ANDROID: Use SAF if a directory is not writeable

backends/fs/posix/posix-fs.cpp

@@ -68,7 +68,14 @@ bool POSIXFilesystemNode::isReadable() const {
 }
 
 bool POSIXFilesystemNode::isWritable() const {
-	return access(_path.c_str(), W_OK) == 0;
+	bool retVal = access(_path.c_str(), W_OK) == 0;
+#if defined(ANDROID_PLAIN_PORT)
+	if (!retVal) {
+		// Update return value if going through Android's SAF grants the permission
+		retVal = JNI::isDirectoryWritableWithSAF(_path);
+	}
+#endif // ANDROID_PLAIN_PORT
+	return retVal;
 }
 
 void POSIXFilesystemNode::setFlags() {

backends/platform/android/jni-android.cpp

@@ -91,6 +91,7 @@ jmethodID JNI::_MID_deinitSurface = 0;
 jmethodID JNI::_MID_createDirectoryWithSAF = 0;
 jmethodID JNI::_MID_createFileWithSAF = 0;
 jmethodID JNI::_MID_closeFileWithSAF = 0;
+jmethodID JNI::_MID_isDirectoryWritableWithSAF = 0;
 
 jmethodID JNI::_MID_EGL10_eglSwapBuffers = 0;
 
@@ -561,6 +562,7 @@ void JNI::create(JNIEnv *env, jobject self, jobject asset_manager,
 	FIND_METHOD(, createDirectoryWithSAF, "(Ljava/lang/String;)Z");
 	FIND_METHOD(, createFileWithSAF, "(Ljava/lang/String;)Ljava/lang/String;");
 	FIND_METHOD(, closeFileWithSAF, "(Ljava/lang/String;)V");
+	FIND_METHOD(, isDirectoryWritableWithSAF, "(Ljava/lang/String;)Z");
 
 	_jobj_egl = env->NewGlobalRef(egl);
 	_jobj_egl_display = env->NewGlobalRef(egl_display);
@@ -814,7 +816,6 @@ Common::U32String JNI::createFileWithSAF(const Common::String &filePath) {
 
 	Common::U32String hackyFilenameStr = convertFromJString(env, hackyFilenameJSTR);
 
-	//LOGD("JNI - _MID_createFileWithSAF returned %s", hackyFilenameStr.c_str());
 	env->DeleteLocalRef(hackyFilenameJSTR);
 
 	return hackyFilenameStr;
@@ -836,4 +837,22 @@ void JNI::closeFileWithSAF(const Common::String &hackyFilename) {
 
 }
 
+bool JNI::isDirectoryWritableWithSAF(const Common::String &dirPath) {
+	JNIEnv *env = JNI::getEnv();
+	jstring javaDirPath = env->NewStringUTF(dirPath.c_str());
+
+	bool isWritable = env->CallBooleanMethod(_jobj, _MID_isDirectoryWritableWithSAF, javaDirPath);
+
+	if (env->ExceptionCheck()) {
+		LOGE("JNI - Failed to check if directory is writable SAF enhanced method");
+
+		env->ExceptionDescribe();
+		env->ExceptionClear();
+		isWritable = false;
+	}
+
+	return isWritable;
+
+}
+
 #endif

backends/platform/android/jni-android.h

@@ -87,6 +87,7 @@ public:
 	static bool createDirectoryWithSAF(const Common::String &dirPath);
 	static Common::U32String createFileWithSAF(const Common::String &filePath);
 	static void closeFileWithSAF(const Common::String &hackyFilename);
+	static bool isDirectoryWritableWithSAF(const Common::String &dirPath);
 
 private:
 	static JavaVM *_vm;
@@ -119,6 +120,7 @@ private:
 	static jmethodID _MID_createDirectoryWithSAF;
 	static jmethodID _MID_createFileWithSAF;
 	static jmethodID _MID_closeFileWithSAF;
+	static jmethodID _MID_isDirectoryWritableWithSAF;
 
 	static jmethodID _MID_EGL10_eglSwapBuffers;
 

backends/platform/android/org/scummvm/scummvm/ScummVM.java

@@ -74,6 +74,7 @@ public abstract class ScummVM implements SurfaceHolder.Callback, Runnable {
 	abstract protected boolean createDirectoryWithSAF(String dirPath);
 	abstract protected String createFileWithSAF(String filePath);
 	abstract protected void closeFileWithSAF(String hackyFilename);
+	abstract protected boolean isDirectoryWritableWithSAF(String dirPath);
 
 	public ScummVM(AssetManager asset_manager, SurfaceHolder holder, final MyScummVMDestroyedCallback scummVMDestroyedCallback) {
 		_asset_manager = asset_manager;

backends/platform/android/org/scummvm/scummvm/ScummVMActivity.java

@@ -417,19 +417,19 @@ public class ScummVMActivity extends Activity implements OnKeyboardVisibilityLis
 
