Add create command for plugin support

lib/commands/create.dart

@@ -115,16 +115,6 @@ class ELinuxCreateCommand extends CreateCommand {
     try {
       for (final Directory projectType
           in eLinuxTemplates.listSync().whereType<Directory>()) {
-        final Directory sourceRunnerCommon =
-            projectType.childDirectory('runner');
-        if (!sourceRunnerCommon.existsSync()) {
-          continue;
-        }
-        final Directory sourceFlutter = projectType.childDirectory('flutter');
-        if (!sourceFlutter.existsSync()) {
-          continue;
-        }
-
         final Directory dest = templates
             .childDirectory(projectType.basename)
             .childDirectory('elinux.tmpl');
@@ -133,8 +123,19 @@ class ELinuxCreateCommand extends CreateCommand {
         }
 
         copyDirectory(projectType, dest);
-        copyDirectory(sourceFlutter, dest.childDirectory('flutter'));
-        copyDirectory(sourceRunnerCommon, dest.childDirectory('runner'));
+        if (projectType.basename == 'app') {
+          final Directory sourceRunnerCommon =
+              projectType.childDirectory('runner');
+          if (!sourceRunnerCommon.existsSync()) {
+            continue;
+          }
+          final Directory sourceFlutter = projectType.childDirectory('flutter');
+          if (!sourceFlutter.existsSync()) {
+            continue;
+          }
+          copyDirectory(sourceFlutter, dest.childDirectory('flutter'));
+          copyDirectory(sourceRunnerCommon, dest.childDirectory('runner'));
+        }
         created.add(dest);
       }
       return await runInternal();

lib/elinux_build_target.dart

@@ -344,7 +344,7 @@ class NativeBundle {
       }
       writeGeneratedCmakeConfig(Cache.flutterRoot, eLinuxProject, environment);
 
-      //createPluginSymlinks(eLinuxProject.parent);
+      createPluginSymlinks(eLinuxProject.parent);
     }
 
     // Run the native build.

lib/elinux_plugins.dart

@@ -6,6 +6,8 @@
 
 // @dart = 2.8
 
+import 'dart:convert';
+
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
@@ -13,6 +15,7 @@ import 'package:flutter_tools/src/build_system/targets/web.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/dart/language_version.dart';
 import 'package:flutter_tools/src/dart/package_map.dart';
+import 'package:flutter_tools/src/features.dart';
 import 'package:flutter_tools/src/flutter_plugins.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/platform_plugins.dart';
@@ -460,3 +463,77 @@ void _renderTemplateToFile(String template, dynamic context, String filePath) {
   file.createSync(recursive: true);
   file.writeAsStringSync(renderedTemplate);
 }
+
+// Key strings for the .flutter-plugins-dependencies file.
+const String _kFlutterPluginsPluginListKey = 'plugins';
+const String _kFlutterPluginsNameKey = 'name';
+const String _kFlutterPluginsPathKey = 'path';
+
+/// For each platform that uses them, creates symlinks within the platform
+/// directory to each plugin used on that platform.
+///
+/// If |force| is true, the symlinks will be recreated, otherwise they will
+/// be created only if missing.
+///
+/// This uses [project.flutterPluginsDependenciesFile], so it should only be
+/// run after refreshPluginList has been run since the last plugin change.
+void createPluginSymlinks(FlutterProject project,
+    {bool force = false,
+    @visibleForTesting FeatureFlags featureFlagsOverride}) {
+  Map<String, Object> platformPlugins;
+  final String pluginFileContent =
+      _readFileContent(project.flutterPluginsDependenciesFile);
+
+  if (pluginFileContent != null) {
+    final Map<String, Object> pluginInfo =
+        json.decode(pluginFileContent) as Map<String, Object>;
+    platformPlugins =
+        pluginInfo[_kFlutterPluginsPluginListKey] as Map<String, Object>;
+  }
+  platformPlugins ??= <String, Object>{};
+
+  final ELinuxProject eLinuxProject = ELinuxProject.fromFlutter(project);
+  if (eLinuxProject.existsSync()) {
+    _createPlatformPluginSymlinks(
+      eLinuxProject.pluginSymlinkDirectory,
+      platformPlugins[eLinuxProject.pluginConfigKey] as List<Object>,
+      force: force,
+    );
+  }
+}
+
+/// Returns the contents of [File] or [null] if that file does not exist.
+String _readFileContent(File file) {
+  return file.existsSync() ? file.readAsStringSync() : null;
+}
+
+/// Creates [symlinkDirectory] containing symlinks to each plugin listed in [platformPlugins].
+///
+/// If [force] is true, the directory will be created only if missing.
+void _createPlatformPluginSymlinks(
+    Directory symlinkDirectory, List<Object> platformPlugins,
+    {bool force = false}) {
+  if (force && symlinkDirectory.existsSync()) {
+    // Start fresh to avoid stale links.
+    symlinkDirectory.deleteSync(recursive: true);
+  }
+  symlinkDirectory.createSync(recursive: true);
+  if (platformPlugins == null) {
+    return;
+  }
+  for (final Map<String, Object> pluginInfo
+      in platformPlugins.cast<Map<String, Object>>()) {
+    final String name = pluginInfo[_kFlutterPluginsNameKey] as String;
+    final String path = pluginInfo[_kFlutterPluginsPathKey] as String;
+    final Link link = symlinkDirectory.childLink(name);
+    if (link.existsSync()) {
+      continue;
+    }
+    try {
+      link.createSync(path);
+    } on FileSystemException catch (e) {
+      handleSymlinkException(e, platform: globals.platform, os: globals.os);
+      rethrow;
+    }
+  }
+}

