Improve device selection

README.md

@@ -422,7 +422,7 @@ scrcpy -b2M -m800  # short version
 
 #### Multi-devices
 
-If several devices are listed in `adb devices`, you must specify the _serial_:
+If several devices are listed in `adb devices`, you can specify the _serial_:
 
 ```bash
 scrcpy --serial 0123456789abcdef
@@ -436,6 +436,19 @@ scrcpy --serial 192.168.0.1:5555
 scrcpy -s 192.168.0.1:5555  # short version
 ```
 
+If only one device is connected via either USB or TCP/IP, it is possible to
+select it automatically:
+
+```bash
+# Select the only device connected via USB
+scrcpy -d             # like adb -d
+scrcpy --select-usb   # long version
+
+# Select the only device connected via TCP/IP
+scrcpy -e             # like adb -e
+scrcpy --select-tcpip # long version
+```
+
 You can start several instances of _scrcpy_ for several devices.
 
 #### Autostart on device connection

app/meson.build

@@ -1,6 +1,7 @@
 src = [
     'src/main.c',
     'src/adb/adb.c',
+    'src/adb/adb_device.c',
     'src/adb/adb_parser.c',
     'src/adb/adb_tunnel.c',
     'src/cli.c',
@@ -221,6 +222,7 @@ if get_option('buildtype') == 'debug'
     tests = [
         ['test_adb_parser', [
             'tests/test_adb_parser.c',
+            'src/adb/adb_device.c',
             'src/adb/adb_parser.c',
             'src/util/str.c',
             'src/util/strbuf.c',

app/scrcpy.1

@@ -43,6 +43,12 @@ The values are expressed in the device natural orientation (typically, portrait
 .B \-\-max\-size
 value is computed on the cropped size.
 
+.TP
+.B \-d, \-\-select\-usb
+Use USB device (if there is exactly one, like adb -d).
+
+Also see \fB\-e\fR (\fB\-\-select\-tcpip\fR).
+
 .TP
 .BI "\-\-disable-screensaver"
 Disable screensaver while scrcpy is running.
@@ -62,6 +68,12 @@ Add a buffering delay (in milliseconds) before displaying. This increases latenc
 
 Default is 0 (no buffering).
 
+.TP
+.B \-e, \-\-select\-tcpip
+Use TCP/IP device (if there is exactly one, like adb -e).
+
+Also see \fB\-d\fR (\fB\-\-select\-usb\fR).
+
 .TP
 .BI "\-\-encoder " name
 Use a specific MediaCodec encoder (must be a H.264 encoder).

app/src/adb/adb.c

@@ -194,6 +194,14 @@ sc_adb_execute(const char *const argv[], unsigned flags) {
     return sc_adb_execute_p(argv, flags, NULL);
 }
 
+bool
+sc_adb_start_server(struct sc_intr *intr, unsigned flags) {
+    const char *const argv[] = SC_ADB_COMMAND("start-server");
+
+    sc_pid pid = sc_adb_execute(argv, flags);
+    return process_check_success_intr(intr, pid, "adb start-server", flags);
+}
+
 bool
 sc_adb_forward(struct sc_intr *intr, const char *serial, uint16_t local_port,
                const char *device_socket_name, unsigned flags) {
@@ -374,57 +382,252 @@ sc_adb_disconnect(struct sc_intr *intr, const char *ip_port, unsigned flags) {
     return process_check_success_intr(intr, pid, "adb disconnect", flags);
 }
 
-char *
-sc_adb_getprop(struct sc_intr *intr, const char *serial, const char *prop,
-               unsigned flags) {
-    assert(serial);
-    const char *const argv[] =
-        SC_ADB_COMMAND("-s", serial, "shell", "getprop", prop);
+static ssize_t
+sc_adb_list_devices(struct sc_intr *intr, unsigned flags,
+                    struct sc_adb_device *devices, size_t len) {
+    const char *const argv[] = SC_ADB_COMMAND("devices", "-l");
 
     sc_pipe pout;
     sc_pid pid = sc_adb_execute_p(argv, flags, &pout);
     if (pid == SC_PROCESS_NONE) {
-        LOGE("Could not execute \"adb getprop\"");
-        return NULL;
+        LOGE("Could not execute \"adb devices -l\"");
+        return -1;
     }
 
-    char buf[128];
+    char buf[4096];
     ssize_t r = sc_pipe_read_all_intr(intr, pid, pout, buf, sizeof(buf) - 1);
     sc_pipe_close(pout);
 
