Add visibility/export annotations

Adds export macros, and annotations for all symbols that should be
public.

Switches the default for shared library builds on Linux to
visibility=hidden so that missing annotations will be caught on both
platforms, rather than just Windows.

Fixes issue google#208

Author: stuartmorgan-g

build/BUILD.gn

@@ -38,6 +38,8 @@ config("shared_library_defaults") {
     cflags = [
       "-shared",
       "-fPIC",
+      # Default to hidden for consistency with Windows builds.
+      "-fvisibility=hidden",
     ]
   }
 }

library/BUILD.gn

@@ -47,6 +47,7 @@ published_shared_library("flutter_embedder") {
     public += [
       "include/flutter_desktop_embedding/binary_messenger.h",
       "include/flutter_desktop_embedding/engine_method_result.h",
+      "include/flutter_desktop_embedding/fde_export.h",
       "include/flutter_desktop_embedding/json_method_codec.h",
       "include/flutter_desktop_embedding/method_call.h",
       "include/flutter_desktop_embedding/method_channel.h",
@@ -60,6 +61,10 @@ published_shared_library("flutter_embedder") {
     ":fetch_flutter_engine",
   ]
 
+  defines = [
+    "FLUTTER_DESKTOP_EMBEDDING_IMPL",
+  ]
+
   public_header_subdir = "flutter_desktop_embedding"
 
   public_configs = [

library/include/flutter_desktop_embedding/binary_messenger.h

@@ -17,6 +17,8 @@
 #include <functional>
 #include <string>
 
+#include "fde_export.h"
+
 // TODO: Consider adding absl as a dependency and using absl::Span for all of
 // the message/message_size pairs.
 namespace flutter_desktop_embedding {
@@ -36,7 +38,7 @@ typedef std::function<void(const uint8_t *message, const size_t message_size,
 
 // A protocol for a class that handles communication of binary data on named
 // channels to and from the Flutter engine.
-class BinaryMessenger {
+class FDE_EXPORT BinaryMessenger {
  public:
   // Sends a binary message to the Flutter side on the specified channel,
   // expecting no reply.

library/include/flutter_desktop_embedding/engine_method_result.h

@@ -19,6 +19,7 @@
 #include <vector>
 
 #include "binary_messenger.h"
+#include "fde_export.h"
 #include "method_codec.h"
 #include "method_result.h"
 
@@ -28,7 +29,7 @@ namespace internal {
 // Manages the one-time sending of response data. This is an internal helper
 // class for EngineMethodResult, separated out since the implementation doesn't
 // vary based on the template type.
-class ReplyManager {
+class FDE_EXPORT ReplyManager {
  public:
   ReplyManager(BinaryReply reply_handler_);
   ~ReplyManager();
@@ -50,7 +51,7 @@ class ReplyManager {
 // Implemention of MethodResult that sends a response to the Flutter engine
 // exactly once, encoded using a given codec.
 template <typename T>
-class EngineMethodResult : public MethodResult<T> {
+class FDE_EXPORT EngineMethodResult : public MethodResult<T> {
  public:
   // Creates a result object that will send results to |reply_handler|, encoded
   // using |codec|. The |codec| pointer must remain valid for as long as this

library/include/flutter_desktop_embedding/fde_export.h

@@ -0,0 +1,37 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FDE_EXPORT_H_
+#define LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FDE_EXPORT_H_
+
+#ifdef FLUTTER_DESKTOP_EMBEDDING_IMPL
+// Add visibiilty/export annotations when building the library.
+
+#ifdef _WIN32
+#define FDE_EXPORT __declspec(dllexport)
+#else
+#define FDE_EXPORT __attribute__((visibility("default")))
+#endif
+
+#else
+
+// Add import annotations when consuming the library.
+#ifdef _WIN32
+#define FDE_EXPORT __declspec(dllimport)
+#else
+#define FDE_EXPORT
+#endif
+
+#endif
+
+#endif  // LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FDE_EXPORT_H_

library/include/flutter_desktop_embedding/glfw/embedder.h

@@ -27,8 +27,10 @@
 #include <GLFW/glfw3.h>
 
 #ifdef USE_FLATTENED_INCLUDES
+#include "fde_export.h"
 #include "plugin_registrar.h"
 #else
+#include "../fde_export.h"
 #include "../plugin_registrar.h"
 #endif
 
