From 85a72ed28e91f7f918a439c8678254537a374ac7 Mon Sep 17 00:00:00 2001
From: Congcong Kuo <congcong.kuo@gmail.com>
Date: Mon, 20 Oct 2025 15:47:25 +0800
Subject: [PATCH] daemon: Use starts_with() and ends_with() instead of string()
 or hasSuffix()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* nix/libstore/build.cc (DerivationGoal::tryBuildHook): Use starts_with instead
of string()
* nix/libstore/builtins.cc (lookupBuiltinBuilder): Same.
* nix/libstore/builtins.hh (isBuiltin): Same and fix indentation of the file.
* nix/libstore/derivations.cc (DerivationOutput::parseHashInfo, isDerivation):
Same and clean header files.
* nix/libstore/gc.cc (addPermRoot, LocalStore::isActiveTempFile): Same.
* nix/libstore/globals.cc: Same.
* nix/libstore/local-store.cc: Same.
* nix/libstore/misc.cc: Same.
* nix/libstore/store-api.cc (checkStoreName): Same.
* nix/libutil/affinity.cc: Same.
* nix/libutil/archive.cc: Same.
* nix/libutil/spawn.cc: Same.
* nix/libutil/util.{cc, hh} (hasSuffix): Removed.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
---
 nix/libstore/build.cc       |  2 +-
 nix/libstore/builtins.cc    |  2 +-
 nix/libstore/builtins.hh    | 32 ++++++++++++++++----------------
 nix/libstore/derivations.cc |  5 ++---
 nix/libstore/gc.cc          |  6 ++----
 nix/libstore/globals.cc     |  2 --
 nix/libstore/local-store.cc |  2 --
 nix/libstore/misc.cc        |  1 -
 nix/libstore/store-api.cc   |  2 +-
 nix/libutil/affinity.cc     |  2 +-
 nix/libutil/archive.cc      |  2 --
 nix/libutil/spawn.cc        |  1 -
 nix/libutil/util.cc         |  7 -------
 nix/libutil/util.hh         |  4 ----
 14 files changed, 24 insertions(+), 46 deletions(-)

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index bf2e9150d6a25ba6f4015f9a25ae497c632b92f7..b3f9c24983c9cfb902f5d631eff1a70a569377bf 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -1573,7 +1573,7 @@ HookReply DerivationGoal::tryBuildHook()
     string reply;
     while (true) {
         string s = readLine(worker.hook->fromAgent.readSide);
-        if (string(s, 0, 2) == "# ") {
+        if (s.starts_with("# ")) {
             reply = string(s, 2);
             break;
         }
diff --git a/nix/libstore/builtins.cc b/nix/libstore/builtins.cc
index b1a32480b55141b57d1462d306a413660f470419..dc0f68a171a320f18cf2d1beea8064aba6715686 100644
--- a/nix/libstore/builtins.cc
+++ b/nix/libstore/builtins.cc
@@ -65,7 +65,7 @@ static const std::map<std::string, derivationBuilder> builtins =
 
 derivationBuilder lookupBuiltinBuilder(const std::string & name)
 {
-    if (name.substr(0, 8) == "builtin:")
+    if (name.starts_with("builtin:"))
     {
 	auto realName = name.substr(8);
 	auto builder = builtins.find(realName);
diff --git a/nix/libstore/builtins.hh b/nix/libstore/builtins.hh
index 602a5a1c58d0aebbc1401e0143647f431d8ac5eb..d5d09e27bc08997d10735bcd116f3959a0340a96 100644
--- a/nix/libstore/builtins.hh
+++ b/nix/libstore/builtins.hh
@@ -25,20 +25,20 @@
 