-    bool ok = process_check_success_intr(intr, pid, "adb getprop", flags);
+    bool ok = process_check_success_intr(intr, pid, "adb devices -l", flags);
     if (!ok) {
-        return NULL;
+        return -1;
     }
 
     if (r == -1) {
-        return NULL;
+        return -1;
     }
 
     assert((size_t) r < sizeof(buf));
+    if (r == sizeof(buf) - 1)  {
+        // The implementation assumes that the output of "adb devices -l" fits
+        // in the buffer in a single pass
+        LOGW("Result of \"adb devices -l\" does not fit in 4Kb. "
+             "Please report an issue.\n");
+        return -1;
+    }
+
+    // It is parsed as a NUL-terminated string
     buf[r] = '\0';
-    size_t len = strcspn(buf, " \r\n");
-    buf[len] = '\0';
 
-    return strdup(buf);
+    // List all devices to the output list directly
+    return sc_adb_parse_devices(buf, devices, len);
+}
+
+static bool
+sc_adb_accept_device(const struct sc_adb_device *device,
+                     const struct sc_adb_device_selector *selector) {
+    switch (selector->type) {
+        case SC_ADB_DEVICE_SELECT_ALL:
+            return true;
+        case SC_ADB_DEVICE_SELECT_SERIAL:
+            assert(selector->serial);
+            char *device_serial_colon = strchr(device->serial, ':');
+            if (device_serial_colon) {
+                // The device serial is an IP:port...
+                char *serial_colon = strchr(selector->serial, ':');
+                if (!serial_colon) {
+                    // But the requested serial has no ':', so only consider
+                    // the IP part of the device serial. This allows to use
+                    // "192.168.1.1" to match any "192.168.1.1:port".
+                    size_t serial_len = strlen(selector->serial);
+                    size_t device_ip_len = device_serial_colon - device->serial;
+                    if (serial_len != device_ip_len) {
+                        // They are not equal, they don't even have the same
+                        // length
+                        return false;
+                    }
+                    return !strncmp(selector->serial, device->serial,
+                                    device_ip_len);
+                }
+            }
+            return !strcmp(selector->serial, device->serial);
+        case SC_ADB_DEVICE_SELECT_USB:
+            return !sc_adb_is_serial_tcpip(device->serial);
+        case SC_ADB_DEVICE_SELECT_TCPIP:
+            return sc_adb_is_serial_tcpip(device->serial);
+        default:
+            assert(!"Missing SC_ADB_DEVICE_SELECT_* handling");
+            break;
+    }
+
+    return false;
+}
+
+static size_t
+sc_adb_devices_select(struct sc_adb_device *devices, size_t len,
+                      const struct sc_adb_device_selector *selector,
+                      size_t *idx_out) {
+    size_t count = 0;
+    for (size_t i = 0; i < len; ++i) {
+        struct sc_adb_device *device = &devices[i];
+        device->selected = sc_adb_accept_device(device, selector);
+        if (device->selected) {
+            if (idx_out && !count) {
+                *idx_out = i;
+            }
+            ++count;
+        }
+    }
+
+    return count;
+}
+
+static void
+sc_adb_devices_log(enum sc_log_level level, struct sc_adb_device *devices,
+                   size_t count) {
+    for (size_t i = 0; i < count; ++i) {
+        struct sc_adb_device *d = &devices[i];
+        const char *selection = d->selected ? "-->" : "   ";
+        const char *type = sc_adb_is_serial_tcpip(d->serial) ? "(tcpip)"
+                                                             : "  (usb)";
+        LOG(level, "    %s %s  %-20s  %16s  %s",
+             selection, type, d->serial, d->state, d->model ? d->model : "");
+    }
+}
+
+static bool
+sc_adb_device_check_state(struct sc_adb_device *device,
+                          struct sc_adb_device *devices, size_t count) {
+    const char *state = device->state;
+
+    if (!strcmp("device", state)) {
+        return true;
+    }
+
+    if (!strcmp("unauthorized", state)) {
+        LOGE("Device is unauthorized:");
+        sc_adb_devices_log(SC_LOG_LEVEL_ERROR, devices, count);
+        LOGE("A popup should open on the device to request authorization.");
+        LOGE("Check the FAQ: "
+             "<https://github.com/Genymobile/scrcpy/blob/master/FAQ.md>");
+    }
+
+    return false;
+}
+
+bool
+sc_adb_select_device(struct sc_intr *intr,
+                     const struct sc_adb_device_selector *selector,
+                     unsigned flags, struct sc_adb_device *out_device) {
+    struct sc_adb_device devices[16];
+    ssize_t count =
+        sc_adb_list_devices(intr, flags, devices, ARRAY_LEN(devices));
+    if (count == -1) {
+        LOGE("Could not list ADB devices");
+        return false;
+    }
+
+    if (count == 0) {
+        LOGE("Could not find any ADB device");
+        return false;
+    }
+
+    size_t sel_idx; // index of the single matching device if sel_count == 1
+    size_t sel_count =
+        sc_adb_devices_select(devices, count, selector, &sel_idx);
+
+    if (sel_count == 0) {
+        // if count > 0 && sel_count == 0, then necessarily a selection is
+        // requested
+        assert(selector->type != SC_ADB_DEVICE_SELECT_ALL);
+
+        switch (selector->type) {
+            case SC_ADB_DEVICE_SELECT_SERIAL:
+                assert(selector->serial);
+                LOGE("Could not find ADB device %s:", selector->serial);
+                break;
+            case SC_ADB_DEVICE_SELECT_USB:
+                LOGE("Could not find any ADB device over USB:");
+                break;
+            case SC_ADB_DEVICE_SELECT_TCPIP:
+                LOGE("Could not find any ADB device over TCP/IP:");
+                break;
+            default:
+                assert(!"Unexpected selector type");
+                break;
+        }
+
+        sc_adb_devices_log(SC_LOG_LEVEL_ERROR, devices, count);
+        sc_adb_devices_destroy_all(devices, count);
+        return false;
+    }
+
+    if (sel_count > 1) {
+        switch (selector->type) {
+            case SC_ADB_DEVICE_SELECT_ALL:
+                LOGE("Multiple (%" SC_PRIsizet ") ADB devices:", sel_count);
+                break;
+            case SC_ADB_DEVICE_SELECT_SERIAL:
+                assert(selector->serial);
+                LOGE("Multiple (%" SC_PRIsizet ") ADB devices with serial %s:",
+                     sel_count, selector->serial);
+                break;
+            case SC_ADB_DEVICE_SELECT_USB:
+                LOGE("Multiple (%" SC_PRIsizet ") ADB devices over USB:",
+                     sel_count);
+                break;
+            case SC_ADB_DEVICE_SELECT_TCPIP:
+                LOGE("Multiple (%" SC_PRIsizet ") ADB devices over TCP/IP:",
+                     sel_count);
+                break;
+            default:
+                assert(!"Unexpected selector type");
+                break;
+        }
+        sc_adb_devices_log(SC_LOG_LEVEL_ERROR, devices, count);
+        LOGE("Select a device via -s (--serial), -d (--select-usb) or -e "
+             "(--select-tcpip)");
+        sc_adb_devices_destroy_all(devices, count);
+        return false;
+    }
+
+    assert(sel_count == 1); // sel_idx is valid only if sel_count == 1
+    struct sc_adb_device *device = &devices[sel_idx];
+
+    bool ok = sc_adb_device_check_state(device, devices, count);
+    if (!ok) {
+        sc_adb_devices_destroy_all(devices, count);
+        return false;
+    }
+
+    LOGD("ADB device found:");
+    sc_adb_devices_log(SC_LOG_LEVEL_DEBUG, devices, count);
+
+    // Move devics into out_device (do not destroy device)
+    sc_adb_device_move(out_device, device);
+    sc_adb_devices_destroy_all(devices, count);
+    return true;
 }
 
