Add support for @file args

CHANGELOG.md

@@ -7,12 +7,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+- [#96] Add support for @file args
 - [#94] Refactor tests
 - [#93] Remove TryInto import (in prelude since 2021 edition)
 - [#92] Recommend `target.'cfg(..)'.linker` for recent Cargo versions
 - [#90] Configure release-plz
 - [#88] Setup release-plz
 
+[#96]: https://github.com/knurling-rs/flip-link/pull/96
 [#94]: https://github.com/knurling-rs/flip-link/pull/94
 [#93]: https://github.com/knurling-rs/flip-link/pull/93
 [#92]: https://github.com/knurling-rs/flip-link/pull/92

src/argument_parser.rs

@@ -1,4 +1,9 @@
-use std::{borrow::Cow, path::PathBuf};
+use std::{
+    borrow::Cow,
+    fs::File,
+    io::{BufRead, BufReader},
+    path::PathBuf,
+};
 
 /// Get `output_path`, specified by `-o`
 pub fn get_output_path(args: &[String]) -> crate::Result<&String> {
@@ -22,3 +27,36 @@ pub fn get_search_targets(args: &[String]) -> Vec<Cow<str>> {
         .filter_map(|arg| arg.strip_prefix("-T").map(Cow::Borrowed))
         .collect()
 }
+
+/// Exapnds @file arguments into the file's contents
+pub fn expand_files(args: &[String]) -> Vec<String> {
+    let mut expanded = Vec::with_capacity(args.len());
+
+    for arg in args {
+        if let Some(arg) = arg.strip_prefix('@') {
+            // The normal linker was able to open the file, so this *should* never panic
+            let file = File::open(arg).unwrap_or_else(|e| {
+                panic!("Unable to open {arg}, this should never happen and should be reported: {e}")
+            });
+            let reader = BufReader::new(file);
+            for line in reader.lines() {
+                // Same as above, normal linker succeeded so we should too
+                let line = line.unwrap_or_else(|e| {
+                    panic!(
+                        "Invalid file {arg}, this should never happen and should be reported: {e}"
+                    )
+                });
+                // Remove quotes if they exist
+                if line.starts_with('"') && line.ends_with('"') {
+                    expanded.push(line[1..line.len() - 1].to_owned());
+                } else {
+                    expanded.push(line.to_owned());
+                }
+            }
+        } else {
+            expanded.push(arg.clone());
+        }
+    }
+
+    expanded
+}

src/main.rs

@@ -27,22 +27,23 @@ fn notmain() -> Result<i32> {
     env_logger::init();
 
     // NOTE `skip` the name/path of the binary (first argument)
-    let args = env::args().skip(1).collect::<Vec<_>>();
+    let raw_args = env::args().skip(1).collect::<Vec<_>>();
 
     {
-        let exit_status = linking::link_normally(&args)?;
+        let exit_status = linking::link_normally(&raw_args)?;
         if !exit_status.success() {
             eprintln!(
                 "\nflip-link: the native linker failed to link the program normally; \
-                 please check your project configuration and linker scripts"
+                please check your project configuration and linker scripts"
             );
             return Ok(exit_status.code().unwrap_or(EXIT_CODE_FAILURE));
         }
         // if linking succeeds then linker scripts are well-formed; we'll rely on that in the parser
     }
 
+    let expanded_args = argument_parser::expand_files(&raw_args);
     let current_dir = env::current_dir()?;
-    let linker_scripts = get_linker_scripts(&args, &current_dir)?;
+    let linker_scripts = get_linker_scripts(&expanded_args, &current_dir)?;
 
     // here we assume that we'll end with the same linker script as LLD
     // I'm unsure about how LLD picks a linker script when there are multiple candidates in the
@@ -59,7 +60,7 @@ fn notmain() -> Result<i32> {
     let (ram_linker_script, ram_entry) =
         ram_path_entry.ok_or("MEMORY.RAM not found after scanning linker scripts")?;
 
-    let output_path = argument_parser::get_output_path(&args)?;
+    let output_path = argument_parser::get_output_path(&expanded_args)?;
     let elf = fs::read(output_path)?;
     let object = object::File::parse(elf.as_slice())?;
 
@@ -99,7 +100,7 @@ fn notmain() -> Result<i32> {
         }
         new_linker_script.flush()?;
 
-        let exit_status = linking::link_modified(&args, &current_dir, tempdir, new_origin)?;
+        let exit_status = linking::link_modified(&raw_args, &current_dir, tempdir, new_origin)?;
         Ok(exit_status)
     })?;