From 5c6cdf5ab6399604695c94031e32087cfe3367ae Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 12 Feb 2024 20:55:14 +0100
Subject: [PATCH] Add `info` command to help get some information

---
 build_system/src/config.rs | 35 +++++++++++++++--------------------
 build_system/src/info.rs   | 19 +++++++++++++++++++
 build_system/src/main.rs   |  5 +++++
 3 files changed, 39 insertions(+), 20 deletions(-)
 create mode 100644 build_system/src/info.rs

diff --git a/build_system/src/config.rs b/build_system/src/config.rs
index a206bab14a9a..48be515a1f0f 100644
--- a/build_system/src/config.rs
+++ b/build_system/src/config.rs
@@ -121,6 +121,9 @@ pub struct ConfigInfo {
     pub gcc_path: String,
     config_file: Option<String>,
     cg_gcc_path: Option<PathBuf>,
+    // Needed for the `info` command which doesn't want to actually download the lib if needed,
+    // just to set the `gcc_path` field to display it.
+    pub no_download: bool,
 }
 
 impl ConfigInfo {
@@ -204,7 +207,7 @@ impl ConfigInfo {
             return Err(format!(
                 "{}: invalid commit hash `{}`",
                 commit_hash_file.display(),
-                commit
+                commit,
             ));
         }
         let output_dir = output_dir.join(commit);
@@ -217,9 +220,17 @@ impl ConfigInfo {
                 )
             })?;
         }
+        let output_dir = output_dir.canonicalize().map_err(|err| {
+            format!(
+                "Failed to get absolute path of `{}`: {:?}",
+                output_dir.display(),
+                err
+            )
+        })?;
+
         let libgccjit_so_name = "libgccjit.so";
         let libgccjit_so = output_dir.join(libgccjit_so_name);
-        if !libgccjit_so.is_file() {
+        if !libgccjit_so.is_file() && !self.no_download {
             // Download time!
             let tempfile_name = "libgccjit.so.download";
             let tempfile = output_dir.join(tempfile_name);
@@ -283,28 +294,12 @@ impl ConfigInfo {
 
             println!("Downloaded libgccjit.so version {} successfully!", commit);
             create_symlink(
-                &libgccjit_so.canonicalize().map_err(|err| {
-                    format!(
-                        "Failed to get absolute path of `{}`: {:?}",
-                        libgccjit_so.display(),
-                        err,
-                    )
-                })?,
+                &libgccjit_so,
                 output_dir.join(&format!("{}.0", libgccjit_so_name)),
             )?;
         }
 
-        self.gcc_path = output_dir
-            .canonicalize()
-            .map_err(|err| {
-                format!(
-                    "Failed to get absolute path of `{}`: {:?}",
-                    output_dir.display(),
-                    err
-                )
-            })?
-            .display()
-            .to_string();
+        self.gcc_path = output_dir.display().to_string();
         println!("Using `{}` as path for libgccjit", self.gcc_path);
         Ok(())
     }
diff --git a/build_system/src/info.rs b/build_system/src/info.rs
new file mode 100644
index 000000000000..ea38791d38c9
--- /dev/null
+++ b/build_system/src/info.rs
@@ -0,0 +1,19 @@
+use crate::config::ConfigInfo;
+
+pub fn run() -> Result<(), String> {
+    let mut config = ConfigInfo::default();
+
+    // We skip binary name and the `info` command.
+    let mut args = std::env::args().skip(2);
+    while let Some(arg) = args.next() {
+        if arg == "--help" {
+            println!("Display the path where the libgccjit will be located");
+            return Ok(());
+        }
+        config.parse_argument(&arg, &mut args)?;
+    }
+    config.no_download = true;
+    config.setup_gcc_path()?;
+    println!("{}", config.gcc_path);
+    Ok(())
+}
diff --git a/build_system/src/main.rs b/build_system/src/main.rs
index 102c5486a75e..c6958f0c5124 100644
--- a/build_system/src/main.rs
+++ b/build_system/src/main.rs
@@ -5,6 +5,7 @@ mod build;
 mod cargo;
 mod clean;
 mod config;
+mod info;
 mod prepare;
 mod rustc_info;
 mod test;
@@ -29,6 +30,7 @@ Available commands for build_system:
     prepare  : Run prepare command
     build    : Run build command
     test     : Run test command
+    info:    : Run info command
     --help   : Show this message"
     );
 }
@@ -39,6 +41,7 @@ pub enum Command {
     Prepare,
     Build,
     Test,
+    Info,
 }
 
 fn main() {
@@ -52,6 +55,7 @@ fn main() {
         Some("prepare") => Command::Prepare,
         Some("build") => Command::Build,
         Some("test") => Command::Test,
+        Some("info") => Command::Info,
         Some("--help") => {
             usage();
             process::exit(0);
@@ -70,6 +74,7 @@ fn main() {
         Command::Prepare => prepare::run(),
         Command::Build => build::run(),
         Command::Test => test::run(),
+        Command::Info => info::run(),
     } {
         eprintln!("Command failed to run: {e}");
         process::exit(1);