libstore: move logSize into each log handler

there's no need for this to be an instance variable of the goals.

Change-Id: Iaa315e8b5d8649d8eb3c3fedc387c0f0c48945fc

lix/libstore/build/derivation-goal.cc

@@ -23,6 +23,7 @@
 
 #include <boost/outcome/try.hpp>
 #include <capnp/rpc-twoparty.h>
+#include <cstdint>
 #include <fstream>
 #include <kj/array.h>
 #include <kj/async-unix.h>
@@ -1150,8 +1151,6 @@ kj::Promise<Result<SingleDrvOutputs>> DerivationGoal::registerOutputs()
 
 Path DerivationGoal::openLogFile()
 {
-    logSize = 0;
-
     if (!settings.keepLog) return "";
 
     auto baseName = std::string(baseNameOf(worker.store.printStorePath(drvPath)));
@@ -1181,7 +1180,6 @@ Path DerivationGoal::openLogFile()
     return logFileName;
 }
 
-
 void DerivationGoal::closeLogFile()
 {
     auto logSink2 = std::dynamic_pointer_cast<CompressionSink>(logSink);
@@ -1205,6 +1203,7 @@ kj::Promise<Result<std::optional<Goal::WorkResult>>> DerivationGoal::handleRawCh
 try {
     assert(hook);
 
+    uint64_t logSize = 0;
     std::string currentHookLine;
 
     AsyncFdIoStream in(AsyncFdIoStream::shared_fd{}, hook->fromHook.get());

lix/libstore/build/derivation-goal.hh

@@ -191,11 +191,6 @@ struct DerivationGoal : public Goal
     AutoCloseFD fdLogFile;
     std::shared_ptr<BufferedSink> logFileSink, logSink;
 
-    /**
-     * Number of bytes received from the builder's stdout/stderr.
-     */
-    unsigned long logSize;
-
     /**
      * The most recent log lines.
      */

lix/libstore/build/local-derivation-goal.cc

@@ -2699,6 +2699,7 @@ try {
     AsyncFdIoStream in(AsyncFdIoStream::shared_fd{}, builderOutPTY.get());
 
     LogLineSplitter splitter;
+    uint64_t logSize = 0;
 
     auto flushLine = [&](const std::string & line) {
         if (const auto state =