templates/plugin/.gitignore

@@ -0,0 +1 @@
+flutter/

templates/plugin/CMakeLists.txt.tmpl

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.15)
+set(PROJECT_NAME "{{projectName}}")
+project(${PROJECT_NAME} LANGUAGES CXX)
+
+# This value is used when generating builds using this plugin, so it must
+# not be changed
+set(PLUGIN_NAME "{{projectName}}_plugin")
+
+add_library(${PLUGIN_NAME} SHARED
+  "{{pluginClassSnakeCase}}.cc"
+)
+apply_standard_settings(${PLUGIN_NAME})
+set_target_properties(${PLUGIN_NAME} PROPERTIES
+  CXX_VISIBILITY_PRESET hidden)
+target_compile_definitions(${PLUGIN_NAME} PRIVATE FLUTTER_PLUGIN_IMPL)
+target_include_directories(${PLUGIN_NAME} INTERFACE
+  "${CMAKE_CURRENT_SOURCE_DIR}/include")
+target_link_libraries(${PLUGIN_NAME} PRIVATE flutter flutter_wrapper_plugin)
+
+# List of absolute paths to libraries that should be bundled with the plugin
+set({{projectName}}_bundled_libraries
+  ""
+  PARENT_SCOPE
+)

templates/plugin/include/projectName.tmpl/pluginClassSnakeCase.h.tmpl

@@ -0,0 +1,23 @@
+#ifndef FLUTTER_PLUGIN_{{pluginClassCapitalSnakeCase}}_H_
+#define FLUTTER_PLUGIN_{{pluginClassCapitalSnakeCase}}_H_
+
+#include <flutter_plugin_registrar.h>
+
+#ifdef FLUTTER_PLUGIN_IMPL
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllexport)
+#else
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllimport)
+#endif
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+FLUTTER_PLUGIN_EXPORT void {{pluginClass}}RegisterWithRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar);
+
+#if defined(__cplusplus)
+}  // extern "C"
+#endif
+
+#endif  // FLUTTER_PLUGIN_{{pluginClassCapitalSnakeCase}}_H_

templates/plugin/pluginClassSnakeCase.cc.tmpl

@@ -0,0 +1,69 @@
+#include "include/{{projectName}}/{{pluginClassSnakeCase}}.h"
+
+#include <flutter/method_channel.h>
+#include <flutter/plugin_registrar.h>
+#include <flutter/standard_method_codec.h>
+
+#include <map>
+#include <memory>
+#include <sstream>
+
+namespace {
+
+class {{pluginClass}} : public flutter::Plugin {
+ public:
+  static void RegisterWithRegistrar(flutter::PluginRegistrar *registrar);
+
+  {{pluginClass}}();
+
+  virtual ~{{pluginClass}}();
+
+ private:
+  // Called when a method is called on this plugin's channel from Dart.
+  void HandleMethodCall(
+      const flutter::MethodCall<flutter::EncodableValue> &method_call,
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+};
+
+// static
+void {{pluginClass}}::RegisterWithRegistrar(
+    flutter::PluginRegistrar *registrar) {
+  auto channel =
+      std::make_unique<flutter::MethodChannel<flutter::EncodableValue>>(
+          registrar->messenger(), "{{projectName}}",
+          &flutter::StandardMethodCodec::GetInstance());
+
+  auto plugin = std::make_unique<{{pluginClass}}>();
+
+  channel->SetMethodCallHandler(
+      [plugin_pointer = plugin.get()](const auto &call, auto result) {
+        plugin_pointer->HandleMethodCall(call, std::move(result));
+      });
+
+  registrar->AddPlugin(std::move(plugin));
+}
+
+{{pluginClass}}::{{pluginClass}}() {}
+
+{{pluginClass}}::~{{pluginClass}}() {}
+
+void {{pluginClass}}::HandleMethodCall(
+    const flutter::MethodCall<flutter::EncodableValue> &method_call,
+    std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {
+  if (method_call.method_name().compare("getPlatformVersion") == 0) {
+    std::ostringstream version_stream;
+    version_stream << "eLinux";
+    result->Success(flutter::EncodableValue(version_stream.str()));
+  } else {
+    result->NotImplemented();
+  }
+}
+
+}  // namespace
+
+void {{pluginClass}}RegisterWithRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar) {
+  {{pluginClass}}::RegisterWithRegistrar(
+      flutter::PluginRegistrarManager::GetInstance()
+          ->GetRegistrar<flutter::PluginRegistrar>(registrar));
+}

templates/template_manifest.json

@@ -11,6 +11,10 @@
         "templates/app/elinux.tmpl/runner/flutter_window.cc",
         "templates/app/elinux.tmpl/runner/flutter_window.h",
         "templates/app/elinux.tmpl/runner/main.cc",
+        "templates/plugin/elinux.tmpl/.gitignore",
+        "templates/plugin/elinux.tmpl/CMakeLists.txt.tmpl",
+        "templates/plugin/elinux.tmpl/include/projectName.tmpl/pluginClassSnakeCase.h.tmpl",
+        "templates/plugin/elinux.tmpl/pluginClassSnakeCase.cc.tmpl",
 
         "templates/app/.gitignore.tmpl",
         "templates/app/.idea/libraries/Dart_SDK.xml.tmpl",