 namespace nix {
 
-    inline bool isBuiltin(const Derivation & drv)
-    {
-	return string(drv.builder, 0, 8) == "builtin:";
-    }
-
-    /* Build DRV, which lives at DRVPATH.  */
-    typedef void (*derivationBuilder) (const Derivation &drv,
-				       const std::string &drvPath,
-				       const std::string &output);
-
-    /* Return the built-in builder called BUILDER, or NULL if none was
-       found.  */
-    derivationBuilder lookupBuiltinBuilder(const std::string &builder);
-
-    /* Return the list of supported built-in builder names.  */
-    std::list<std::string> builtinBuilderNames();
+inline bool isBuiltin(const Derivation & drv)
+{
+	return drv.builder.starts_with("builtin:");
+}
+
+/* Build DRV, which lives at DRVPATH.  */
+typedef void (*derivationBuilder) (const Derivation &drv,
+                   const std::string &drvPath,
+				   const std::string &output);
+
+/* Return the built-in builder called BUILDER, or NULL if none was
+   found.  */
+derivationBuilder lookupBuiltinBuilder(const std::string &builder);
+
+/* Return the list of supported built-in builder names.  */
+std::list<std::string> builtinBuilderNames();
 }
diff --git a/nix/libstore/derivations.cc b/nix/libstore/derivations.cc
index c253a2a438a4903614c11b6f8f404ba9f27817c2..f05296702b3e0af40e330f770e589d97c8fab6b8 100644
--- a/nix/libstore/derivations.cc
+++ b/nix/libstore/derivations.cc
@@ -2,7 +2,6 @@
 #include "store-api.hh"
 #include "globals.hh"
 #include "util.hh"
-#include "misc.hh"
 
 #include <format>
 
@@ -16,7 +15,7 @@ void DerivationOutput::parseHashInfo(bool & recursive, HashType & hashType, Hash
     recursive = false;
     string algo = hashAlgo;
 
-    if (string(algo, 0, 2) == "r:") {
+    if (algo.starts_with("r:")) {
         recursive = true;
         algo = string(algo, 2);
     }
@@ -200,7 +199,7 @@ string unparseDerivation(const Derivation & drv)
 
 bool isDerivation(const string & fileName)
 {
-    return hasSuffix(fileName, drvExtension);
+    return fileName.ends_with(drvExtension);
 }
 
 
diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
index 96440077fb5be507972095c282604c6ea9c09862..efb9fd52cbbea19ce71e8478759bcbf71f155498 100644
--- a/nix/libstore/gc.cc
+++ b/nix/libstore/gc.cc
@@ -2,8 +2,6 @@
 #include "misc.hh"
 #include "local-store.hh"
 
-#include <functional>
-#include <queue>
 #include <random>
 #include <algorithm>
 #include <format>
@@ -108,7 +106,7 @@ Path addPermRoot(StoreAPI & store, const Path & _storePath,
         if (!allowOutsideRootsDir) {
             Path rootsDir = canonPath(std::format("{}/{}", settings.nixStateDir, gcRootsDir));
 
-            if (string(gcRoot, 0, rootsDir.size() + 1) != rootsDir + "/")
+            if (gcRoot.starts_with(rootsDir + "/"))
                 throw Error(std::format(
                     "path `{}' is not a valid garbage collector root; "
                     "it's not in the directory `{}'",
@@ -383,7 +381,7 @@ struct LocalStore::GCState
 bool LocalStore::isActiveTempFile(const GCState & state,
     const Path & path, const string & suffix)
 {
-    return hasSuffix(path, suffix)
+    return path.ends_with(suffix)
         && state.tempRoots.find(string(path, 0, path.size() - suffix.size())) != state.tempRoots.end();
 }
 
diff --git a/nix/libstore/globals.cc b/nix/libstore/globals.cc
index 16f43f6abcbe6f723c434c7765e2d3c67e146fdb..8551fea56c01417b227adcca89317171d504a53d 100644
--- a/nix/libstore/globals.cc
+++ b/nix/libstore/globals.cc
@@ -2,10 +2,8 @@
 
 #include "globals.hh"
 #include "util.hh"
-#include "archive.hh"
 
 #include <map>
-#include <algorithm>
 #include <format>
 
 namespace nix {
diff --git a/nix/libstore/local-store.cc b/nix/libstore/local-store.cc
index f11f48bcf078d07965593ece2a0d9812d8130131..161c8d81bdae48ff99403b46aa15dea0aad5f293 100644
--- a/nix/libstore/local-store.cc
+++ b/nix/libstore/local-store.cc
@@ -5,9 +5,7 @@
 #include "pathlocks.hh"
 #include "worker-protocol.hh"
 #include "derivations.hh"
-#include "affinity.hh"
 