@@ -37,12 +39,12 @@ namespace flutter_desktop_embedding {
 // Calls glfwInit()
 //
 // glfwInit() must be called in the same library as glfwCreateWindow()
-bool FlutterInit();
+FDE_EXPORT bool FlutterInit();
 
 // Calls glfwTerminate()
 //
 // glfwTerminate() must be called in the same library as glfwCreateWindow()
-void FlutterTerminate();
+FDE_EXPORT void FlutterTerminate();
 
 // Creates a GLFW Window running a Flutter Application.
 //
@@ -54,12 +56,11 @@ void FlutterTerminate();
 //
 // Returns a null pointer in the event of an error. The caller owns the pointer
 // when it is non-null.
-GLFWwindow *CreateFlutterWindow(size_t initial_width, size_t initial_height,
-                                const std::string &main_path,
-                                const std::string &assets_path,
-                                const std::string &packages_path,
-                                const std::string &icu_data_path,
-                                const std::vector<std::string> &arguments);
+FDE_EXPORT GLFWwindow *CreateFlutterWindow(
+    size_t initial_width, size_t initial_height, const std::string &main_path,
+    const std::string &assets_path, const std::string &packages_path,
+    const std::string &icu_data_path,
+    const std::vector<std::string> &arguments);
 
 // Creates a GLFW Window running a Flutter Application in snapshot mode.
 //
@@ -74,7 +75,7 @@ GLFWwindow *CreateFlutterWindow(size_t initial_width, size_t initial_height,
 //
 // Returns a null pointer in the event of an error. The caller owns the pointer
 // when it is non-null.
-GLFWwindow *CreateFlutterWindowInSnapshotMode(
+FDE_EXPORT GLFWwindow *CreateFlutterWindowInSnapshotMode(
     size_t initial_width, size_t initial_height, const std::string &assets_path,
     const std::string &icu_data_path,
     const std::vector<std::string> &arguments);
@@ -84,8 +85,8 @@ GLFWwindow *CreateFlutterWindowInSnapshotMode(
 //
 // The name must be unique across the application, so the recommended approach
 // is to use the fully namespace-qualified name of the plugin class.
-PluginRegistrar *GetRegistrarForPlugin(GLFWwindow *flutter_window,
-                                       const std::string &plugin_name);
+FDE_EXPORT PluginRegistrar *GetRegistrarForPlugin(
+    GLFWwindow *flutter_window, const std::string &plugin_name);
 
 // Loops on flutter window events until termination.
 //
@@ -94,7 +95,7 @@ PluginRegistrar *GetRegistrarForPlugin(GLFWwindow *flutter_window,
 //
 // After this function the user must eventually call FlutterTerminate() if doing
 // cleanup.
-void FlutterWindowLoop(GLFWwindow *flutter_window);
+FDE_EXPORT void FlutterWindowLoop(GLFWwindow *flutter_window);
 
 }  // namespace flutter_desktop_embedding
 

library/include/flutter_desktop_embedding/json_method_codec.h

@@ -16,13 +16,14 @@
 
 #include <json/json.h>
 
+#include "fde_export.h"
 #include "method_call.h"
 #include "method_codec.h"
 
 namespace flutter_desktop_embedding {
 
 // An implementation of MethodCodec that uses JSON strings as the serialization.
-class JsonMethodCodec : public MethodCodec<Json::Value> {
+class FDE_EXPORT JsonMethodCodec : public MethodCodec<Json::Value> {
  public:
   // Returns the shared instance of the codec.
   static const JsonMethodCodec &GetInstance();

library/include/flutter_desktop_embedding/method_call.h

@@ -17,12 +17,14 @@
 #include <memory>
 #include <string>
 
+#include "fde_export.h"
+
 namespace flutter_desktop_embedding {
 
 // An object encapsulating a method call from Flutter whose arguments are of
 // type T.
 template <typename T>
-class MethodCall {
+class FDE_EXPORT MethodCall {
  public:
   // Creates a MethodCall with the given name and arguments.
   explicit MethodCall(const std::string &method_name,

