clipboard: fix wrong memory layout with tiny string

.github/workflows/ci.yml

@@ -21,6 +21,7 @@ jobs:
       - name: Lint
         run: |
           find macosfrontend macosnotifications webpanel src tests -name '*.cpp' -o -name '*.h' | xargs clang-format -Werror --dry-run -style=file:fcitx5/.clang-format
+          clang-format -Werror --dry-run macosfrontend/pasteboard.mm
           swift-format lint --configuration .swift-format.json -rs macosfrontend macosnotifications src assets
           ./check-code-style.sh
           file assets/zh-Hans.lproj/Localizable.strings | grep UTF-16

macosfrontend/CMakeLists.txt

@@ -10,7 +10,7 @@ _swift_generate_cxx_header(
     SEARCH_PATHS "${CMAKE_CURRENT_SOURCE_DIR}"
 )
 
-add_library(macosfrontend STATIC macosfrontend.cpp keycode.cpp)
+add_library(macosfrontend STATIC macosfrontend.cpp pasteboard.mm keycode.cpp)
 add_dependencies(macosfrontend SwiftFrontend)
 target_link_libraries(macosfrontend Fcitx5::Core)
 target_include_directories(macosfrontend PUBLIC

macosfrontend/macosfrontend.cpp

@@ -38,9 +38,8 @@ void MacosFrontend::pollPasteboard() {
             if (auto clipboard =
                     instance_->addonManager().addon("clipboard", true)) {
                 bool isPassword = false;
-                const char *p = SwiftFrontend::getPasteboardString(&isPassword);
-                if (p) {
-                    std::string str = p;
+                std::string str = getPasteboardString(&isPassword);
+                if (!str.empty()) {
                     clipboard->call<IClipboard::setClipboardV2>("", str,
                                                                 isPassword);
                     FCITX_DEBUG() << "Add to clipboard: " << str;

macosfrontend/macosfrontend.h

@@ -145,6 +145,8 @@ class MacosFrontendFactory : public AddonFactory {
     }
 };
 
+std::string getPasteboardString(bool *isPassword);
+
 } // namespace fcitx
 
 #endif

macosfrontend/macosfrontend.swift

@@ -82,22 +82,3 @@ public func getCursorCoordinates(
   }
   return false
 }
-
-private var lastChangeCount = 0
-private var data: Data?
-private let passwordType = NSPasteboard.PasteboardType("org.nspasteboard.ConcealedType")
-
-// Retrieve the current string data from the default pasteboard.
-public func getPasteboardString(_ isPassword: UnsafeMutablePointer<Bool>) -> UnsafePointer<CChar>? {
-  let pasteboard = NSPasteboard.general
-  if pasteboard.changeCount == lastChangeCount {
-    return nil
-  }
-  lastChangeCount = pasteboard.changeCount
-  data = pasteboard.data(forType: .string)
-  if let data = data {
-    isPassword.pointee = pasteboard.string(forType: passwordType) != nil
-    return data.withUnsafeBytes { $0.baseAddress?.assumingMemoryBound(to: CChar.self) }
-  }
-  return nil
-}

macosfrontend/pasteboard.mm

@@ -0,0 +1,21 @@
+#include "macosfrontend.h"
+#import <AppKit/AppKit.h>
+
+static int lastChangeCount = 0;
+static NSPasteboardType passwordType = @"org.nspasteboard.ConcealedType";
+
+namespace fcitx {
+std::string getPasteboardString(bool *isPassword) {
+  NSPasteboard *pasteboard = [NSPasteboard generalPasteboard];
+  if (pasteboard.changeCount == lastChangeCount) {
+    return "";
+  }
+  lastChangeCount = (int)pasteboard.changeCount;
+  NSString *stringData = [pasteboard stringForType:NSPasteboardTypeString];
+  if (stringData) {
+    *isPassword = ([pasteboard stringForType:passwordType] != nil);
+    return std::string([stringData UTF8String]);
+  }
+  return "";
+}
+} // namespace fcitx