libstore: use makeTemp{,Sibling}Path more

Change-Id: I6a6a69641f9c9d3ab339d25d061dad6cd1f8416d

lix/libstore/local-binary-cache-store.cc

@@ -69,8 +69,7 @@ protected:
     ) override
     try {
         auto path2 = binaryCacheDir + "/" + path;
-        static std::atomic<int> counter{0};
-        Path tmp = fmt("%s.tmp.%d.%d", path2, getpid(), ++counter);
+        Path tmp = makeTempPath(path2);
         AutoDelete del(tmp, false);
         StreamToSourceAdapter source(istream);
         writeFile(tmp, source);

lix/libstore/local-store.cc

@@ -1734,7 +1734,7 @@ try {
 
     createDirs(dirOf(logPath));
 
-    auto tmpFile = fmt("%s.tmp.%d", logPath, getpid());
+    auto tmpFile = makeTempSiblingPath(logPath);
 
     writeFile(tmpFile, compress("bzip2", log));
 

lix/libutil/file-system.cc

@@ -711,20 +711,9 @@ void createSymlink(const Path & target, const Path & link)
 
 void replaceSymlink(const Path & target, const Path & link)
 {
-    for (unsigned int n = 0; true; n++) {
-        Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
-
-        try {
-            createSymlink(target, tmp);
-        } catch (SysError & e) {
-            if (e.errNo == EEXIST) continue;
-            throw;
-        }
-
-        renameFile(tmp, link);
-
-        break;
-    }
+    Path tmp = canonPath(makeTempSiblingPath(link));
+    createSymlink(target, tmp);
+    renameFile(tmp, link);
 }
 
 void setWriteTime(const fs::path & p, const struct stat & st)