library/include/flutter_desktop_embedding/method_channel.h

@@ -19,6 +19,7 @@
 
 #include "binary_messenger.h"
 #include "engine_method_result.h"
+#include "fde_export.h"
 #include "method_call.h"
 #include "method_codec.h"
 #include "method_result.h"
@@ -36,7 +37,7 @@ using MethodCallHandler = std::function<void(
 // A channel for communicating with the Flutter engine using invocation of
 // asynchronous methods.
 template <typename T>
-class MethodChannel {
+class FDE_EXPORT MethodChannel {
  public:
   // Creates an instance that sends and receives method calls on the channel
   // named |name|, encoded with |codec| and dispatched via |messenger|.

library/include/flutter_desktop_embedding/method_codec.h

@@ -18,14 +18,15 @@
 #include <string>
 #include <vector>
 
+#include "fde_export.h"
 #include "method_call.h"
 
 namespace flutter_desktop_embedding {
 
 // Translates between a binary message and higher-level method call and
 // response/error objects.
 template <typename T>
-class MethodCodec {
+class FDE_EXPORT MethodCodec {
  public:
   MethodCodec() = default;
   virtual ~MethodCodec() = default;

library/include/flutter_desktop_embedding/method_result.h

@@ -16,12 +16,14 @@
 
 #include <string>
 
+#include "fde_export.h"
+
 namespace flutter_desktop_embedding {
 
 // Encapsulates a result sent back to the Flutter engine in response to a
 // MethodCall. Only one method should be called on any given instance.
 template <typename T>
-class MethodResult {
+class FDE_EXPORT MethodResult {
  public:
   MethodResult() = default;
   virtual ~MethodResult() = default;

library/include/flutter_desktop_embedding/plugin_registrar.h

@@ -17,6 +17,7 @@
 #include <memory>
 
 #include "binary_messenger.h"
+#include "fde_export.h"
 
 namespace flutter_desktop_embedding {
 
@@ -27,7 +28,7 @@ class Plugin;
 // Currently this class has very limited functionality, but is expected to
 // expand over time to more closely match the functionality of
 // the Flutter mobile plugin APIs' plugin registrars.
-class PluginRegistrar {
+class FDE_EXPORT PluginRegistrar {
  public:
   virtual ~PluginRegistrar() {}
 
@@ -53,7 +54,7 @@ class PluginRegistrar {
 };
 
 // A plugin that can be registered for ownership by a PluginRegistrar.
-class Plugin {
+class FDE_EXPORT Plugin {
  public:
   virtual ~Plugin() {}
 };

library/linux/Makefile

@@ -22,10 +22,11 @@ ENGINE_UPDATER=$(TOOLS_DIR)/update_flutter_engine
 FLUTTER_DIR=$(shell "$(TOOLS_DIR)/flutter_location")
 LIBRARY_OUT=libflutter_embedder.so
 CXX=g++ -std=c++14
-CXXFLAGS= -Wall -Werror -shared -fPIC \
+CXXFLAGS= -Wall -Werror -shared -fPIC -fvisibility=hidden \
 	-I$(PROJECT_ROOT) \
 	-I$(PROJECT_ROOT)/library/include \
 	-I$(FLUTTER_ENGINE_HEADER_DIR) \
+	-DFLUTTER_DESKTOP_EMBEDDING_IMPL \
 	$(shell pkg-config --cflags gtk+-3.0 epoxy x11 jsoncpp)
 LDFLAGS= -L$(CURDIR) \
 	$(shell pkg-config --libs gtk+-3.0 epoxy x11 jsoncpp) \

plugins/color_panel/BUILD.gn

@@ -30,7 +30,10 @@ published_shared_library("color_panel") {
     ]
   }
 
-  defines = ["USE_FLATTENED_INCLUDES"]
+  defines = [
+    "COLOR_PANEL_PLUGIN_IMPL",
+    "USE_FLATTENED_INCLUDES",
+  ]
 
   deps = [
     "//library:flutter_embedder",

plugins/color_panel/linux/Makefile

@@ -24,9 +24,10 @@ EMBEDDER_LIB_FILE=$(EMBEDDER_LIBRARY_OUT_DIR)/lib$(EMBEDDER_LIB_NAME).so
 COMMON_DIR=$(CURDIR)/../common
 
