copy_file_range linux syscall (#6010)

2 files changed, 28 insertions, 7 deletions

diff --git a/lib/std/fs/file.zig b/lib/std/fs/file.zig
index 3b79e4e01b..ce71571c9f 100644
--- a/lib/std/fs/file.zig
+++ b/lib/std/fs/file.zig
@@ -607,15 +607,10 @@ pub const File = struct {
         }
     }
 
-    pub const CopyRangeError = PWriteError || PReadError;
+    pub const CopyRangeError = os.CopyFileRangeError;
 
     pub fn copyRange(in: File, in_offset: u64, out: File, out_offset: u64, len: usize) CopyRangeError!usize {
-        // TODO take advantage of copy_file_range OS APIs
-        var buf: [8 * 4096]u8 = undefined;
-        const adjusted_count = math.min(buf.len, len);
-        const amt_read = try in.pread(buf[0..adjusted_count], in_offset);
-        if (amt_read == 0) return @as(usize, 0);
-        return out.pwrite(buf[0..amt_read], out_offset);
+        return os.copy_file_range(in.handle, in_offset, out.handle, out_offset, len, 0);
     }
 
     /// Returns the number of bytes copied. If the number read is smaller than `buffer.len`, it
diff --git a/lib/std/fs/test.zig b/lib/std/fs/test.zig
index c9f1711967..26d8632c37 100644
--- a/lib/std/fs/test.zig
+++ b/lib/std/fs/test.zig
@@ -328,6 +328,32 @@ test "sendfile" {
     testing.expect(mem.eql(u8, written_buf[0..amt], "header1\nsecond header\nine1\nsecontrailer1\nsecond trailer\n"));
 }
 
+test "copyRangeAll" {
+    var tmp = tmpDir(.{});
+    defer tmp.cleanup();
+
+    try tmp.dir.makePath("os_test_tmp");
+    defer tmp.dir.deleteTree("os_test_tmp") catch {};
+
+    var dir = try tmp.dir.openDir("os_test_tmp", .{});
+    defer dir.close();
+
+    var src_file = try dir.createFile("file1.txt", .{ .read = true });
+    defer src_file.close();
+
+    const data = "u6wj+JmdF3qHsFPE BUlH2g4gJCmEz0PP";
+    try src_file.writeAll(data);
+
+    var dest_file = try dir.createFile("file2.txt", .{ .read = true });
+    defer dest_file.close();
+
+    var written_buf: [100]u8 = undefined;
+    _ = try src_file.copyRangeAll(0, dest_file, 0, data.len);
+
+    const amt = try dest_file.preadAll(&written_buf, 0);
+    testing.expect(mem.eql(u8, written_buf[0..amt], data));
+}
+
 test "fs.copyFile" {
     const data = "u6wj+JmdF3qHsFPE BUlH2g4gJCmEz0PP";
     const src_file = "tmp_test_copy_file.txt";