Prevent excessive calls to deleteBackward method which may cause crashes on Android

core/2d/TextFieldTTF.cpp

@@ -24,6 +24,8 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ****************************************************************************/
 
+#include <algorithm>
+
 #include "2d/TextFieldTTF.h"
 
 #include "base/Director.h"
@@ -310,7 +312,7 @@ void TextFieldTTF::insertText(const char* text, size_t len)
     detachWithIME();
 }
 
-void TextFieldTTF::deleteBackward()
+void TextFieldTTF::deleteBackward(size_t numChars)
 {
     size_t len = _inputText.length();
     if (!len)
@@ -319,23 +321,33 @@ void TextFieldTTF::deleteBackward()
         return;
     }
 
-    // get the delete byte number
-    size_t deleteLen = 1;  // default, erase 1 byte
+    // Length of characters to delete is based on input editor, but the actual
+    // length of the displayed text may be less
+    numChars = std::min(numChars, len);
 
-    while (0x80 == (0xC0 & _inputText.at(len - deleteLen)))
+    size_t totalDeleteLen = 0;
+    for (auto i = 0; i < numChars; ++i)
     {
-        ++deleteLen;
+        // get the delete byte number
+        size_t deleteLen = 1;  // default, erase 1 byte
+
+        // Calculate the actual number of bytes to delete for a specific character
+        while (0x80 == (0xC0 & _inputText.at(len - totalDeleteLen - deleteLen)))
+        {
+            ++deleteLen;
+        }
+        totalDeleteLen += deleteLen;
     }
 
     if (_delegate &&
-        _delegate->onTextFieldDeleteBackward(this, _inputText.c_str() + len - deleteLen, static_cast<int>(deleteLen)))
+        _delegate->onTextFieldDeleteBackward(this, _inputText.c_str() + len - totalDeleteLen, static_cast<int>(totalDeleteLen)))
     {
         // delegate doesn't want to delete backwards
         return;
     }
 
     // if all text deleted, show placeholder string
-    if (len <= deleteLen)
+    if (len <= totalDeleteLen)
     {
         _inputText = "";
         _charCount = 0;
@@ -362,7 +374,7 @@ void TextFieldTTF::deleteBackward()
     }
     else
     {
-        std::string text(_inputText.c_str(), len - deleteLen);
+        std::string text(_inputText.c_str(), len - totalDeleteLen);
         setString(text);
     }
 }

core/2d/TextFieldTTF.h

@@ -261,7 +261,7 @@ class AX_DLL TextFieldTTF : public Label, public IMEDelegate
     virtual void didAttachWithIME() override;
     virtual void didDetachWithIME() override;
     virtual void insertText(const char* text, size_t len) override;
-    virtual void deleteBackward() override;
+    virtual void deleteBackward(size_t numChars) override;
     virtual std::string_view getContentText() override;
     virtual void controlKey(EventKeyboard::KeyCode keyCode) override;
 

core/base/IMEDelegate.h

@@ -124,7 +124,7 @@ class AX_DLL IMEDelegate
     * @js NA
     * @lua NA
     */
-    virtual void deleteBackward() {}
+    virtual void deleteBackward(size_t numChars) {}
 
     /**
     @brief    Called by IMEDispatcher after the user press control key.

core/base/IMEDispatcher.cpp

@@ -222,7 +222,7 @@ void IMEDispatcher::dispatchInsertText(const char* text, size_t len)
     } while (0);
 }
 
-void IMEDispatcher::dispatchDeleteBackward()
+void IMEDispatcher::dispatchDeleteBackward(int numChars)
 {
     do
     {
@@ -231,7 +231,7 @@ void IMEDispatcher::dispatchDeleteBackward()
         // there is no delegate attached to IME
         AX_BREAK_IF(!_impl->_delegateWithIme);
 
-        _impl->_delegateWithIme->deleteBackward();
+        _impl->_delegateWithIme->deleteBackward(numChars);
     } while (0);
 }
 

core/base/IMEDispatcher.h

@@ -65,7 +65,7 @@ class AX_DLL IMEDispatcher
      * @brief Dispatches the delete-backward operation.
      * @lua NA
      */
-    void dispatchDeleteBackward();
+    void dispatchDeleteBackward(int numChars);
 
     /**
      * @brief Dispatches the press control key operation.

