From 167d83ca4521e7e604747142d2a2b79ecb3f7677 Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Fri, 14 May 2021 21:36:50 -0600
Subject: provide stdlib

---
 Cargo.toml |  2 ++
 build.rs   | 21 +++++++++++++++++++++
 src/lib.rs | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/Cargo.toml b/Cargo.toml
index 53943d1..d4f9960 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,9 @@ categories = ["external-ffi-bindings"]
 links = "tcl"
 
 [dependencies]
+flate2 = "1.0.20"
 libc = "0.2.94"
+tar = "0.4.33"
 
 [build-dependencies]
 bindgen = "0.58.1"
diff --git a/build.rs b/build.rs
index acbf264..8baa99f 100644
--- a/build.rs
+++ b/build.rs
@@ -199,6 +199,7 @@ fn main() {
     generate_bindings(target.as_str(), host.as_str(), include_paths.as_slice());
 
     link_tcl(target_os);
+    compress_stdlib(tcl_lib_path.join("tcl8.6"));
 
     println!("cargo:rerun-if-changed=build.rs");
 }
@@ -250,6 +251,26 @@ fn generate_bindings(target: &str, host: &str, headers_paths: &[String]) {
         .expect("Couldn't write bindings!");
 }
 
+fn compress_stdlib(stdlib_root: PathBuf) {
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let tcl_stdlib_archive_path = Path::new(&out_dir).join("stdlib.tar.gz");
+    let writer = flate2::write::GzEncoder::new(
+        fs::File::create(tcl_stdlib_archive_path).unwrap(),
+        flate2::Compression::best(),
+    );
+    let mut ar = tar::Builder::new(writer);
+
+    for child in stdlib_root.read_dir().unwrap() {
+        let child = child.unwrap();
+        if child.path().is_dir() {
+            ar.append_dir_all(child.file_name(), child.path()).unwrap();
+        } else {
+            ar.append_path_with_name(child.path(), child.file_name())
+                .unwrap();
+        }
+    }
+}
+
 fn get_os_from_triple(triple: &str) -> Option<&str> {
     triple.splitn(3, "-").nth(2)
 }
diff --git a/src/lib.rs b/src/lib.rs
index d403fbc..a1dfc93 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,38 @@
 
 include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
 
+mod stdlib {
+    use std::env::current_exe;
+    use std::io;
+    use std::path::{Path, PathBuf};
+
+    const STDLIB_DATA: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/stdlib.tar.gz"));
+
+    /// Guess where tcl will look for the standard library (from the directory containing the current executable, ../lib/tcl8.6/).
+    pub fn guess_expected_stdlib_target() -> PathBuf {
+        let exe = current_exe().unwrap();
+        let exe_parent = exe.parent().unwrap();
+        let exe_parent_parent = exe_parent.parent().unwrap();
+        let exe_parent_parent_lib = exe_parent_parent.join("lib");
+        let expected_stdlib_path = exe_parent_parent_lib.join("tcl8.6");
+        expected_stdlib_path
+    }
+
+    /// Extract the built-in standard library to the given path, ignoring if already exists.
+    pub fn extract_stdlib_to(target: impl AsRef<Path>) -> io::Result<()> {
+        let reader = flate2::read::GzDecoder::new(STDLIB_DATA);
+        let mut ar = tar::Archive::new(reader);
+        ar.set_overwrite(false);
+        let result = ar.unpack(target);
+        match result {
+            Err(e) if e.kind() == io::ErrorKind::AlreadyExists => Ok(()),
+            x => x,
+        }
+    }
+}
+
+pub use stdlib::*;
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -12,6 +44,7 @@ mod tests {
     #[test]
     fn two_plus_two() {
         unsafe {
+            extract_stdlib_to(guess_expected_stdlib_target()).unwrap();
             let interp = Tcl_CreateInterp();
             let init_status = Tcl_Init(interp);
             if init_status == TCL_ERROR as i32 {
-- 
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