 CXX=g++ -std=c++14
-CXXFLAGS= -Wall -Werror -shared -fPIC \
+CXXFLAGS= -Wall -Werror -shared -fPIC -fvisibility=hidden \
 	-I$(PROJECT_ROOT) \
 	-I$(EMBEDDER_LIBRARY_HEADER_DIR) \
+	-DCOLOR_PANEL_PLUGIN_IMPL \
 	$(shell pkg-config --cflags gtk+-3.0 jsoncpp)
 LDFLAGS= -L$(EMBEDDER_LIBRARY_OUT_DIR) \
 	$(shell pkg-config --libs gtk+-3.0 jsoncpp) \

plugins/color_panel/linux/include/color_panel/color_panel_plugin.h

@@ -21,10 +21,17 @@
 #include <flutter_desktop_embedding/method_channel.h>
 #include <flutter_desktop_embedding/plugin_registrar.h>
 
+#ifdef COLOR_PANEL_PLUGIN_IMPL
+#define COLOR_PANEL_PLUGIN_EXPORT __attribute__((visibility("default")))
+#else
+#define COLOR_PANEL_PLUGIN_EXPORT
+#endif
+
 namespace plugins_color_panel {
 
 // A plugin for communicating with a native color picker panel.
-class ColorPanelPlugin : public flutter_desktop_embedding::Plugin {
+class COLOR_PANEL_PLUGIN_EXPORT ColorPanelPlugin
+    : public flutter_desktop_embedding::Plugin {
  public:
   static void RegisterWithRegistrar(
       flutter_desktop_embedding::PluginRegistrar *registrar);

plugins/file_chooser/BUILD.gn

@@ -30,7 +30,10 @@ published_shared_library("file_chooser") {
     ]
   }
 
-  defines = ["USE_FLATTENED_INCLUDES"]
+  defines = [
+    "FILE_CHOOSER_PLUGIN_IMPL",
+    "USE_FLATTENED_INCLUDES",
+  ]
 
   deps = [
     "//library:flutter_embedder",

plugins/file_chooser/linux/Makefile

@@ -24,9 +24,10 @@ EMBEDDER_LIB_FILE=$(EMBEDDER_LIBRARY_OUT_DIR)/lib$(EMBEDDER_LIB_NAME).so
 COMMON_DIR=$(CURDIR)/../common
 
 CXX=g++ -std=c++14
-CXXFLAGS= -Wall -Werror -shared -fPIC \
+CXXFLAGS= -Wall -Werror -shared -fPIC -fvisibility=hidden \
 	-I$(PROJECT_ROOT) \
 	-I$(EMBEDDER_LIBRARY_HEADER_DIR) \
+	-DFILE_CHOOSER_PLUGIN_IMPL \
 	$(shell pkg-config --cflags gtk+-3.0 jsoncpp)
 LDFLAGS= -L$(EMBEDDER_LIBRARY_OUT_DIR) \
 	$(shell pkg-config --libs gtk+-3.0 jsoncpp) \

plugins/file_chooser/linux/include/file_chooser/file_chooser_plugin.h

@@ -21,10 +21,17 @@
 #include <flutter_desktop_embedding/method_channel.h>
 #include <flutter_desktop_embedding/plugin_registrar.h>
 
+#ifdef FILE_CHOOSER_PLUGIN_IMPL
+#define FILE_CHOOSER_PLUGIN_EXPORT __attribute__((visibility("default")))
+#else
+#define FILE_CHOOSER_PLUGIN_EXPORT
+#endif
+
 namespace plugins_file_chooser {
 
 // Implements a file chooser plugin.
-class FileChooserPlugin : public flutter_desktop_embedding::Plugin {
+class FILE_CHOOSER_PLUGIN_EXPORT FileChooserPlugin
+    : public flutter_desktop_embedding::Plugin {
  public:
   static void RegisterWithRegistrar(
       flutter_desktop_embedding::PluginRegistrar *registrar);