feat: add MOZJS_MIRROR and MOZJS_CREATE_MIRROR env variables

.github/workflows/rust.yml

@@ -15,6 +15,7 @@ env:
   RUST_BACKTRACE: 1
   SHELL: /bin/bash
   CARGO_INCREMENTAL: 0
+  MOZJS_CREATE_MIRROR: 1
 
 jobs:
   mac:

mozjs-sys/Cargo.toml

@@ -38,3 +38,5 @@ libz-sys = "1.1"
 bindgen.workspace = true
 cc.workspace = true
 walkdir = "2"
+flate2 = "1"
+tar = "0.4"

mozjs-sys/build.rs

@@ -3,12 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use bindgen::Formatter;
+use flate2::read::GzDecoder;
+use flate2::write::GzEncoder;
+use flate2::Compression;
 use std::env;
 use std::ffi::{OsStr, OsString};
-use std::fs;
+use std::fs::{self, File};
 use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::str;
+use tar::Archive;
 use walkdir::WalkDir;
 
 const ENV_VARS: &'static [&'static str] = &[
@@ -52,12 +56,21 @@ fn main() {
     // Used by mozjs downstream, don't remove.
     println!("cargo:outdir={}", build_dir.display());
 
-    fs::create_dir_all(&build_dir).expect("could not create build dir");
-
-    build_spidermonkey(&build_dir);
-    build_jsapi(&build_dir);
-    build_jsapi_bindings(&build_dir);
-    jsglue::build(&build_dir);
+    let mirror = env::var_os("MOZJS_MIRROR");
+    if mirror.is_some() {
+        download_static_lib_binaries(&PathBuf::from(mirror.unwrap()), &build_dir);
+    } else {
+        fs::create_dir_all(&build_dir).expect("could not create build dir");
+        build_spidermonkey(&build_dir);
+        build_jsapi(&build_dir);
+        build_jsapi_bindings(&build_dir);
+        jsglue::build(&build_dir);
+
+        // If this env variable is set, create the compressed tarball of spidermonkey.
+        if env::var_os("MOZJS_CREATE_MIRROR").is_some() {
+            compress_static_lib(&build_dir).expect("Failed to compress static lib binaries.");
+        }
+    }
 
     if env::var_os("MOZJS_FORCE_RERUN").is_none() {
         for var in ENV_VARS {
@@ -615,6 +628,7 @@ mod jsglue {
             false
         };
 
+        build.out_dir(outdir);
         build.compile("jsglue");
         println!("cargo:rerun-if-changed=src/jsglue.cpp");
         let mut builder = bindgen::Builder::default()
@@ -702,3 +716,82 @@ mod jsglue {
         ("root::JS", "pub(crate) use crate::jsapi::JS::*;"),
     ];
 }
+
+/// Compress spidermonkey build into a tarball with necessary static binaries and bindgen wrappers.
+fn compress_static_lib(build_dir: &Path) -> Result<(), std::io::Error> {
+    // // Strip symbols from the static binary since it could bump up to 1.6GB on Linux.
+    // // TODO: Maybe we could separate symbols for thos who still want the debug ability.
+    // // https://github.com/GabrielMajeri/separate-symbols
+    // let status = Command::new("strip")
+    //     .arg(build_dir.join("js/src/build/libjs_static.a"))
+    //     .status()
+    //     .unwrap();
+    // assert!(status.success());
+
+    let tar_gz = File::create("libjs.tar.gz")?;
+    let enc = GzEncoder::new(tar_gz, Compression::default());
+    let mut tar = tar::Builder::new(enc);
+    // This is the static library of spidermonkey.
+    tar.append_file(
+        "libjs_static.a",
+        &mut File::open(build_dir.join("js/src/build/libjs_static.a")).unwrap(),
+    )?;
+    // The bindgen binaries and generated rust files for mozjs.
+    tar.append_file(
+        "libjsapi.a",
+        &mut File::open(build_dir.join("libjsapi.a")).unwrap(),
+    )?;
+    tar.append_file(
+        "libjsglue.a",
+        &mut File::open(build_dir.join("libjsglue.a")).unwrap(),
+    )?;
+    tar.append_file(
+        "jsapi.rs",
+        &mut File::open(build_dir.join("jsapi.rs")).unwrap(),
+    )?;
+    tar.append_file(
+        "gluebindings.rs",
+        &mut File::open(build_dir.join("gluebindings.rs")).unwrap(),
+    )?;
+    Ok(())
+}
+
+/// Decompress the mirror of spidermonkey build to to build directory.
+fn decompress_static_lib(mirror: &Path, build_dir: &Path) -> Result<(), std::io::Error> {
+    let tar_gz = File::open(mirror)?;
+    let tar = GzDecoder::new(tar_gz);
+    let mut archive = Archive::new(tar);
+    archive.unpack(build_dir)?;
+    Ok(())
+}
+
+/// Download static library tarball instead of building it from source.
+fn download_static_lib_binaries(mirror: &Path, build_dir: &Path) {
+    // Only download the files if build directory doesn't exist.
+    if !build_dir.exists() {
+        // TODO download from https
+        decompress_static_lib(mirror, build_dir).expect("Failed to decompress statuc libs");
+    }
+
+    // Link static lib binaries
+    let target = env::var("TARGET").unwrap();
+    println!("cargo:rustc-link-search=native={}", build_dir.display());
+    println!("cargo:rustc-link-lib=static=js_static"); // Must come before c++
+    if target.contains("windows") {
+        println!("cargo:rustc-link-search=native={}", build_dir.display());
+        println!("cargo:rustc-link-lib=winmm");
+        println!("cargo:rustc-link-lib=psapi");
+        println!("cargo:rustc-link-lib=user32");
+        println!("cargo:rustc-link-lib=Dbghelp");
+        if target.contains("gnu") {
+            println!("cargo:rustc-link-lib=stdc++");
+        }
+    } else if target.contains("apple") || target.contains("freebsd") {
+        println!("cargo:rustc-link-lib=c++");
+    } else {
+        println!("cargo:rustc-link-lib=stdc++");
+    }
+    // Link bindgen binaries
+    println!("cargo:rustc-link-lib=static=jsapi");
+    println!("cargo:rustc-link-lib=static=jsglue");
+}