getEnv(): Return std::optional

This allows distinguishing between an empty value and no value.

1 files changed, 11 insertions, 11 deletions

diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index 249c36673..aa0823f41 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -32,20 +32,20 @@ static GlobalConfig::Register r1(&settings);
 
 Settings::Settings()
     : nixPrefix(NIX_PREFIX)
-    , nixStore(canonPath(getEnv("NIX_STORE_DIR", getEnv("NIX_STORE", NIX_STORE_DIR))))
-    , nixDataDir(canonPath(getEnv("NIX_DATA_DIR", NIX_DATA_DIR)))
-    , nixLogDir(canonPath(getEnv("NIX_LOG_DIR", NIX_LOG_DIR)))
-    , nixStateDir(canonPath(getEnv("NIX_STATE_DIR", NIX_STATE_DIR)))
-    , nixConfDir(canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR)))
-    , nixLibexecDir(canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR)))
-    , nixBinDir(canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR)))
+    , nixStore(canonPath(getEnv("NIX_STORE_DIR").value_or(getEnv("NIX_STORE").value_or(NIX_STORE_DIR))))
+    , nixDataDir(canonPath(getEnv("NIX_DATA_DIR").value_or(NIX_DATA_DIR)))
+    , nixLogDir(canonPath(getEnv("NIX_LOG_DIR").value_or(NIX_LOG_DIR)))
+    , nixStateDir(canonPath(getEnv("NIX_STATE_DIR").value_or(NIX_STATE_DIR)))
+    , nixConfDir(canonPath(getEnv("NIX_CONF_DIR").value_or(NIX_CONF_DIR)))
+    , nixLibexecDir(canonPath(getEnv("NIX_LIBEXEC_DIR").value_or(NIX_LIBEXEC_DIR)))
+    , nixBinDir(canonPath(getEnv("NIX_BIN_DIR").value_or(NIX_BIN_DIR)))
     , nixManDir(canonPath(NIX_MAN_DIR))
     , nixDaemonSocketFile(canonPath(nixStateDir + DEFAULT_SOCKET_PATH))
 {
     buildUsersGroup = getuid() == 0 ? "nixbld" : "";
-    lockCPU = getEnv("NIX_AFFINITY_HACK", "1") == "1";
+    lockCPU = getEnv("NIX_AFFINITY_HACK") == "1";
 
-    caFile = getEnv("NIX_SSL_CERT_FILE", getEnv("SSL_CERT_FILE", ""));
+    caFile = getEnv("NIX_SSL_CERT_FILE").value_or(getEnv("SSL_CERT_FILE").value_or(""));
     if (caFile == "") {
         for (auto & fn : {"/etc/ssl/certs/ca-certificates.crt", "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"})
             if (pathExists(fn)) {
@@ -56,9 +56,9 @@ Settings::Settings()
 
     /* Backwards compatibility. */
     auto s = getEnv("NIX_REMOTE_SYSTEMS");
-    if (s != "") {
+    if (s) {
         Strings ss;
-        for (auto & p : tokenizeString<Strings>(s, ":"))
+        for (auto & p : tokenizeString<Strings>(*s, ":"))
             ss.push_back("@" + p);
         builders = concatStringsSep(" ", ss);
     }