[linux] Implements basic ASCII text input

linux/library/Makefile

@@ -25,7 +25,7 @@ LDFLAGS= -L$(CURDIR) \
 
 LIBRARIES=lib$(FLUTTER_ENGINE_LIB).so
 HEADERS=$(shell find include/ -type f -name '*.h')
-SOURCES=$(wildcard src/*.cc)
+SOURCES=$(shell find src/ -type f -name '*.cc')
 
 .PHONY: all
 all: $(LIBRARY_OUT)

linux/library/include/flutter_desktop_embedding/common/platform_protocol.h

@@ -0,0 +1,26 @@
+// Copyright 2018 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 LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_COMMON_PLATFORM_PROTOCOL_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_COMMON_PLATFORM_PROTOCOL_H_
+
+// Defines a set of common JSON keys for communicating with the Flutter Engine's
+// platform message protocol.
+namespace flutter_desktop_embedding {
+
+extern const char kMethodKey[];
+extern const char kArgumentsKey[];
+
+}  // namespace flutter_desktop_embedding
+
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_COMMON_PLATFORM_PROTOCOL_H_

linux/library/include/flutter_desktop_embedding/file_chooser_plugin.h

@@ -11,8 +11,8 @@
 // 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 LINUX_INCLUDE_FILE_CHOOSER_PLUGIN_H_
-#define LINUX_INCLUDE_FILE_CHOOSER_PLUGIN_H_
+#ifndef LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FILE_CHOOSER_PLUGIN_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FILE_CHOOSER_PLUGIN_H_
 #include "plugin.h"
 
 namespace flutter_desktop_embedding {
@@ -28,4 +28,4 @@ class FileChooserPlugin : public Plugin {
 
 }  // namespace flutter_desktop_embedding
 
-#endif  // LINUX_INCLUDE_FILE_CHOOSER_PLUGIN_H_
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FILE_CHOOSER_PLUGIN_H_

linux/library/include/flutter_desktop_embedding/flutter_embedder.h

@@ -11,8 +11,8 @@
 // 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 LINUX_LIBRARY_INCLUDE_FLUTTER_EMBEDDER_H_
-#define LINUX_LIBRARY_INCLUDE_FLUTTER_EMBEDDER_H_
+#ifndef LINUX_LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FLUTTER_EMBEDDER_H_
+#define LINUX_LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FLUTTER_EMBEDDER_H_
 
 // Epoxy must be included before any graphics-related code.
 #include <epoxy/gl.h>
@@ -79,4 +79,4 @@ void FlutterWindowLoop(GLFWwindow *flutter_window);
 
 }  // namespace flutter_desktop_embedding
 
-#endif  // LINUX_LIBRARY_INCLUDE_FLUTTER_EMBEDDER_H_
+#endif  // LINUX_LIBRARY_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_FLUTTER_EMBEDDER_H_

linux/library/include/flutter_desktop_embedding/input/keyboard_hook_handler.h

@@ -0,0 +1,34 @@
+// Copyright 2018 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 LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_INPUT_KEYBOARD_HOOK_HANDLER_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_INPUT_KEYBOARD_HOOK_HANDLER_H_
+
+#include <GLFW/glfw3.h>
+
+namespace flutter_desktop_embedding {
+
+// Abstract class for handling keyboard input events.
+class KeyboardHookHandler {
+ public:
+  // A function for hooking into keyboard input.
+  virtual void KeyboardHook(GLFWwindow *window, int key, int scancode,
+                            int action, int mods) = 0;
+
+  // A function for hooking into unicode code point input.
+  virtual void CharHook(GLFWwindow *window, unsigned int code_point) = 0;
+};
+
+}  // namespace flutter_desktop_embedding
+
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_INPUT_KEYBOARD_HOOK_HANDLER_H_

linux/library/include/flutter_desktop_embedding/plugin.h

@@ -11,12 +11,15 @@
 // 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 LINUX_INCLUDE_PLUGIN_H_
-#define LINUX_INCLUDE_PLUGIN_H_
+#ifndef LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_H_
 #include <json/json.h>
 