core/platform/GLViewImpl.cpp

@@ -1220,7 +1220,7 @@ void GLViewImpl::onGLFWKeyCallback(GLFWwindow* /*window*/, int key, int /*scanco
         switch (g_keyCodeMap[key])
         {
         case EventKeyboard::KeyCode::KEY_BACKSPACE:
-            IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward();
+            IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward(1);
             break;
         case EventKeyboard::KeyCode::KEY_HOME:
         case EventKeyboard::KeyCode::KEY_KP_HOME:

core/platform/android/java/src/org/axmol/lib/AxmolGLSurfaceView.java

@@ -458,11 +458,11 @@ public void run() {
         });
     }
 
-    public void deleteBackward() {
+    public void deleteBackward(int numChars) {
         this.queueEvent(new Runnable() {
             @Override
             public void run() {
-                AxmolGLSurfaceView.this.mRenderer.handleDeleteBackward();
+                AxmolGLSurfaceView.this.mRenderer.handleDeleteBackward(numChars);
             }
         });
     }

core/platform/android/java/src/org/axmol/lib/AxmolRenderer.java

@@ -176,15 +176,15 @@ public void handleOnResume() {
     }
 
     private static native void nativeInsertText(final String text);
-    private static native void nativeDeleteBackward();
+    private static native void nativeDeleteBackward(final int numChars);
     private static native String nativeGetContentText();
 
     public void handleInsertText(final String text) {
         AxmolRenderer.nativeInsertText(text);
     }
 
-    public void handleDeleteBackward() {
-        AxmolRenderer.nativeDeleteBackward();
+    public void handleDeleteBackward(final int numChars) {
+        AxmolRenderer.nativeDeleteBackward(numChars);
     }
 
     public String getContentText() {

core/platform/android/java/src/org/axmol/lib/TextInputWrapper.java

@@ -90,8 +90,8 @@ public void afterTextChanged(final Editable s) {
             new_i += 1;
         }
 
-        for (; old_i < this.mText.length(); ++old_i) {
-            this.mGLSurfaceView.deleteBackward();
+        if (old_i < this.mText.length()) {
+            this.mGLSurfaceView.deleteBackward(this.mText.length() - old_i);
         }
 
         int nModified = s.length() - new_i;
@@ -118,13 +118,13 @@ public boolean onEditorAction(final TextView pTextView, final int pActionID, fin
         if (this.mGLSurfaceView.getEditText() == pTextView && this.isFullScreenEdit()) {
             // user press the action button, delete all old text and insert new text
             if (null != mOriginText) {
-                for (int i = this.mOriginText.length(); i > 0; i--) {
-                    this.mGLSurfaceView.deleteBackward();
+                if (!this.mOriginText.isEmpty()) {
+                    this.mGLSurfaceView.deleteBackward(this.mOriginText.length());
                 }
             }
-            
+
             String text = pTextView.getText().toString();
-            
+
             if (text != null) {
                 /* If user input nothing, translate "\n" to engine. */
                 if ( text.compareTo("") == 0) {
@@ -135,16 +135,16 @@ public boolean onEditorAction(final TextView pTextView, final int pActionID, fin
                     text += '\n';
                 }
             }
-            
+
             final String insertText = text;
             this.mGLSurfaceView.insertText(insertText);
 
         }
-        
+
         if (pActionID == EditorInfo.IME_ACTION_DONE) {
             this.mGLSurfaceView.requestFocus();
         }
         return false;
     }
 
-}
+}

core/platform/android/jni/Java_org_axmol_lib_AxmolRenderer.cpp

@@ -70,9 +70,9 @@ JNIEXPORT void JNICALL Java_org_axmol_lib_AxmolRenderer_nativeInsertText(JNIEnv*
     ax::IMEDispatcher::sharedDispatcher()->dispatchInsertText(pszText, strlen(pszText));
 }
 
-JNIEXPORT void JNICALL Java_org_axmol_lib_AxmolRenderer_nativeDeleteBackward(JNIEnv*, jclass)
+JNIEXPORT void JNICALL Java_org_axmol_lib_AxmolRenderer_nativeDeleteBackward(JNIEnv*, jclass, jint numChars)
 {
-    ax::IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward();
+    ax::IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward(numChars);
 }
 
