Recognize IPv6 addresses for "adb connect".

Bug: http://b/22559299
Change-Id: I32891d706b5010c38db84a056e76dd279b780f75
diff --git a/adb/adb_utils.cpp b/adb/adb_utils.cpp
index 4b97a14..e2af045 100644
--- a/adb/adb_utils.cpp
+++ b/adb/adb_utils.cpp
@@ -25,7 +25,9 @@
 
 #include <algorithm>
 
+#include <base/logging.h>
 #include <base/stringprintf.h>
+#include <base/strings.h>
 
 #include "adb_trace.h"
 #include "sysdeps.h"
@@ -103,3 +105,56 @@
 
     DR("%s\n", line.c_str());
 }
+
+bool parse_host_and_port(const std::string& address,
+                         std::string* canonical_address,
+                         std::string* host, int* port,
+                         std::string* error) {
+    host->clear();
+
+    bool ipv6 = true;
+    bool saw_port = false;
+    size_t colons = std::count(address.begin(), address.end(), ':');
+    size_t dots = std::count(address.begin(), address.end(), '.');
+    std::string port_str;
+    if (address[0] == '[') {
+      // [::1]:123
+      if (address.rfind("]:") == std::string::npos) {
+        *error = android::base::StringPrintf("bad IPv6 address '%s'", address.c_str());
+        return false;
+      }
+      *host = address.substr(1, (address.find("]:") - 1));
+      port_str = address.substr(address.rfind("]:") + 2);
+      saw_port = true;
+    } else if (dots == 0 && colons >= 2 && colons <= 7) {
+      // ::1
+      *host = address;
+    } else if (colons <= 1) {
+      // 1.2.3.4 or some.accidental.domain.com
+      ipv6 = false;
+      std::vector<std::string> pieces = android::base::Split(address, ":");
+      *host = pieces[0];
+      if (pieces.size() > 1) {
+        port_str = pieces[1];
+        saw_port = true;
+      }
+    }
+
+    if (host->empty()) {
+      *error = android::base::StringPrintf("no host in '%s'", address.c_str());
+      return false;
+    }
+
+    if (saw_port) {
+      if (sscanf(port_str.c_str(), "%d", port) != 1 || *port <= 0 || *port > 65535) {
+        *error = android::base::StringPrintf("bad port number '%s' in '%s'",
+                                             port_str.c_str(), address.c_str());
+        return false;
+      }
+    }
+
+    *canonical_address = android::base::StringPrintf(ipv6 ? "[%s]:%d" : "%s:%d", host->c_str(), *port);
+    LOG(DEBUG) << "parsed " << address << " as " << *host << " and " << *port
+               << " (" << *canonical_address << ")";
+    return true;
+}