Generate bindings for Python in build.rs

Cargo.toml

@@ -11,10 +11,11 @@ name = "bdkffi"
 
 [dependencies]
 bdk = { version = "0.14", features = ["all-keys", "use-esplora-ureq"] }
-uniffi_macros = "0.16.0"
-uniffi = "0.16.0"
+uniffi_macros = { version = "0.16.0", features = ["builtin-bindgen"] }
+uniffi = { version = "0.16.0", features = ["builtin-bindgen"] }
 thiserror = "1.0"
 anyhow = "=1.0.45" # remove after upgrading to next version of uniffi
 
 [build-dependencies]
-uniffi_build = "0.16.0"
+uniffi_build = { version = "0.16.0", features = ["builtin-bindgen"] }
+uniffi_bindgen = { version = "0.16.0" }

build.rs

@@ -1,3 +1,47 @@
-fn main() {
-    uniffi_build::generate_scaffolding("src/bdk.udl").unwrap();
+use std::fs;
+use std::env;
+use std::io::Write;
+use std::path::Path;
+
+const BDK_UDL: &str = "src/bdk.udl";
+
+fn fixup_python_lib_path<O: AsRef<Path>>(out_dir: O, lib_name: &str) -> Result<(), Box<dyn std::error::Error>> {
+    const LOAD_INDIRECT_DEF: &str = "def loadIndirect():";
+
+    let bindings_file = out_dir.as_ref().join("bdk.py");
+    let mut data = fs::read_to_string(&bindings_file)?;
+
+    let pos = data.find(LOAD_INDIRECT_DEF).expect(&format!("loadIndirect not found in `{}`", bindings_file.display()));
+    let range = pos..pos + LOAD_INDIRECT_DEF.len();
+
+    let replacement = format!(r#"
+def loadIndirect():
+    import glob
+    return getattr(ctypes.cdll, glob.glob(os.path.join(os.path.dirname(os.path.abspath(__file__)), '{}.*'))[0])
+
+def _loadIndirectOld():"#, lib_name);
+    data.replace_range(range, &replacement);
+
+    let mut file = fs::OpenOptions::new().write(true).truncate(true).open(&bindings_file)?;
+    file.write(data.as_bytes())?;
+
+    Ok(())
+}
+
+fn main() {
+    uniffi_build::generate_scaffolding(BDK_UDL).unwrap();
+
+    if let Some(lang) = env::var("GENERATE_BINDINGS_LANG").ok() {
+        let out_path = env::var("GENERATE_BINDINGS_OUT").expect("GENERATE_BINDINGS_OUT must be set when GENERATE_BINDINGS_LANG is");
+        uniffi_bindgen::generate_bindings(BDK_UDL, None, vec![&lang], Some(&out_path), false).unwrap();
+
+        match (lang.as_ref(), env::var("GENERATE_BINDINGS_FIXUP_LIB_PATH").ok()) {
+            ("python", Some(name)) => fixup_python_lib_path(&out_path, &name).unwrap(),
+            _ => {},
+        }
+    }
+
+    println!("cargo:rerun-if-changed=GENERATE_BINDINGS_LANG");
+    println!("cargo:rerun-if-changed=GENERATE_BINDINGS_OUT");
+    println!("cargo:rerun-if-changed=GENERATE_BINDINGS_FIXUP_LIB_PATH");
 }