 JNIEXPORT jstring JNICALL Java_org_axmol_lib_AxmolRenderer_nativeGetContentText(JNIEnv* env, jclass)

core/platform/ios/InputView-ios.mm

@@ -98,7 +98,7 @@ - (void)deleteBackward
         [self.myMarkedText release];
         self.myMarkedText = nil;
     }
-    ax::IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward();
+    ax::IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward(1);
 }
 
 - (void)insertText:(nonnull NSString*)text

core/platform/winrt/InputEvent.cpp

@@ -112,7 +112,7 @@ void KeyboardEvent::execute()
             //Director::getInstance()()->getKeypadDispatcher()->dispatchKeypadMSG(kTypeBackClicked);
             break;
         case AxmolKeyEvent::Back:
-            IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward();
+            IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward(1);
             break;
         case AxmolKeyEvent::Enter:
             IMEDispatcher::sharedDispatcher()->dispatchInsertText("\n", 1);

core/platform/winrt/Keyboard-winrt.cpp

@@ -304,7 +304,7 @@ void KeyBoardWinRT::OnWinRTKeyboardEvent(WinRTKeyboardEventType type, KeyEventAr
             switch (keyCode)
             {
             case EventKeyboard::KeyCode::KEY_BACKSPACE:
-                IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward();
+                IMEDispatcher::sharedDispatcher()->dispatchDeleteBackward(1);
                 break;
             case EventKeyboard::KeyCode::KEY_HOME:
             case EventKeyboard::KeyCode::KEY_KP_HOME:

core/ui/UITextFieldEx.cpp

@@ -617,7 +617,7 @@ void TextFieldEx::insertText(const char* text, size_t len)
     this->closeIME();
 }
 
-void TextFieldEx::deleteBackward()
+void TextFieldEx::deleteBackward(size_t numChars)
 {
     if (!_editable || !this->_enabled || 0 == _charCount)
     {
@@ -634,23 +634,33 @@ void TextFieldEx::deleteBackward()
         return;
     }
 
-    // get the delete byte number
-    size_t deleteLen = 1;  // default, erase 1 byte
+    // Length of characters to delete is based on input editor, but the actual
+    // length of the displayed text may be less
+    numChars = std::min(numChars, len);
 
-    while (0x80 == (0xC0 & _inputText.at(_insertPos - deleteLen)))
+    size_t totalDeleteLen = 0;
+    for (auto i = 0; i < numChars; ++i)
     {
-        ++deleteLen;
+        // get the delete byte number
+        size_t deleteLen = 1;  // default, erase 1 byte
+
+        // Calculate the actual number of bytes to delete for a specific character
+        while (0x80 == (0xC0 & _inputText.at(_insertPos - totalDeleteLen - deleteLen)))
+        {
+            ++deleteLen;
+        }
+        totalDeleteLen += deleteLen;
     }
 
     // if (_delegate && _delegate->onTextFieldDeleteBackward(this, _inputText.c_str() + len - deleteLen,
     // static_cast<int>(deleteLen)))
     //{
-    //     // delegate doesn't wan't to delete backwards
+    //     // delegate doesn't want to delete backwards
     //     return;
     // }
 
     // if all text deleted, show placeholder string
-    if (len <= deleteLen)
+    if (len <= totalDeleteLen)
     {
         __moveCursor(-1);
 
@@ -670,7 +680,7 @@ void TextFieldEx::deleteBackward()
 
     // set new input text
     std::string text = _inputText;  // (inputText.c_str(), len - deleteLen);
-    text.erase(_insertPos - deleteLen, deleteLen);
+    text.erase(_insertPos - totalDeleteLen, totalDeleteLen);
 
     __moveCursor(-1);
 

core/ui/UITextFieldEx.h

@@ -140,7 +140,7 @@ class AX_DLL TextFieldEx : public Widget, public IMEDelegate
     bool canAttachWithIME() override;
     bool canDetachWithIME() override;
 
-    void deleteBackward() override;
+    void deleteBackward(size_t numChars) override;
     std::string_view getContentText() override;
 
     void handleDeleteKeyEvent();

core/ui/axmol-ui.h

@@ -40,6 +40,7 @@ THE SOFTWARE.
 #include "ui/UIListView.h"
 #include "ui/UISlider.h"
 #include "ui/UITextField.h"
+#include "ui/UITextFieldEx.h"
 #include "ui/UITextBMFont.h"
 #include "ui/UIPageView.h"
 #include "ui/UIHelper.h"