Reset TCP/IP connection with a '+' prefix

When running scrcpy with --tcpip=xx.xx.xx.xx, to make sure a new working
connection is established, it was first disconnected by a call to:

    adb disconnect <addr>

However, this caused all running instances to be killed. Running several
instances of scrcpy on the same device is now useful with virtual
displays, so change the default behavior to NOT disconnect.

To force a reconnection, a '+' prefix can be added:

    scrcpy --tcpip=+192.168.0.x

Fixes #5562 <https://github.com/Genymobile/scrcpy/issues/5562>

app/scrcpy.1

@@ -518,13 +518,15 @@ Enable "show touches" on start, restore the initial value on exit.
 It only shows physical touches (not clicks from scrcpy).
 
 .TP
-.BI "\-\-tcpip\fR[=\fIip\fR[:\fIport\fR]]
-Configure and reconnect the device over TCP/IP.
+.BI "\-\-tcpip\fR[=[+]\fIip\fR[:\fIport\fR]]
+Configure and connect the device over TCP/IP.
 
 If a destination address is provided, then scrcpy connects to this address before starting. The device must listen on the given TCP port (default is 5555).
 
 If no destination address is provided, then scrcpy attempts to find the IP address and adb port of the current device (typically connected over USB), enables TCP/IP mode if necessary, then connects to this address before starting.
 
+Prefix the address with a '+' to force a reconnection.
+
 .TP
 .BI "\-\-time\-limit " seconds
 Set the maximum mirroring time, in seconds.

app/src/adb/adb.c

@@ -412,7 +412,7 @@ sc_adb_connect(struct sc_intr *intr, const char *ip_port, unsigned flags) {
 
     // "adb connect" always returns successfully (with exit code 0), even in
     // case of failure. As a workaround, check if its output starts with
-    // "connected".
+    // "connected" or "already connected".
     char buf[128];
     ssize_t r = sc_pipe_read_all_intr(intr, pid, pout, buf, sizeof(buf) - 1);
     sc_pipe_close(pout);
@@ -429,7 +429,8 @@ sc_adb_connect(struct sc_intr *intr, const char *ip_port, unsigned flags) {
     assert((size_t) r < sizeof(buf));
     buf[r] = '\0';
 
-    ok = !strncmp("connected", buf, sizeof("connected") - 1);
+    ok = !strncmp("connected", buf, sizeof("connected") - 1)
+        || !strncmp("already connected", buf, sizeof("already connected") - 1);
     if (!ok && !(flags & SC_ADB_NO_STDERR)) {
         // "adb connect" also prints errors to stdout. Since we capture it,
         // re-print the error to stderr.

app/src/cli.c

@@ -860,16 +860,17 @@ static const struct sc_option options[] = {
     {
         .longopt_id = OPT_TCPIP,
         .longopt = "tcpip",
-        .argdesc = "ip[:port]",
+        .argdesc = "[+]ip[:port]",
         .optional_arg = true,
-        .text = "Configure and reconnect the device over TCP/IP.\n"
+        .text = "Configure and connect the device over TCP/IP.\n"
                 "If a destination address is provided, then scrcpy connects to "
                 "this address before starting. The device must listen on the "
                 "given TCP port (default is 5555).\n"
                 "If no destination address is provided, then scrcpy attempts "
                 "to find the IP address of the current device (typically "
                 "connected over USB), enables TCP/IP mode, then connects to "
-                "this address before starting.",
+                "this address before starting.\n"
+                "Prefix the address with a '+' to force a reconnection.",
     },
     {
         .longopt_id = OPT_TIME_LIMIT,

app/src/server.c

@@ -829,11 +829,14 @@ sc_server_switch_to_tcpip(struct sc_server *server, const char *serial) {
 }
 
 static bool
-sc_server_connect_to_tcpip(struct sc_server *server, const char *ip_port) {
+sc_server_connect_to_tcpip(struct sc_server *server, const char *ip_port,
+                           bool disconnect) {
     struct sc_intr *intr = &server->intr;
 
-    // Error expected if not connected, do not report any error
-    sc_adb_disconnect(intr, ip_port, SC_ADB_SILENT);
+    if (disconnect) {
+        // Error expected if not connected, do not report any error
+        sc_adb_disconnect(intr, ip_port, SC_ADB_SILENT);
+    }
 
     LOGI("Connecting to %s...", ip_port);
 
