Fix meizu 16th NPE

Fill AppInfo to avoid NullPointerException on some devices.

Fixes <https://github.com/Genymobile/scrcpy/issues/365>

Signed-off-by: Romain Vimont <rom@rom1v.com>

app/src/scrcpy.c

@@ -144,12 +144,7 @@ handle_event(SDL_Event *event, bool control) {
             }
             break;
         case SDL_WINDOWEVENT:
-            switch (event->window.event) {
-                case SDL_WINDOWEVENT_EXPOSED:
-                case SDL_WINDOWEVENT_SIZE_CHANGED:
-                    screen_render(&screen);
-                    break;
-            }
+            screen_handle_window_event(&screen, &event->window);
             break;
         case SDL_TEXTINPUT:
             if (!control) {

app/src/screen.c

@@ -30,23 +30,28 @@ get_window_size(SDL_Window *window) {
 // get the windowed window size
 static struct size
 get_windowed_window_size(const struct screen *screen) {
-    if (screen->fullscreen) {
+    if (screen->fullscreen || screen->maximized) {
         return screen->windowed_window_size;
     }
     return get_window_size(screen->window);
 }
 
+// apply the windowed window size if fullscreen and maximized are disabled
+static void
+apply_windowed_size(struct screen *screen) {
+    if (!screen->fullscreen && !screen->maximized) {
+        SDL_SetWindowSize(screen->window, screen->windowed_window_size.width,
+                                          screen->windowed_window_size.height);
+    }
+}
+
 // set the window size to be applied when fullscreen is disabled
 static void
 set_window_size(struct screen *screen, struct size new_size) {
     // setting the window size during fullscreen is implementation defined,
     // so apply the resize only after fullscreen is disabled
-    if (screen->fullscreen) {
-        // SDL_SetWindowSize will be called when fullscreen will be disabled
-        screen->windowed_window_size = new_size;
-    } else {
-        SDL_SetWindowSize(screen->window, new_size.width, new_size.height);
-    }
+    screen->windowed_window_size = new_size;
+    apply_windowed_size(screen);
 }
 
 // get the preferred display bounds (i.e. the screen bounds with some margins)
@@ -194,6 +199,8 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         return false;
     }
 
+    screen->windowed_window_size = window_size;
+
     return true;
 }
 
@@ -287,10 +294,6 @@ screen_render(struct screen *screen) {
 
 void
 screen_switch_fullscreen(struct screen *screen) {
-    if (!screen->fullscreen) {
-        // going to fullscreen, store the current windowed window size
-        screen->windowed_window_size = get_window_size(screen->window);
-    }
     uint32_t new_mode = screen->fullscreen ? 0 : SDL_WINDOW_FULLSCREEN_DESKTOP;
     if (SDL_SetWindowFullscreen(screen->window, new_mode)) {
         LOGW("Could not switch fullscreen mode: %s", SDL_GetError());
@@ -298,11 +301,7 @@ screen_switch_fullscreen(struct screen *screen) {
     }
 
     screen->fullscreen = !screen->fullscreen;
-    if (!screen->fullscreen) {
-        // fullscreen disabled, restore expected windowed window size
-        SDL_SetWindowSize(screen->window, screen->windowed_window_size.width,
-                          screen->windowed_window_size.height);
-    }
+    apply_windowed_size(screen);
 
     LOGD("Switched to %s mode", screen->fullscreen ? "fullscreen" : "windowed");
     screen_render(screen);
@@ -310,20 +309,75 @@ screen_switch_fullscreen(struct screen *screen) {
 
 void
 screen_resize_to_fit(struct screen *screen) {
-    if (!screen->fullscreen) {
-        struct size optimal_size = get_optimal_window_size(screen,
-                                                           screen->frame_size);
-        SDL_SetWindowSize(screen->window, optimal_size.width,
-                          optimal_size.height);
-        LOGD("Resized to optimal size");
+    if (screen->fullscreen) {
+        return;
     }
+
+    if (screen->maximized) {
+        SDL_RestoreWindow(screen->window);
+        screen->maximized = false;
+    }
+
+    struct size optimal_size =
+        get_optimal_window_size(screen, screen->frame_size);
+    SDL_SetWindowSize(screen->window, optimal_size.width, optimal_size.height);
+    LOGD("Resized to optimal size");
 }
 
