nullptr, nullptr);
g_return_val_if_fail(FL_IS_METHOD_CODEC(codec), nullptr);
FlEventChannel* self =
FL_EVENT_CHANNEL(g_object_new(fl_event_channel_get_type(), nullptr));
self->messenger = FL_BINARY_MESSENGER(g_object_ref(messenger));
self->name = g_strdup(name);
self->codec = FL_METHOD_CODEC(g_object_ref(codec));
fl_binary_messenger_set_message_handler_on_channel(
self->messenger, self->name, message_cb, g_object_ref(self),
channel_closed_cb);
return self;
}
G_MODULE_EXPORT void fl_event_channel_set_stream_handlers(
FlEventChannel* self,
FlEventChannelHandler listen_handler,
FlEventChannelHandler cancel_handler,
gpointer user_data,
GDestroyNotify destroy_notify) {
g_return_if_fail(FL_IS_EVENT_CHANNEL(self));
remove_handlers(self);
self->listen_handler = listen_handler;
self->cancel_handler = cancel_handler;
self->handler_data = user_data;
self->handler_data_destroy_notify = destroy_notify;
}
G_MODULE_EXPORT gboolean fl_event_channel_send(FlEventChannel* self,
FlValue* event,
GCancellable* cancellable,
GError** error) {
g_return_val_if_fail(FL_IS_EVENT_CHANNEL(self), FALSE);
g_return_val_if_fail(event != nullptr, FALSE);
g_autoptr(GBytes) data =
fl_method_codec_encode_success_envelope(self->codec, event, error);
if (data == nullptr) {
return FALSE;
}
fl_binary_messenger_send_on_channel(self->messenger, self->name, data,
cancellable, nullptr, nullptr);
return TRUE;
}
G_MODULE_EXPORT gboolean fl_event_channel_send_error(FlEventChannel* self,
const gchar* code,
const gchar* message,
FlValue* details,
GCancellable* cancellable,
GError** error) {
g_return_val_if_fail(FL_IS_EVENT_CHANNEL(self), FALSE);
g_return_val_if_fail(code != nullptr, FALSE);
g_return_val_if_fail(message != nullptr, FALSE);
g_autoptr(GBytes) data = fl_method_codec_encode_error_envelope(
self->codec, code, message, details, error);
if (data == nullptr) {
return FALSE;
}
fl_binary_messenger_send_on_channel(self->messenger, self->name, data,
cancellable, nullptr, nullptr);
return TRUE;
}
G_MODULE_EXPORT gboolean
fl_event_channel_send_end_of_stream(FlEventChannel* self,
GCancellable* cancellable,
GError** error) {
g_return_val_if_fail(FL_IS_EVENT_CHANNEL(self), FALSE);
fl_binary_messenger_send_on_channel(self->messenger, self->name, nullptr,
cancellable, nullptr, nullptr);
return TRUE;
}