libstore: remove DerivationGoal::isReadDesc

all derivation goals need a log fd of some description. let's save this
single fd in a dedicated pointer field for all subclasses so that later
we have just the one spot to change if we turn this into async promises

Change-Id: If223adf90909247363fb823d751cae34d25d0c0b

1 files changed, 7 insertions, 2 deletions

diff --git a/src/libstore/build/derivation-goal.hh b/src/libstore/build/derivation-goal.hh
index 250b437da..da935ceb5 100644
--- a/src/libstore/build/derivation-goal.hh
+++ b/src/libstore/build/derivation-goal.hh
@@ -187,6 +187,13 @@ struct DerivationGoal : public Goal
     std::unique_ptr<HookInstance> hook;
 
     /**
+      * Builder output is pulled from this file descriptor when not null.
+      * Owned by the derivation goal or subclass, must not be reset until
+      * the build has finished and no more output must be processed by us
+      */
+    AutoCloseFD * builderOutFD = nullptr;
+
+    /**
      * The sort of derivation we are building.
      */
     std::optional<DerivationType> derivationType;
@@ -290,8 +297,6 @@ struct DerivationGoal : public Goal
     virtual void cleanupPostOutputsRegisteredModeCheck();
     virtual void cleanupPostOutputsRegisteredModeNonCheck();
 
-    virtual bool isReadDesc(int fd);
-
     /**
      * Callback used by the worker to write to the log.
      */