From 464aaab4dbbdfaed0b66fb495ff47b75f87c296f Mon Sep 17 00:00:00 2001
From: Oleg Sidorkin <osidorkin@gmail.com>
Date: Sat, 31 Jan 2026 12:46:13 +0300
Subject: [PATCH] perf: Use copy_file_range to copy files if available (#1680)

---
 cmake/GenerateConfigurationFile.cmake | 1 +
 cmake/config.h.in                     | 3 +++
 src/ccache/util/file.cpp              | 8 +++++++-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/cmake/GenerateConfigurationFile.cmake b/cmake/GenerateConfigurationFile.cmake
index 01522ad9..ad8cce6a 100644
--- a/cmake/GenerateConfigurationFile.cmake
+++ b/cmake/GenerateConfigurationFile.cmake
@@ -25,6 +25,7 @@ endforeach()
 
 include(CheckFunctionExists)
 set(functions
+    copy_file_range
     getopt_long
     getpwuid
     localtime_r
diff --git a/cmake/config.h.in b/cmake/config.h.in
index dfd8e4e3..87dd0322 100644
--- a/cmake/config.h.in
+++ b/cmake/config.h.in
@@ -113,6 +113,9 @@
 
 // === Functions ===
 
+// Define if you have the "copy_file_range" function.
+#cmakedefine HAVE_COPY_FILE_RANGE
+
 // Define if you have the "getopt_long" function.
 #cmakedefine HAVE_GETOPT_LONG
 
diff --git a/src/ccache/util/file.cpp b/src/ccache/util/file.cpp
index 4631eb33..4653e247 100644
--- a/src/ccache/util/file.cpp
+++ b/src/ccache/util/file.cpp
@@ -161,17 +161,23 @@ copy_file_impl(const fs::path& src,
       FMT("Failed to copy {} to {}: {}", src, dest, strerror(errno)));
   }
   return {};
-#  elif defined(HAVE_SYS_SENDFILE_H)
+#  elif defined(HAVE_COPY_FILE_RANGE) || defined(HAVE_SYS_SENDFILE_H)
   DirEntry dir_entry(src, *src_fd);
   if (!dir_entry) {
     return tl::unexpected(FMT("Failed to stat {}: {}", src, strerror(errno)));
   }
   ssize_t bytes_left = dir_entry.size();
   while (bytes_left > 0) {
+#    if defined(HAVE_SYS_SENDFILE_H)
     ssize_t n = sendfile(*dst_fd, *src_fd, nullptr, bytes_left);
+#    elif defined(HAVE_COPY_FILE_RANGE)
+    ssize_t n =
+      copy_file_range(*src_fd, nullptr, *dst_fd, nullptr, bytes_left, 0);
+#    endif
     if (n < 0) {
       switch (errno) {
       case EINVAL:
+      case EXDEV:
       case ENOSYS:
         return copy_fd(*src_fd, *dst_fd);
       default:
-- 
2.47.3