 								// TODO - "Swipe" behavior does not seem to work currently. Should we support it?
 								public void swipeLeft() {
-									//Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeLeft");
+//									Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeLeft");
 								}
 
 								public void swipeRight() {
-									//Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeRight" );
+//									Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeRight" );
 								}
 
 								public void swipeDown() {
-									//Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeDown" );
+//									Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeDown" );
 								}
 
 								public void swipeUp() {
-									//Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeUp ");
+//									Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - swipeUp ");
 								}
 								public void onKey(int key, int[] keysAround) {
 //									Log.d(ScummVM.LOG_TAG, "SHOW KEYBOARD - 001 - onKey key: " + key );
@@ -583,7 +583,6 @@ public class ScummVMActivity extends Activity implements OnKeyboardVisibilityLis
 		}
 	};
 
-
 	private class MyScummVM extends ScummVM {
 
 		public MyScummVM(SurfaceHolder holder, final MyScummVMDestroyedCallback destroyedCallback) {
@@ -793,6 +792,36 @@ public class ScummVMActivity extends Activity implements OnKeyboardVisibilityLis
 			return retRes[0];
 		}
 
+
+		// This is a simplified version of createDirectoryWithSAF
+		// TODO Maybe we could merge isDirectoryWritableWithSAF() with createDirectoryWithSAF() using an extra argument parameter
+		@Override
+		protected boolean isDirectoryWritableWithSAF(String dirPath) {
+			final boolean[] retRes = {false};
+
+			Log.d(ScummVM.LOG_TAG, "Check if folder writable: " + dirPath);
+			File folderToCheck = new File (dirPath);
+			if (folderToCheck.canWrite()) {
+				Log.d(ScummVM.LOG_TAG, "This path has write permission!" + dirPath);
+			} else {
+				Log.d(ScummVM.LOG_TAG, "Trying to get write access with SAF");
+				if (getStorageAccessFrameworkTreeUri() == null) {
+					requestStorageAccessFramework(dirPath);
+				} else {
+					Log.d(ScummVM.LOG_TAG, "Already requested Storage Access (Storage Access Framework) in the past (share prefs saved)!");
+				}
+			}
+
+			if (canWriteFile(folderToCheck, true)) {
+				Log.d(ScummVM.LOG_TAG, "(post SAF request) Writing is possible for this directory node");
+				retRes[0] = true;
+			} else {
+				Log.d(ScummVM.LOG_TAG, "(post SAF request) Error - writing is still not possible for this directory node");
+			}
+
+			return retRes[0];
+		}
+
 		@Override
 		protected String createFileWithSAF(String filePath) {
 			final String[] retResStr = {""};
@@ -2158,6 +2187,7 @@ public class ScummVMActivity extends Activity implements OnKeyboardVisibilityLis
 		_scummvm.displayMessageOnOSD(getString(R.string.saf_request_prompt) + dirPathSample);
 
 		if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
+			// Directory picker
 			Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
 			intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION
 			                | Intent.FLAG_GRANT_WRITE_URI_PERMISSION
@@ -2298,14 +2328,20 @@ public class ScummVMActivity extends Activity implements OnKeyboardVisibilityLis
 		} catch (Exception ignored) {
 			originalDirectory = true;
 		}
+
 		Uri treeUri;
 		if ((treeUri = getStorageAccessFrameworkTreeUri()) == null) {
 			return null;
 		}
+
 		DocumentFile dof = DocumentFile.fromTreeUri(getApplicationContext(), treeUri);
 		if (originalDirectory) {
 			return dof;
 		}
+
+		// Important note: We cannot assume that anything sent here is a relative path on top of the *ONLY* SAF "root" path
+		//                 since the the user could select another SD Card (from multiple inserted or replaces the current one and inserts another)
+		// TODO Can we translate our path string "/storage/XXXX-XXXXX/folder/doc.ext' a content URI? or a document URI?
 		String[] parts = relPath.split("\\/");
 		for (int i = 0; i < parts.length; i++) {
 			DocumentFile nextDof = dof.findFile(parts[i]);