 char *
-sc_adb_get_serialno(struct sc_intr *intr, unsigned flags) {
-    const char *const argv[] = SC_ADB_COMMAND("get-serialno");
+sc_adb_getprop(struct sc_intr *intr, const char *serial, const char *prop,
+               unsigned flags) {
+    assert(serial);
+    const char *const argv[] =
+        SC_ADB_COMMAND("-s", serial, "shell", "getprop", prop);
 
     sc_pipe pout;
     sc_pid pid = sc_adb_execute_p(argv, flags, &pout);
     if (pid == SC_PROCESS_NONE) {
-        LOGE("Could not execute \"adb get-serialno\"");
+        LOGE("Could not execute \"adb getprop\"");
         return NULL;
     }
 
     char buf[128];
     ssize_t r = sc_pipe_read_all_intr(intr, pid, pout, buf, sizeof(buf) - 1);
     sc_pipe_close(pout);
 
-    bool ok = process_check_success_intr(intr, pid, "adb get-serialno", flags);
+    bool ok = process_check_success_intr(intr, pid, "adb getprop", flags);
     if (!ok) {
         return NULL;
     }
@@ -482,3 +685,8 @@ sc_adb_get_device_ip(struct sc_intr *intr, const char *serial, unsigned flags) {
 
     return sc_adb_parse_device_ip_from_output(buf);
 }
+
+bool
+sc_adb_is_serial_tcpip(const char *serial) {
+    return strchr(serial, ':');
+}