Refactor settings processing

Put all Nix configuration flags in a Settings object.

1 files changed, 105 insertions, 96 deletions

diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index a28e08427da5..7dc2e714bc9d 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -10,38 +10,63 @@
 namespace nix {
 
 
-string nixStore = "/UNINIT";
-string nixDataDir = "/UNINIT";
-string nixLogDir = "/UNINIT";
-string nixStateDir = "/UNINIT";
-string nixDBPath = "/UNINIT";
-string nixConfDir = "/UNINIT";
-string nixLibexecDir = "/UNINIT";
-string nixBinDir = "/UNINIT";
+Settings settings;
 
-bool keepFailed = false;
-bool keepGoing = false;
-bool tryFallback = false;
-Verbosity buildVerbosity = lvlError;
-unsigned int maxBuildJobs = 1;
-unsigned int buildCores = 1;
-bool readOnlyMode = false;
-string thisSystem = "unset";
-time_t maxSilentTime = 0;
-time_t buildTimeout = 0;
-Paths substituters;
-bool useBuildHook = true;
-bool printBuildTrace = false;
 
+Settings::Settings()
+{
+    keepFailed = false;
+    keepGoing = false;
+    tryFallback = false;
+    buildVerbosity = lvlError;
+    maxBuildJobs = 1;
+    buildCores = 1;
+    readOnlyMode = false;
+    thisSystem = SYSTEM;
+    maxSilentTime = 0;
+    buildTimeout = 0;
+    useBuildHook = true;
+    printBuildTrace = false;
+    reservedSize = 1024 * 1024;
+    fsyncMetadata = true;
+    useSQLiteWAL = true;
+    syncBeforeRegistering = false;
+    useSubstitutes = true;
+    useChroot = false;
+    dirsInChroot.insert("/dev");
+    dirsInChroot.insert("/dev/pts");
+    impersonateLinux26 = false;
+    keepLog = true;
+    compressLog = true;
+    cacheFailure = false;
+    pollInterval = 5;
+    checkRootReachability = false;
+    gcKeepOutputs = false;
+    gcKeepDerivations = true;
+    autoOptimiseStore = true;
+    envKeepDerivations = false;
+}
 
-static bool settingsRead = false;
-
-typedef std::map<string, Strings> Settings;
 
-static Settings settings;
+void Settings::processEnvironment()
+{
+    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));
+    nixDBPath = getEnv("NIX_DB_DIR", nixStateDir + "/db");
+    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));
 
-/* Overriden settings. */
-Settings settingsCmdline;
+    string subs = getEnv("NIX_SUBSTITUTERS", "default");
+    if (subs == "default") {
+        substituters.push_back(nixLibexecDir + "/nix/substituters/copy-from-other-stores.pl");
+        substituters.push_back(nixLibexecDir + "/nix/substituters/download-using-manifests.pl");
+        substituters.push_back(nixLibexecDir + "/nix/substituters/download-from-binary-cache.pl");
+    } else
+        substituters = tokenizeString(subs, ":");
+}
 
 
 string & at(Strings & ss, unsigned int n)
@@ -52,7 +77,7 @@ string & at(Strings & ss, unsigned int n)
 }
 
 
-static void readSettings()
+void Settings::loadConfFile()
 {
     Path settingsFile = (format("%1%/%2%") % nixConfDir % "nix.conf").str();
     if (!pathExists(settingsFile)) return;
@@ -80,104 +105,88 @@ static void readSettings()
 
         Strings::iterator i = tokens.begin();
         advance(i, 2);
-        settings[name] = Strings(i, tokens.end());
+        settings[name] = concatStringsSep(" ", Strings(i, tokens.end())); // FIXME: slow
     };
-
-    settings.insert(settingsCmdline.begin(), settingsCmdline.end());
-
-    settingsRead = true;
 }
 
 
-Strings querySetting(const string & name, const Strings & def)
+void Settings::set(const string & name, const string & value)
 {
-    if (!settingsRead) readSettings();
-    Settings::iterator i = settings.find(name);
-    return i == settings.end() ? def : i->second;
+    settings[name] = value;
 }
 