+#include <functional>
 #include <string>
 
+#include <embedder.h>
+
 namespace flutter_desktop_embedding {
 
 // Represents a plugin that can be registered with the Flutter Embedder.
@@ -31,14 +34,13 @@ class Plugin {
   // |input_blocking| Determines whether user input should be blocked during the
   // duration of this plugin's platform callback handler (in most cases this
   // can be set to false).
-  explicit Plugin(std::string channel, bool input_blocking = false)
-      : channel_(channel), input_blocking_(input_blocking) {}
-  virtual ~Plugin() {}
+  explicit Plugin(std::string channel, bool input_blocking = false);
+  virtual ~Plugin();
 
   // Handles a platform message sent on this platform's channel.
   //
-  // If some error has occurred or there is no valid response that can be made,
-  // must return a Json::nullValue object.
+  // If some error has occurred or there is no valid response that can be
+  // made, must return a Json::nullValue object.
   virtual Json::Value HandlePlatformMessage(const Json::Value &message) = 0;
 
   // Returns the channel on which this plugin listens.
@@ -50,11 +52,22 @@ class Plugin {
   // while waiting for this plugin to handle its platform message.
   virtual bool input_blocking() const { return input_blocking_; }
 
+  // Sets the pointer to the caller-owned Flutter Engine.
+  //
+  // The embedder typically sets this pointer rather than the client.
+  virtual void set_flutter_engine(FlutterEngine engine) { engine_ = engine; }
+
+ protected:
+  // Sends a message to the flutter engine on this Plugin's channel.
+  void SendMessageToFlutterEngine(const Json::Value &json);
+
  private:
   std::string channel_;
+  // Caller-owned instance of the Flutter Engine.
+  FlutterEngine engine_;
   bool input_blocking_;
 };
 
 }  // namespace flutter_desktop_embedding
 
-#endif  // LINUX_INCLUDE_FLUTTER_EMBEDDER_PLUGIN_H_
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_H_

linux/library/include/flutter_desktop_embedding/plugin_handler.h

@@ -11,11 +11,10 @@
 // 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 LINUX_INCLUDE_PLUGIN_HANDLER_H_
-#define LINUX_INCLUDE_PLUGIN_HANDLER_H_
-#include <json/json.h>
+#ifndef LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_HANDLER_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_HANDLER_H_
 
-#include <functional>
+#include <json/json.h>
 #include <map>
 #include <memory>
 #include <string>
@@ -58,4 +57,4 @@ class PluginHandler {
 
 }  // namespace flutter_desktop_embedding
 
-#endif  // LINUX_INCLUDE_PLUGIN_HANDLER_H_
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_PLUGIN_HANDLER_H_