 void
 screen_resize_to_pixel_perfect(struct screen *screen) {
-    if (!screen->fullscreen) {
-        SDL_SetWindowSize(screen->window, screen->frame_size.width,
-                          screen->frame_size.height);
-        LOGD("Resized to pixel-perfect");
+    if (screen->fullscreen) {
+        return;
+    }
+
+    if (screen->maximized) {
+        SDL_RestoreWindow(screen->window);
+        screen->maximized = false;
+    }
+
+    SDL_SetWindowSize(screen->window, screen->frame_size.width,
+                      screen->frame_size.height);
+    LOGD("Resized to pixel-perfect");
+}
+
+void
+screen_handle_window_event(struct screen *screen,
+                           const SDL_WindowEvent *event) {
+    switch (event->event) {
+        case SDL_WINDOWEVENT_EXPOSED:
+            screen_render(screen);
+            break;
+        case SDL_WINDOWEVENT_SIZE_CHANGED:
+            if (!screen->fullscreen && !screen->maximized) {
+                // Backup the previous size: if we receive the MAXIMIZED event,
+                // then the new size must be ignored (it's the maximized size).
+                // We could not rely on the window flags due to race conditions
+                // (they could be updated asynchronously, at least on X11).
+                screen->windowed_window_size_backup =
+                    screen->windowed_window_size;
+
+                // Save the windowed size, so that it is available once the
+                // window is maximized or fullscreen is enabled.
+                screen->windowed_window_size = get_window_size(screen->window);
+            }
+            screen_render(screen);
+            break;
+        case SDL_WINDOWEVENT_MAXIMIZED:
+            // The backup size must be non-nul.
+            SDL_assert(screen->windowed_window_size_backup.width);
+            SDL_assert(screen->windowed_window_size_backup.height);
+            // Revert the last size, it was updated while screen was maximized.
+            screen->windowed_window_size = screen->windowed_window_size_backup;
+#ifdef DEBUG
+            // Reset the backup to invalid values to detect unexpected usage
+            screen->windowed_window_size_backup.width = 0;
+            screen->windowed_window_size_backup.height = 0;
+#endif
+            screen->maximized = true;
+            break;
+        case SDL_WINDOWEVENT_RESTORED:
+            screen->maximized = false;
+            apply_windowed_size(screen);
+            break;
     }
 }

app/src/screen.h

@@ -15,28 +15,37 @@ struct screen {
     SDL_Renderer *renderer;
     SDL_Texture *texture;
     struct size frame_size;
-    //used only in fullscreen mode to know the windowed window size
+    // The window size the last time it was not maximized or fullscreen.
     struct size windowed_window_size;
+    // Since we receive the event SIZE_CHANGED before MAXIMIZED, we must be
+    // able to revert the size to its non-maximized value.
+    struct size windowed_window_size_backup;
     bool has_frame;
     bool fullscreen;
+    bool maximized;
     bool no_window;
 };
 
-#define SCREEN_INITIALIZER {  \
-    .window = NULL,           \
-    .renderer = NULL,         \
-    .texture = NULL,          \
-    .frame_size = {           \
-        .width = 0,           \
-        .height = 0,          \
-    },                        \
+#define SCREEN_INITIALIZER { \
+    .window = NULL, \
+    .renderer = NULL, \
+    .texture = NULL, \
+    .frame_size = { \
+        .width = 0,  \
+        .height = 0, \
+    }, \
     .windowed_window_size = { \
-        .width = 0,           \
-        .height = 0,          \
-    },                        \
-    .has_frame = false,   \
-    .fullscreen = false,  \
-    .no_window = false,   \
+        .width = 0, \
+        .height = 0, \
+    }, \
+    .windowed_window_size_backup = { \
+        .width = 0, \
+        .height = 0, \
+    }, \
+    .has_frame = false, \
+    .fullscreen = false, \
+    .maximized = false, \
+    .no_window = false, \
 }
 
 // initialize default values
@@ -76,4 +85,8 @@ screen_resize_to_fit(struct screen *screen);
 void
 screen_resize_to_pixel_perfect(struct screen *screen);
 
+// react to window events
+void
+screen_handle_window_event(struct screen *screen, const SDL_WindowEvent *event);
+
 #endif

app/src/server.c

@@ -131,6 +131,7 @@ execute_server(struct server *server, const struct server_params *params) {
 #endif
         "/", // unused
         "com.genymobile.scrcpy.Server",
+        SCRCPY_VERSION,
         max_size_string,
         bit_rate_string,
         server->tunnel_forward ? "true" : "false",

server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java

@@ -7,7 +7,6 @@ import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
 import android.media.MediaFormat;
 import android.os.IBinder;
-import android.os.Looper;
 import android.view.Surface;
 
 import java.io.FileDescriptor;
@@ -55,15 +54,8 @@ public class ScreenEncoder implements Device.RotationListener {
     }
 
     public void streamScreen(Device device, FileDescriptor fd) throws IOException {
-        // Some devices internally create a Handler when creating an input Surface, causing an exception:
-        //   "Can't create handler inside thread that has not called Looper.prepare()"
-        // <https://github.com/Genymobile/scrcpy/issues/240>
-        //
-        // Use Looper.prepareMainLooper() instead of Looper.prepare() to avoid a NullPointerException:
-        //   "Attempt to read from field 'android.os.MessageQueue android.os.Looper.mQueue'
-        //    on a null object reference"
-        // <https://github.com/Genymobile/scrcpy/issues/921>
-        Looper.prepareMainLooper();
+        Workarounds.prepareMainLooper();
+        Workarounds.fillAppInfo();
 
         MediaFormat format = createFormat(bitRate, frameRate, iFrameInterval);
         device.setRotationListener(this);

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -67,29 +67,39 @@ public final class Server {
 
     @SuppressWarnings("checkstyle:MagicNumber")
     private static Options createOptions(String... args) {
-        if (args.length != 6) {
-            throw new IllegalArgumentException("Expecting 6 parameters");
+        if (args.length < 1) {
+            throw new IllegalArgumentException("Missing client version");
+        }
+
+        String clientVersion = args[0];
+        if (!clientVersion.equals(BuildConfig.VERSION_NAME)) {
+            throw new IllegalArgumentException("The server version (" + clientVersion + ") does not match the client "
+                    + "(" + BuildConfig.VERSION_NAME + ")");
+        }
+
+        if (args.length != 7) {
+            throw new IllegalArgumentException("Expecting 7 parameters");
         }
 
         Options options = new Options();
 
-        int maxSize = Integer.parseInt(args[0]) & ~7; // multiple of 8
+        int maxSize = Integer.parseInt(args[1]) & ~7; // multiple of 8
         options.setMaxSize(maxSize);
 
-        int bitRate = Integer.parseInt(args[1]);
+        int bitRate = Integer.parseInt(args[2]);
         options.setBitRate(bitRate);
 
         // use "adb forward" instead of "adb tunnel"? (so the server must listen)
-        boolean tunnelForward = Boolean.parseBoolean(args[2]);
+        boolean tunnelForward = Boolean.parseBoolean(args[3]);
         options.setTunnelForward(tunnelForward);
 
-        Rect crop = parseCrop(args[3]);
+        Rect crop = parseCrop(args[4]);
         options.setCrop(crop);
 
-        boolean sendFrameMeta = Boolean.parseBoolean(args[4]);
+        boolean sendFrameMeta = Boolean.parseBoolean(args[5]);
         options.setSendFrameMeta(sendFrameMeta);
 
-        boolean control = Boolean.parseBoolean(args[5]);
+        boolean control = Boolean.parseBoolean(args[6]);
         options.setControl(control);
 
         return options;

server/src/main/java/com/genymobile/scrcpy/Workarounds.java

@@ -0,0 +1,64 @@
+package com.genymobile.scrcpy;
+
+import android.annotation.SuppressLint;
+import android.content.pm.ApplicationInfo;
+import android.os.Looper;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+
+public final class Workarounds {
+    private Workarounds() {
+        // not instantiable
+    }
+
+    public static void prepareMainLooper() {
+        // Some devices internally create a Handler when creating an input Surface, causing an exception:
+        //   "Can't create handler inside thread that has not called Looper.prepare()"
+        // <https://github.com/Genymobile/scrcpy/issues/240>
+        //
+        // Use Looper.prepareMainLooper() instead of Looper.prepare() to avoid a NullPointerException:
+        //   "Attempt to read from field 'android.os.MessageQueue android.os.Looper.mQueue'
+        //    on a null object reference"
+        // <https://github.com/Genymobile/scrcpy/issues/921>
+        Looper.prepareMainLooper();
+    }
+
+    @SuppressLint("PrivateApi")
+    public static void fillAppInfo() {
+        try {
+            // ActivityThread activityThread = new ActivityThread();
+            Class<?> activityThreadClass = Class.forName("android.app.ActivityThread");
+            Constructor<?> activityThreadConstructor = activityThreadClass.getDeclaredConstructor();
+            activityThreadConstructor.setAccessible(true);
+            Object activityThread = activityThreadConstructor.newInstance();
+
+            // ActivityThread.sCurrentActivityThread = activityThread;
+            Field sCurrentActivityThreadField = activityThreadClass.getDeclaredField("sCurrentActivityThread");
+            sCurrentActivityThreadField.setAccessible(true);
+            sCurrentActivityThreadField.set(null, activityThread);
+
+            // ActivityThread.AppBindData appBindData = new ActivityThread.AppBindData();
+            Class<?> appBindDataClass = Class.forName("android.app.ActivityThread$AppBindData");
+            Constructor<?> appBindDataConstructor = appBindDataClass.getDeclaredConstructor();
+            appBindDataConstructor.setAccessible(true);
+            Object appBindData = appBindDataConstructor.newInstance();
+
+            ApplicationInfo applicationInfo = new ApplicationInfo();
+            applicationInfo.packageName = "com.genymobile.scrcpy";
+
+            // appBindData.appInfo = applicationInfo;
+            Field appInfo = appBindDataClass.getDeclaredField("appInfo");
+            appInfo.setAccessible(true);
+            appInfo.set(appBindData, applicationInfo);
+
+            // activityThread.mBoundApplication = appBindData;
+            Field mBoundApplicationField = activityThreadClass.getDeclaredField("mBoundApplication");
+            mBoundApplicationField.setAccessible(true);
+            mBoundApplicationField.set(activityThread, appBindData);
+        } catch (Throwable throwable) {
+            // this is a workaround, so failing is not an error
+            Ln.w("Could not fill app info: " + throwable.getMessage());
+        }
+    }
+}