 
-string querySetting(const string & name, const string & def)
+void Settings::update()
 {
-    Strings defs;
-    defs.push_back(def);
-
-    Strings value = querySetting(name, defs);
-    if (value.size() != 1)
-        throw Error(format("configuration option `%1%' should not be a list") % name);
-
-    return value.front();
+    get(thisSystem, "system");
+    get(maxBuildJobs, "build-max-jobs");
+    get(buildCores, "build-cores");
+    get(maxSilentTime, "build-max-silent-time");
+    get(buildTimeout, "build-timeout");
+    get(reservedSize, "gc-reserved-space");
+    get(fsyncMetadata, "fsync-metadata");
+    get(useSQLiteWAL, "use-sqlite-wal");
+    get(syncBeforeRegistering, "sync-before-registering");
+    get(useSubstitutes, "build-use-substitutes");
+    get(buildUsersGroup, "build-users-group");
+    get(useChroot, "build-use-chroot");
+    get(dirsInChroot, "build-chroot-dirs");
+    get(impersonateLinux26, "build-impersonate-linux-26");
+    get(keepLog, "build-keep-log");
+    get(compressLog, "build-compress-log");
+    get(cacheFailure, "build-cache-failure");
+    get(pollInterval, "build-poll-interval");
+    get(checkRootReachability, "gc-check-reachability");
+    get(gcKeepOutputs, "gc-keep-outputs");
+    get(gcKeepDerivations, "gc-keep-derivations");
+    get(autoOptimiseStore, "auto-optimise-store");
+    get(envKeepDerivations, "env-keep-derivations");
 }
 
 
-bool queryBoolSetting(const string & name, bool def)
+void Settings::get(string & res, const string & name)
 {
-    string v = querySetting(name, def ? "true" : "false");
-    if (v == "true") return true;
-    else if (v == "false") return false;
-    else throw Error(format("configuration option `%1%' should be either `true' or `false', not `%2%'")
-        % name % v);
+    SettingsMap::iterator i = settings.find(name);
+    if (i == settings.end()) return;
+    res = i->second;
 }
 
 
-unsigned int queryIntSetting(const string & name, unsigned int def)
+void Settings::get(bool & res, const string & name)
 {
-    int n;
-    if (!string2Int(querySetting(name, int2String(def)), n) || n < 0)
-        throw Error(format("configuration setting `%1%' should have an integer value") % name);
-    return n;
-}
-
-
-void overrideSetting(const string & name, const Strings & value)
-{
-    if (settingsRead) settings[name] = value;
-    settingsCmdline[name] = value;
+    SettingsMap::iterator i = settings.find(name);
+    if (i == settings.end()) return;
+    if (i->second == "true") res = true;
+    else if (i->second == "false") res = false;
+    else throw Error(format("configuration option `%1%' should be either `true' or `false', not `%2%'")
+        % name % i->second);
 }
 
 
-void reloadSettings()
+void Settings::get(PathSet & res, const string & name)
 {
-    settingsRead = false;
-    settings.clear();
+    SettingsMap::iterator i = settings.find(name);
+    if (i == settings.end()) return;
+    res.clear();
+    Strings ss = tokenizeString(i->second);
+    res.insert(ss.begin(), ss.end());
 }
 
 
-void setDefaultsFromEnvironment()
+template<class N> void Settings::get(N & res, const string & name)
 {
-    /* Setup Nix paths. */
-    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));
-    nixDBPath = getEnv("NIX_DB_DIR", nixStateDir + "/db");
-    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));
-
-    string subs = getEnv("NIX_SUBSTITUTERS", "default");
-    if (subs == "default") {
-        substituters.push_back(nixLibexecDir + "/nix/substituters/copy-from-other-stores.pl");
-        substituters.push_back(nixLibexecDir + "/nix/substituters/download-using-manifests.pl");
-        substituters.push_back(nixLibexecDir + "/nix/substituters/download-from-binary-cache.pl");
-    } else
-        substituters = tokenizeString(subs, ":");
-
-    /* Get some settings from the configuration file. */
-    thisSystem = querySetting("system", SYSTEM);
-    maxBuildJobs = queryIntSetting("build-max-jobs", 1);
-    buildCores = queryIntSetting("build-cores", 1);
-    maxSilentTime = queryIntSetting("build-max-silent-time", 0);
-    buildTimeout = queryIntSetting("build-timeout", 0);
+    SettingsMap::iterator i = settings.find(name);
+    if (i == settings.end()) return;
+    if (!string2Int(i->second, res))
+        throw Error(format("configuration setting `%1%' should have an integer value") % name);
 }
 
 
-string packSettings()
+string Settings::pack()
 {
     string s;
-    if (!settingsRead) readSettings();
-    foreach (Settings::iterator, i, settings) {
-        s += i->first; s += '='; s += concatStringsSep(" ", i->second); s += '\n';
+    foreach (SettingsMap::iterator, i, settings) {
+        s += i->first; s += '='; s += i->second; s += '\n';
     }
     return s;
 }