-#include <iostream>
 #include <algorithm>
 #include <format>
 #include <cstring>
diff --git a/nix/libstore/misc.cc b/nix/libstore/misc.cc
index 943fb9c9719e765cf9b3ded8e35f2ae32ebfc806..88a24d4b822473687ef8ea999f36a88f60dce593 100644
--- a/nix/libstore/misc.cc
+++ b/nix/libstore/misc.cc
@@ -2,7 +2,6 @@
 #include <math.h>
 #include "store-api.hh"
 #include "local-store.hh"
-#include "globals.hh"
 
 #include <format>
 
diff --git a/nix/libstore/store-api.cc b/nix/libstore/store-api.cc
index 0596678b8b5fbdb748aa6dc8d62bb503770ead1b..1067e44a8e2b97c736891e1449d4732cc9646c72 100644
--- a/nix/libstore/store-api.cc
+++ b/nix/libstore/store-api.cc
@@ -60,7 +60,7 @@ void checkStoreName(const string & name)
     string validChars = "+-._?=";
     /* Disallow names starting with a dot for possible security
        reasons (e.g., "." and ".."). */
-    if (string(name, 0, 1) == ".")
+    if (name.starts_with("."))
         throw Error(std::format("invalid name: `{}' (can't begin with dot)", name));
     for (const auto& i : name)
         if (!((i >= 'A' && i <= 'Z') ||
diff --git a/nix/libutil/affinity.cc b/nix/libutil/affinity.cc
index d50e9f3e9cdc5c999e1f39bdef9689b6b3b34d1f..53500c22ab90aca8cbf6bb6d8fb75d9801fd36ca 100644
--- a/nix/libutil/affinity.cc
+++ b/nix/libutil/affinity.cc
@@ -3,7 +3,7 @@
 #include "affinity.hh"
 
 #include <format>
- 
+
 #if HAVE_SCHED_H
 #include <sched.h>
 #endif
diff --git a/nix/libutil/archive.cc b/nix/libutil/archive.cc
index 0df5285860be493c55a0f8709b65a23857e4787a..fa9f4398e3c6dfab37720f767d35d35a77f9f504 100644
--- a/nix/libutil/archive.cc
+++ b/nix/libutil/archive.cc
@@ -3,8 +3,6 @@
 #include "config.h"
 
 #include <cerrno>
-#include <algorithm>
-#include <vector>
 #include <map>
 #include <format>
 
diff --git a/nix/libutil/spawn.cc b/nix/libutil/spawn.cc
index c25c3a681f259fd6cb2bbb8f65a5864285989342..02676d65f972ea0fcefb3452659c0874bb5d4d2a 100644
--- a/nix/libutil/spawn.cc
+++ b/nix/libutil/spawn.cc
@@ -29,7 +29,6 @@
 #include <fcntl.h>
 #include <cstring>
 #include <cstdlib>
-#include <cstdint>
 #include <cassert>
 #include <format>
 
diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index ddce9879caccd0feda812a4f2a177d5e52e871e5..22022db51a5c6ff4c106d75d0c7042b98c6b8ad5 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -7,7 +7,6 @@
 #include <cerrno>
 #include <cstdio>
 #include <cstdlib>
-#include <sstream>
 #include <cstring>
 #include <cassert>
 #include <format>
@@ -1343,12 +1342,6 @@ bool statusOk(int status)
 }
 
 
-bool hasSuffix(const string & s, const string & suffix)
-{
-    return s.size() >= suffix.size() && string(s, s.size() - suffix.size()) == suffix;
-}
-
-
 void expect(std::istream & str, std::string_view s)
 {
     std::vector<char> s2(s.size());
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
index d30dc7801e271a7b74be8268188b7fe7d5a55e08..436c378cb6ed2adcffc6cb0b7bd3d8ae4bfba51e 100644
--- a/nix/libutil/util.hh
+++ b/nix/libutil/util.hh
@@ -365,10 +365,6 @@ template<class N> bool string2Int(const string & s, N & n)
 }
 
 
-/* Return true iff `s' ends in `suffix'. */
-bool hasSuffix(const string & s, const string & suffix);
-
-
 /* Read string `s' from stream `str'. */
 void expect(std::istream & str, std::string_view s);