From 34534a9653fd2308f7b04863f28bb71b741a1890 Mon Sep 17 00:00:00 2001
From: Ilya Fedin <fedin-ilja2010@ya.ru>
Date: Thu, 11 Mar 2021 13:11:46 +0400
Subject: [PATCH] Use kernel accelerated sendfile to copy files on Linux

---
 Telegram/SourceFiles/_other/updater_linux.cpp | 20 ++++++++++++----
 .../platform/linux/specific_linux.cpp         | 23 +++++++++++++++----
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/Telegram/SourceFiles/_other/updater_linux.cpp b/Telegram/SourceFiles/_other/updater_linux.cpp
index 5d4d742e2f..911dab048d 100644
--- a/Telegram/SourceFiles/_other/updater_linux.cpp
+++ b/Telegram/SourceFiles/_other/updater_linux.cpp
@@ -97,11 +97,6 @@ bool copyFile(const char *from, const char *to) {
 		fclose(ffrom);
 		return false;
 	}
-	static const int BufSize = 65536;
-	char buf[BufSize];
-	while (size_t size = fread(buf, 1, BufSize, ffrom)) {
-		fwrite(buf, 1, size, fto);
-	}
 
 	struct stat fst; // from http://stackoverflow.com/questions/5486774/keeping-fileowner-and-permissions-after-copying-file-in-c
 	//let's say this wont fail since you already worked OK on that fp
@@ -110,6 +105,21 @@ bool copyFile(const char *from, const char *to) {
 		fclose(fto);
 		return false;
 	}
+
+	ssize_t copied = sendfile(
+		fileno(ffrom),
+		fileno(fto),
+		nullptr,
+		fst.st_size);
+
+	if (copied == -1) {
+		static const int BufSize = 65536;
+		char buf[BufSize];
+		while (size_t size = fread(buf, 1, BufSize, ffrom)) {
+			fwrite(buf, 1, size, fto);
+		}
+	}
+
 	//update to the same uid/gid
 	if (fchown(fileno(fto), fst.st_uid, fst.st_gid) != 0) {
 		fclose(ffrom);
diff --git a/Telegram/SourceFiles/platform/linux/specific_linux.cpp b/Telegram/SourceFiles/platform/linux/specific_linux.cpp
index 32b0a150d9..43e523f599 100644
--- a/Telegram/SourceFiles/platform/linux/specific_linux.cpp
+++ b/Telegram/SourceFiles/platform/linux/specific_linux.cpp
@@ -1022,11 +1022,6 @@ bool linuxMoveFile(const char *from, const char *to) {
 		fclose(ffrom);
 		return false;
 	}
-	static const int BufSize = 65536;
-	char buf[BufSize];
-	while (size_t size = fread(buf, 1, BufSize, ffrom)) {
-		fwrite(buf, 1, size, fto);
-	}
 
 	struct stat fst; // from http://stackoverflow.com/questions/5486774/keeping-fileowner-and-permissions-after-copying-file-in-c
 	//let's say this wont fail since you already worked OK on that fp
@@ -1035,6 +1030,24 @@ bool linuxMoveFile(const char *from, const char *to) {
 		fclose(fto);
 		return false;
 	}
+
+	ssize_t copied = -1;
+#ifdef Q_OS_LINUX
+	copied = sendfile(
+		fileno(ffrom),
+		fileno(fto),
+		nullptr,
+		fst.st_size);
+#endif // Q_OS_LINUX
+	
+	if (copied == -1) {
+		static const int BufSize = 65536;
+		char buf[BufSize];
+		while (size_t size = fread(buf, 1, BufSize, ffrom)) {
+			fwrite(buf, 1, size, fto);
+		}
+	}
+
 	//update to the same uid/gid
 	if (fchown(fileno(fto), fst.st_uid, fst.st_gid) != 0) {
 		fclose(ffrom);