Android: Allow SDL_IOFromFile to open content:// URI. (#9696)

android-project/app/proguard-rules.pro

@@ -48,6 +48,7 @@
     int openURL(java.lang.String);
     int showToast(java.lang.String, int, int, int, int);
     native java.lang.String nativeGetHint(java.lang.String);
+    int openFileDescriptor(java.lang.String, java.lang.String);
 }
 
 -keep,includedescriptorclasses,allowoptimization class org.libsdl.app.HIDDeviceManager {

android-project/app/src/main/java/org/libsdl/app/SDLActivity.java

@@ -23,6 +23,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
+import android.os.ParcelFileDescriptor;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.util.SparseArray;
@@ -44,6 +45,7 @@ import android.widget.RelativeLayout;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import java.io.FileNotFoundException;
 import java.util.Hashtable;
 import java.util.Locale;
 
@@ -1938,6 +1940,23 @@ public class SDLActivity extends Activity implements View.OnSystemUiVisibilityCh
         }
         return 0;
     }
+
+    /**
+     * This method is called by SDL using JNI.
+     */
+    public static int openFileDescriptor(String uri, String mode) throws Exception {
+        if (mSingleton == null) {
+            return -1;
+        }
+
+        try {
+            ParcelFileDescriptor pfd = mSingleton.getContentResolver().openFileDescriptor(Uri.parse(uri), mode);
+            return pfd != null ? pfd.detachFd() : -1;
+        } catch (FileNotFoundException e) {
+            e.printStackTrace();
+            return -1;
+        }
+    }
 }
 
 /**

include/SDL3/SDL_iostream.h

@@ -175,8 +175,9 @@ typedef struct SDL_IOStream SDL_IOStream;
  * This function supports Unicode filenames, but they must be encoded in UTF-8
  * format, regardless of the underlying operating system.
  *
- * As a fallback, SDL_IOFromFile() will transparently open a matching filename
+ * In Android, SDL_IOFromFile() can be used to open content:// URIs. As a
- * in an Android app's `assets`.
+ * fallback, SDL_IOFromFile() will transparently open a matching filename
+ * in the app's `assets`.
  *
  * Closing the SDL_IOStream will close SDL's internal file handle.
  *

src/core/android/SDL_android.c

@@ -345,6 +345,7 @@ static jmethodID midSetWindowStyle;
 static jmethodID midShouldMinimizeOnFocusLoss;
 static jmethodID midShowTextInput;
 static jmethodID midSupportsRelativeMouse;
+static jmethodID midOpenFileDescriptor;
 
 /* audio manager */
 static jclass mAudioManagerClass;
@@ -638,6 +639,7 @@ JNIEXPORT void JNICALL SDL_JAVA_INTERFACE(nativeSetupJNI)(JNIEnv *env, jclass cl
     midShouldMinimizeOnFocusLoss = (*env)->GetStaticMethodID(env, mActivityClass, "shouldMinimizeOnFocusLoss", "()Z");
     midShowTextInput = (*env)->GetStaticMethodID(env, mActivityClass, "showTextInput", "(IIII)Z");
     midSupportsRelativeMouse = (*env)->GetStaticMethodID(env, mActivityClass, "supportsRelativeMouse", "()Z");
+    midOpenFileDescriptor = (*env)->GetStaticMethodID(env, mActivityClass, "openFileDescriptor", "(Ljava/lang/String;Ljava/lang/String;)I");
 
     if (!midClipboardGetText ||
         !midClipboardHasText ||
@@ -667,7 +669,8 @@ JNIEXPORT void JNICALL SDL_JAVA_INTERFACE(nativeSetupJNI)(JNIEnv *env, jclass cl
         !midSetWindowStyle ||
         !midShouldMinimizeOnFocusLoss ||
         !midShowTextInput ||
-        !midSupportsRelativeMouse) {
+        !midSupportsRelativeMouse ||
+        !midOpenFileDescriptor) {
         __android_log_print(ANDROID_LOG_WARN, "SDL", "Missing some Java callbacks, do you have the latest version of SDLActivity.java?");
     }
 
@@ -2766,4 +2769,58 @@ int Android_JNI_OpenURL(const char *url)
     return ret;
 }
 
+int Android_JNI_OpenFileDescriptor(const char *uri, const char *mode)
+{
+    /* Get fopen-style modes */
+    int moderead = 0, modewrite = 0, modeappend = 0, modeupdate = 0;
+
+    for (const char *cmode = mode; *cmode; cmode++) {
+        switch (*cmode) {
+            case 'a':
+                modeappend = 1;
+                break;
+            case 'r':
+                moderead = 1;
+                break;
+            case 'w':
+                modewrite = 1;
+                break;
+            case '+':
+                modeupdate = 1;
+                break;
+            default:
+                break;
+        }
+    }
+
+    /* Translate fopen-style modes to ContentResolver modes. */
+    /* Android only allows "r", "w", "wt", "wa", "rw" or "rwt". */
+    const char *contentResolverMode = "r";
+
+    if (moderead) {
+        if (modewrite) {
+            contentResolverMode = "rwt";
+        } else {
+            contentResolverMode = modeupdate ? "rw" : "r";
+        }
+    } else if (modewrite) {
+        contentResolverMode = modeupdate ? "rwt" : "wt";
+    } else if (modeappend) {
+        contentResolverMode = modeupdate ? "rw" : "wa";
+    }
+
+    JNIEnv *env = Android_JNI_GetEnv();
+    jstring jstringUri = (*env)->NewStringUTF(env, uri);
+    jstring jstringMode = (*env)->NewStringUTF(env, contentResolverMode);
+    jint fd = (*env)->CallStaticIntMethod(env, mActivityClass, midOpenFileDescriptor, jstringUri, jstringMode);
+    (*env)->DeleteLocalRef(env, jstringUri);
+    (*env)->DeleteLocalRef(env, jstringMode);
+
+    if (fd == -1) {
+        SDL_SetError("Unspecified error in JNI");
+    }
+
+    return fd;
+}
+
 #endif /* SDL_PLATFORM_ANDROID */

src/core/android/SDL_android.h

@@ -75,6 +75,7 @@ int Android_JNI_FileClose(void *userdata);
 
 /* Environment support */
 void Android_JNI_GetManifestEnvironmentVariables(void);
+int Android_JNI_OpenFileDescriptor(const char *uri, const char *mode);
 
 /* Clipboard support */
 int Android_JNI_SetClipboardText(const char *text);

src/file/SDL_iostream.c

@@ -54,6 +54,7 @@ struct SDL_IOStream
 #endif /* SDL_PLATFORM_3DS */
 
 #ifdef SDL_PLATFORM_ANDROID
+#include <unistd.h>
 #include "../core/android/SDL_android.h"
 #endif
 
@@ -558,6 +559,22 @@ SDL_IOStream *SDL_IOFromFile(const char *file, const char *mode)
             }
             return SDL_IOFromFP(fp, 1);
         }
+    } else if (SDL_strncmp(file, "content://", 10) == 0) {
+        /* Try opening content:// URI */
+        int fd = Android_JNI_OpenFileDescriptor(file, mode);
+        if (fd == -1) {
+            /* SDL error is already set. */
+            return NULL;
+        }
+
+        FILE *fp = fdopen(fd, mode);
+        if (!fp) {
+            close(fd);
+            SDL_SetError("Unable to open file descriptor (%d) from URI %s", fd, file);
+            return NULL;
+        }
+
+        return SDL_IOFromFP(fp, SDL_TRUE);
     } else {
         /* Try opening it from internal storage if it's a relative path */
         // !!! FIXME: why not just "char path[PATH_MAX];"