linux/library/include/flutter_desktop_embedding/text_input_model.h

@@ -0,0 +1,97 @@
+// Copyright 2018 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 LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_MODEL_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_MODEL_H_
+
+#include <json/json.h>
+#include <string>
+
+namespace flutter_desktop_embedding {
+// Handles underlying text input state, using a simple ASCII model.
+//
+// Ignores special states like "insert mode" for now.
+class TextInputModel {
+ public:
+  explicit TextInputModel(int client_id);
+  virtual ~TextInputModel();
+
+  // Attempts to set the text state.
+  //
+  // Returns false if the state is not valid (base or extent are out of
+  // bounds, or base is less than extent).
+  bool SetEditingState(size_t selection_base, size_t selection_extent,
+                       const std::string &text);
+
+  // Adds a character.
+  //
+  // Either appends after the cursor (when selection base and extent are the
+  // same), or deletes the selected characters, replacing the text with the
+  // character specified.
+  void AddCharacter(char c);
+
+  // Deletes either the selection, or one character ahead of the cursor.
+  //
+  // Deleting one character ahead of the cursor occurs when the selection base
+  // and extent are the same.
+  //
+  // Returns true if any deletion actually occurred.
+  bool Delete();
+
+  // Deletes either the selection, or one character behind the cursor.
+  //
+  // Deleting one character behind the cursor occurs when the selection base
+  // and extent are the same.
+  //
+  // Returns true if any deletion actually occurred.
+  bool Backspace();
+
+  // Attempts to move the cursor backward.
+  //
+  // Returns true if the cursor could be moved. Changes base and extent to be
+  // equal to either the extent (if extent is at the end of the string), or
+  // for extent to be equal to
+  bool MoveCursorBack();
+
+  // Attempts to move the cursor forward.
+  //
+  // Returns true if the cursor could be moved.
+  bool MoveCursorForward();
+
+  // Attempts to move the cursor to the beginning.
+  //
+  // Returns true if the cursor could be moved.
+  void MoveCursorToBeginning();
+
+  // Attempts to move the cursor to the back.
+  //
+  // Returns true if the cursor could be moved.
+  void MoveCursorToEnd();
+
+  // Returns the state in the form of a platform message.
+  Json::Value GetState();
+
+  int client_id() const { return client_id_; }
+
+ private:
+  void DeleteSelected();
+
+  std::string text_;
+  int client_id_;
+  std::string::iterator selection_base_;
+  std::string::iterator selection_extent_;
+};
+
+}  // namespace flutter_desktop_embedding
+
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_MODEL_H_

linux/library/include/flutter_desktop_embedding/text_input_plugin.h

@@ -0,0 +1,55 @@
+// Copyright 2018 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 LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_PLUGIN_H_
+#define LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_PLUGIN_H_
+
+#include <map>
+#include <memory>
+
+#include <flutter_desktop_embedding/input/keyboard_hook_handler.h>
+
+#include "plugin.h"
+#include "text_input_model.h"
+
+namespace flutter_desktop_embedding {
+
+// Implements a text input plugin.
+//
+// Specifically handles window events within GLFW.
+class TextInputPlugin : public KeyboardHookHandler, public Plugin {
+ public:
+  TextInputPlugin();
+  virtual ~TextInputPlugin();
+
+  // Plugin.
+  Json::Value HandlePlatformMessage(const Json::Value &message) override;
+
+  // KeyboardHookHandler.
+  void KeyboardHook(GLFWwindow *window, int key, int scancode, int action,
+                    int mods) override;
+
+  // KeyboardHookHandler.
+  void CharHook(GLFWwindow *window, unsigned int code_point) override;
+
+ private:
+  // Mapping of client IDs to text input models.
+  std::map<int, std::unique_ptr<TextInputModel>> input_models_;
+
+  // The active model. nullptr if not set.
+  TextInputModel *active_model_;
+};
+
+}  // namespace flutter_desktop_embedding
+
+#endif  // LINUX_INCLUDE_FLUTTER_DESKTOP_EMBEDDING_TEXT_INPUT_PLUGIN_H_

linux/library/src/common/platform_protocol.cc

@@ -0,0 +1,21 @@
+// Copyright 2018 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.
+#include <flutter_desktop_embedding/common/platform_protocol.h>
+
+namespace flutter_desktop_embedding {
+
+constexpr char kMethodKey[] = "method";
+constexpr char kArgumentsKey[] = "args";
+
+}  // namespace flutter_desktop_embedding

linux/library/src/file_chooser_plugin.cc

@@ -194,7 +194,8 @@ Json::Value FileChooserPlugin::HandlePlatformMessage(
     g_slist_free(files);
   }
   g_object_unref(chooser);
-  return CreateCallback(filenames, chooser_res, args);
+  SendMessageToFlutterEngine(CreateCallback(filenames, chooser_res, args));
+  return Json::nullValue;
 }
 
 }  // namespace flutter_desktop_embedding