[adb] Correctly read host/user name on Windows.
Bug: 162111908
Test: On linux/mac:
HOSTNAME="" adb keygen mykey; cat mykey.pub # Also LOGNAME
HOSTNAME="测试" adb keygen mykey; cat mykey.pub
HOSTNAME="test" adb keygen mykey; cat mykey.pub
Test: On Windows:
set COMPUTERNAME=&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub" # Also USERNAME
set COMPUTERNAME=测试&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub"
set COMPUTERNAME=test&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub"
Change-Id: I62c952c511a620286aa4e05b1763361406e9f89a
diff --git a/adb/sysdeps/env.h b/adb/sysdeps/env.h
new file mode 100644
index 0000000..b39b675
--- /dev/null
+++ b/adb/sysdeps/env.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <optional>
+#include <string>
+
+namespace adb {
+namespace sysdeps {
+
+// Attempts to retrieve the environment variable value for |var|. Returns std::nullopt
+// if unset.
+std::optional<std::string> GetEnvironmentVariableUTF8(std::string_view var);
+
+// Gets the host name of the system. Returns empty string on failure.
+std::string GetHostNameUTF8();
+// Gets the current login user. Returns empty string on failure.
+std::string GetLoginNameUTF8();
+
+} // namespace sysdeps
+} // namespace adb