daemon: Run 'guix substitute' directly and assume a single substituter.

The daemon had a mechanism that allows it to handle a list of
substituters and try them sequentially; this removes it.

* nix/scripts/substitute.in: Remove.
* nix/local.mk (nodist_pkglibexec_SCRIPTS): Remove.
* config-daemon.ac: Don't output 'nix/scripts/substitute'.
* nix/libstore/build.cc (SubstitutionGoal)[subs, sub, hasSubstitute]:
Remove.
[tryNext]: Make private.
(SubstitutionGoal::SubstitutionGoal, SubstitutionGoal::init): Remove now
unneeded initializers.
(SubstitutionGoal::tryNext): Adjust to assume a single substituter: call
'amDone' upfront when we couldn't find substitutes.
(SubstitutionGoal::tryToRun): Adjust to run 'guix substitute' via
'settings.guixProgram'.
(SubstitutionGoal::finished): Call 'amDone(ecFailed)' upon failure
instead of setting 'state' to 'tryNext'.
* nix/libstore/globals.hh (Settings)[substituters]: Remove.
* nix/libstore/local-store.cc (LocalStore::~LocalStore): Adjust to
handle a single substituter.
(LocalStore::startSubstituter): Remove 'path' parameter.  Adjust to
invoke 'settings.guixProgram'.  Don't refer to 'run.program', which no
longer exists.
(LocalStore::querySubstitutablePaths): Adjust for 'runningSubstituters'
being a singleton instead of a list.
(LocalStore::querySubstitutablePathInfos): Likewise, and remove
'substituter' parameter.
* nix/libstore/local-store.hh (RunningSubstituter)[program]: Remove.
(LocalStore)[runningSubstituters]: Remove.
[runningSubstituter]: New field.
[querySubstitutablePathInfos]: Remove 'substituter' parameter.
[startSubstituter]: Remove 'substituter' parameter.
* nix/nix-daemon/guix-daemon.cc (main): Remove references to
'settings.substituters'.
* nix/nix-daemon/nix-daemon.cc (performOp): Ignore the user's
"build-use-substitutes" value when 'settings.useSubstitutes' is false.

1 files changed, 5 insertions, 7 deletions

diff --git a/nix/libstore/local-store.hh b/nix/libstore/local-store.hh
index 4e6b4cfc1d..4113fafcb5 100644
--- a/nix/libstore/local-store.hh
+++ b/nix/libstore/local-store.hh
@@ -40,7 +40,6 @@ struct OptimiseStats
 
 struct RunningSubstituter
 {
-    Path program;
     Pid pid;
     AutoCloseFD to, from, error;
     FdSource fromBuf;
@@ -52,8 +51,8 @@ struct RunningSubstituter
 class LocalStore : public StoreAPI
 {
 private:
-    typedef std::map<Path, RunningSubstituter> RunningSubstituters;
-    RunningSubstituters runningSubstituters;
+    /* The currently running substituter or empty.  */
+    std::unique_ptr<RunningSubstituter> runningSubstituter;
 
     Path linksDir;
 
@@ -93,8 +92,8 @@ public:
 
     PathSet querySubstitutablePaths(const PathSet & paths);
 
-    void querySubstitutablePathInfos(const Path & substituter,
-        PathSet & paths, SubstitutablePathInfos & infos);
+    void querySubstitutablePathInfos(PathSet & paths,
+        SubstitutablePathInfos & infos);
 
     void querySubstitutablePathInfos(const PathSet & paths,
         SubstitutablePathInfos & infos);
@@ -261,8 +260,7 @@ private:
 
     void removeUnusedLinks(const GCState & state);
 
-    void startSubstituter(const Path & substituter,
-        RunningSubstituter & runningSubstituter);
+    void startSubstituter(RunningSubstituter & runningSubstituter);
 
     string getLineFromSubstituter(RunningSubstituter & run);