refactor(tvix): Make static strings constexpr string_views r/1791

Make all static std::strings constexpr std::string_views, and replace
concatenation with absl::StrCat where necessary.

Technically all of these are constant, so they really don't need to be
top-level statics - and since I'm trying to get rid of as much global
state as possible in preparation for making the nix daemon properly
multithreaded I figured I'd knock these out while I was at it.

Change-Id: Ibd3ad9ef68f0a0eacb135541b39fdb13dae042e1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1939
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

1 files changed, 3 insertions, 3 deletions

diff --git a/third_party/nix/src/libstore/build.cc b/third_party/nix/src/libstore/build.cc
index a009651c9d96..e50f4cfa9901 100644
--- a/third_party/nix/src/libstore/build.cc
+++ b/third_party/nix/src/libstore/build.cc
@@ -81,7 +81,7 @@
 
 namespace nix {
 
-static std::string pathNullDevice = "/dev/null";
+constexpr std::string_view kPathNullDevice = "/dev/null";
 
 /* Forward definition. */
 class Worker;
@@ -448,9 +448,9 @@ static void commonChildInit(Pipe& logPipe) {
   }
 
   /* Reroute stdin to /dev/null. */
-  int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
+  int fdDevNull = open(kPathNullDevice.begin(), O_RDWR);
   if (fdDevNull == -1) {
-    throw SysError(format("cannot open '%1%'") % pathNullDevice);
+    throw SysError(format("cannot open '%1%'") % kPathNullDevice);
   }
   if (dup2(fdDevNull, STDIN_FILENO) == -1) {
     throw SysError("cannot dup null device into stdin");