adb: add authorizing, connecting states to transport.

Add two states: connecting and authorizing, to disambiguate the offline
and unauthorized states, respectively.

Previously, devices would transition as follows:

  offline -> unauthorized -> offline -> online
  offline -> unauthorized (when actually unauthorized)

With this patch:

  connecting -> authorizing -> online
  connecting -> authorizing -> unauthorized (when actually unauthorized)

This allows test automation and the like to distinguish between offline
devices, unauthorized devices, and working devices without having to
do retry loops with arbitrary sleeps on their end.

Bug: http://b/79257434
Test: adb_test
Test: adbd_test
Test: manually plugging in a device with `while true; do adb shell echo foo; done`
Change-Id: I036d9b593b51a27a59ac3fc57da966fd52658567
diff --git a/adb/transport.cpp b/adb/transport.cpp
index fa7cc8c..be7f8fe 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -708,22 +708,41 @@
     }
     lock.unlock();
 
-    // Don't return unauthorized devices; the caller can't do anything with them.
-    if (result && result->GetConnectionState() == kCsUnauthorized && !accept_any_state) {
-        *error_out = "device unauthorized.\n";
-        char* ADB_VENDOR_KEYS = getenv("ADB_VENDOR_KEYS");
-        *error_out += "This adb server's $ADB_VENDOR_KEYS is ";
-        *error_out += ADB_VENDOR_KEYS ? ADB_VENDOR_KEYS : "not set";
-        *error_out += "\n";
-        *error_out += "Try 'adb kill-server' if that seems wrong.\n";
-        *error_out += "Otherwise check for a confirmation dialog on your device.";
-        result = nullptr;
-    }
+    if (result && !accept_any_state) {
+        // The caller requires an active transport.
+        // Make sure that we're actually connected.
+        ConnectionState state = result->GetConnectionState();
+        switch (state) {
+            case kCsConnecting:
+                *error_out = "device still connecting";
+                result = nullptr;
+                break;
 
-    // Don't return offline devices; the caller can't do anything with them.
-    if (result && result->GetConnectionState() == kCsOffline && !accept_any_state) {
-        *error_out = "device offline";
-        result = nullptr;
+            case kCsAuthorizing:
+                *error_out = "device still authorizing";
+                result = nullptr;
+                break;
+
+            case kCsUnauthorized: {
+                *error_out = "device unauthorized.\n";
+                char* ADB_VENDOR_KEYS = getenv("ADB_VENDOR_KEYS");
+                *error_out += "This adb server's $ADB_VENDOR_KEYS is ";
+                *error_out += ADB_VENDOR_KEYS ? ADB_VENDOR_KEYS : "not set";
+                *error_out += "\n";
+                *error_out += "Try 'adb kill-server' if that seems wrong.\n";
+                *error_out += "Otherwise check for a confirmation dialog on your device.";
+                result = nullptr;
+                break;
+            }
+
+            case kCsOffline:
+                *error_out = "device offline";
+                result = nullptr;
+                break;
+
+            default:
+                break;
+        }
     }
 
     if (result) {
@@ -802,6 +821,10 @@
             return "sideload";
         case kCsUnauthorized:
             return "unauthorized";
+        case kCsAuthorizing:
+            return "authorizing";
+        case kCsConnecting:
+            return "connecting";
         default:
             return "unknown";
     }
@@ -1080,7 +1103,7 @@
 
 void register_usb_transport(usb_handle* usb, const char* serial, const char* devpath,
                             unsigned writeable) {
-    atransport* t = new atransport((writeable ? kCsOffline : kCsNoPerm));
+    atransport* t = new atransport((writeable ? kCsConnecting : kCsNoPerm));
 
     D("transport: %p init'ing for usb_handle %p (sn='%s')", t, usb, serial ? serial : "");
     init_usb_transport(t, usb);