@@ -849,7 +852,7 @@ sc_server_connect_to_tcpip(struct sc_server *server, const char *ip_port) {
 
 static bool
 sc_server_configure_tcpip_known_address(struct sc_server *server,
-                                        const char *addr) {
+                                        const char *addr, bool disconnect) {
     // Append ":5555" if no port is present
     bool contains_port = strchr(addr, ':');
     char *ip_port = contains_port ? strdup(addr)
@@ -860,7 +863,7 @@ sc_server_configure_tcpip_known_address(struct sc_server *server,
     }
 
     server->serial = ip_port;
-    return sc_server_connect_to_tcpip(server, ip_port);
+    return sc_server_connect_to_tcpip(server, ip_port, disconnect);
 }
 
 static bool
@@ -885,7 +888,7 @@ sc_server_configure_tcpip_unknown_address(struct sc_server *server,
     }
 
     server->serial = ip_port;
-    return sc_server_connect_to_tcpip(server, ip_port);
+    return sc_server_connect_to_tcpip(server, ip_port, false);
 }
 
 static void
@@ -972,7 +975,13 @@ run_server(void *data) {
             sc_adb_device_destroy(&device);
         }
     } else {
-        ok = sc_server_configure_tcpip_known_address(server, params->tcpip_dst);
+        // If the user passed a '+' (--tcpip=+ip), then disconnect first
+        const char *tcpip_dst = params->tcpip_dst;
+        bool plus = tcpip_dst[0] == '+';
+        if (plus) {
+            ++tcpip_dst;
+        }
+        ok = sc_server_configure_tcpip_known_address(server, tcpip_dst, plus);
         if (!ok) {
             goto error_connection_failed;
         }

doc/connection.md

@@ -85,6 +85,12 @@ scrcpy --tcpip=192.168.1.1       # default port is 5555
 scrcpy --tcpip=192.168.1.1:5555
 ```
 
+Prefix the address with a '+' to force a reconnection:
+
+```bash
+scrcpy --tcpip=+192.168.1.1
+```
+
 
 ### Manual
 

doc/virtual_display.md

@@ -15,8 +15,10 @@ scrcpy --new-display=/240    # use the main display size and 240 dpi
 
 On some devices, a launcher is available in the virtual display.
 
-When no launcher is available, the virtual display is empty. In that case, you
-must [start an Android app](device.md#start-android-app).
+When no launcher is available (or if is explicitly disabled by
+[`--no-vd-system-decorations`](#system-decorations)), the virtual display is
+empty. In that case, you must [start an Android
+app](device.md#start-android-app).
 
 For example:
 
@@ -24,12 +26,27 @@ For example:
 scrcpy --new-display=1920x1080 --start-app=org.videolan.vlc
 ```
 
+The app may itself be a launcher. For example, to run the open source [Fossify
+Launcher]:
+
+```bash
+scrcpy --new-display=1920x1080 --no-vd-system-decorations --start-app=org.fossify.home
+```
+
+[Fossify Launcher]: https://f-droid.org/en/packages/org.fossify.home/
+
+
 ## System decorations
 
-By default, virtual display system decorations are enabled. But some devices
-might display a broken UI;
+By default, virtual display system decorations are enabled. To disable them, use
+`--no-vd-system-decorations`:
 
-Use `--no-vd-system-decorations` to disable it.
+```
+scrcpy --new-display --no-vd-system-decorations
+```
+
+This is useful for some devices which might display a broken UI, or to disable
+any default launcher UI available in virtual displays.
 
 Note that if no app is started, no content will be rendered, so no video frame
 will be produced at all.

server/src/main/java/com/genymobile/scrcpy/video/SurfaceEncoder.java

@@ -112,8 +112,8 @@ public class SurfaceEncoder implements AsyncProcessor {
                         // The capture might have been closed internally (for example if the camera is disconnected)
                         alive = !stopped.get() && !capture.isClosed();
                     }
-                } catch (IllegalStateException | IllegalArgumentException e) {
-                    Ln.e("Encoding error: " + e.getClass().getName() + ": " + e.getMessage());
+                } catch (IllegalStateException | IllegalArgumentException | IOException e) {
+                    Ln.e("Capture/encoding error: " + e.getClass().getName() + ": " + e.getMessage());
                     if (!prepareRetry(size)) {
                         throw e;
                     }