From 2f6226518bd5085896a0f27cfd3ea396367ecd50 Mon Sep 17 00:00:00 2001 From: Andy Russell Date: Fri, 16 Nov 2018 16:22:06 -0500 Subject: use top level `fs` functions where appropriate This commit replaces many usages of `File::open` and reading or writing with `fs::read_to_string`, `fs::read` and `fs::write`. This reduces code complexity, and will improve performance for most reads, since the functions allocate the buffer to be the size of the file. I believe that this commit will not impact behavior in any way, so some matches will check the error kind in case the file was not valid UTF-8. Some of these cases may not actually care about the error. --- src/librustc_codegen_utils/codegen_backend.rs | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) (limited to 'src/librustc_codegen_utils') diff --git a/src/librustc_codegen_utils/codegen_backend.rs b/src/librustc_codegen_utils/codegen_backend.rs index b328873800e..74718460f56 100644 --- a/src/librustc_codegen_utils/codegen_backend.rs +++ b/src/librustc_codegen_utils/codegen_backend.rs @@ -22,8 +22,8 @@ #![feature(box_syntax)] use std::any::Any; -use std::io::{self, Write}; -use std::fs::File; +use std::io::Write; +use std::fs; use std::path::Path; use std::sync::{mpsc, Arc}; @@ -81,11 +81,7 @@ pub struct NoLlvmMetadataLoader; impl MetadataLoader for NoLlvmMetadataLoader { fn get_rlib_metadata(&self, _: &Target, filename: &Path) -> Result { - let mut file = File::open(filename) - .map_err(|e| format!("metadata file open err: {:?}", e))?; - - let mut buf = Vec::new(); - io::copy(&mut file, &mut buf).unwrap(); + let buf = fs::read(filename).map_err(|e| format!("metadata file open err: {:?}", e))?; let buf: OwningRef, [u8]> = OwningRef::new(buf); Ok(rustc_erase_owner!(buf.map_owner_box())) } @@ -209,8 +205,7 @@ impl CodegenBackend for MetadataOnlyCodegenBackend { } else { &ongoing_codegen.metadata.raw_data }; - let mut file = File::create(&output_name).unwrap(); - file.write_all(metadata).unwrap(); + fs::write(&output_name, metadata).unwrap(); } sess.abort_if_errors(); -- cgit 1.4.1-3-g733a5