adb: Recognize rescue mode.

This CL adds client support to recognize the rescue mode (which will be
served by recovery image). It also allows waiting for a device to enter
rescue mode. The support for the actual rescue commands will be added in
follow-up CLs.

Bug: 128415917
Test: `adb devices` recognizes devices under rescue mode.
Test: `adb wait-for-rescue` waits for device to be in rescue mode.
Change-Id: I367d7339fe68006aba09a1e3db6370d472296676

adb/adb.cpp

@@ -280,6 +280,9 @@ void parse_banner(const std::string& banner, atransport* t) {
     } else if (type == "sideload") {
         D("setting connection_state to kCsSideload");
         t->SetConnectionState(kCsSideload);
+    } else if (type == "rescue") {
+        D("setting connection_state to kCsRescue");
+        t->SetConnectionState(kCsRescue);
     } else {
         D("setting connection_state to kCsHost");
         t->SetConnectionState(kCsHost);

adb/adb.h

@@ -107,6 +107,7 @@ enum ConnectionState {
     kCsHost,
     kCsRecovery,
     kCsSideload,
+    kCsRescue,
 };
 
 inline bool ConnectionStateIsOnline(ConnectionState state) {
@@ -116,6 +117,7 @@ inline bool ConnectionStateIsOnline(ConnectionState state) {
         case kCsHost:
         case kCsRecovery:
         case kCsSideload:
+        case kCsRescue:
             return true;
         default:
             return false;

adb/client/commandline.cpp

@@ -190,7 +190,7 @@ static void help() {
         "scripting:\n"
         " wait-for[-TRANSPORT]-STATE\n"
         "     wait for device to be in the given state\n"
-        "     STATE: device, recovery, sideload, bootloader, or disconnect\n"
+        "     STATE: device, recovery, rescue, sideload, bootloader, or disconnect\n"
         "     TRANSPORT: usb, local, or any [default=any]\n"
         " get-state                print offline | bootloader | device\n"
         " get-serialno             print <serial-number>\n"
@@ -1037,11 +1037,12 @@ static bool wait_for_device(const char* service,
     }
 
     if (components[3] != "any" && components[3] != "bootloader" && components[3] != "device" &&
-        components[3] != "recovery" && components[3] != "sideload" &&
+        components[3] != "recovery" && components[3] != "rescue" && components[3] != "sideload" &&
         components[3] != "disconnect") {
         fprintf(stderr,
                 "adb: unknown state %s; "
-                "expected 'any', 'bootloader', 'device', 'recovery', 'sideload', or 'disconnect'\n",
+                "expected 'any', 'bootloader', 'device', 'recovery', 'rescue', 'sideload', or "
+                "'disconnect'\n",
                 components[3].c_str());
         return false;
     }

adb/services.cpp

@@ -227,6 +227,8 @@ asocket* host_service_to_socket(std::string_view name, std::string_view serial,
             sinfo->state = kCsDevice;
         } else if (name == "-recovery") {
             sinfo->state = kCsRecovery;
+        } else if (name == "-rescue") {
+            sinfo->state = kCsRescue;
         } else if (name == "-sideload") {
             sinfo->state = kCsSideload;
         } else if (name == "-bootloader") {

adb/transport.cpp

@@ -1012,6 +1012,8 @@ std::string atransport::connection_state_name() const {
             return "host";
         case kCsRecovery:
             return "recovery";
+        case kCsRescue:
+            return "rescue";
         case kCsNoPerm:
             return UsbNoPermissionsShortHelpText();
         case kCsSideload: