From 97f10117486b34a96ccc8332c12dc662815e598c Mon Sep 17 00:00:00 2001
From: Alekos Filini <alekos.filini@gmail.com>
Date: Tue, 8 Feb 2022 17:01:03 +0100
Subject: [PATCH] Add a binary to generate bindings

---
 Cargo.toml          |  9 ++++++-
 build.rs            | 46 +-----------------------------------
 src/bin/generate.rs | 57 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+), 46 deletions(-)
 create mode 100644 src/bin/generate.rs

diff --git a/Cargo.toml b/Cargo.toml
index 6724e28..ba09fd3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,13 @@ uniffi = { version = "0.16.0", features = ["builtin-bindgen"] }
 thiserror = "1.0"
 anyhow = "=1.0.45" # remove after upgrading to next version of uniffi
 
+uniffi_bindgen = { version = "0.16.0", optional = true }
+
 [build-dependencies]
 uniffi_build = { version = "0.16.0", features = ["builtin-bindgen"] }
-uniffi_bindgen = { version = "0.16.0" }
+
+[features]
+generate-python = ["uniffi_bindgen"]
+
+[[bin]]
+name = "generate"
diff --git a/build.rs b/build.rs
index d72ea90..153077f 100644
--- a/build.rs
+++ b/build.rs
@@ -1,47 +1,3 @@
-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");
+    uniffi_build::generate_scaffolding("src/bdk.udl").unwrap();
 }
diff --git a/src/bin/generate.rs b/src/bin/generate.rs
new file mode 100644
index 0000000..d33a4b8
--- /dev/null
+++ b/src/bin/generate.rs
@@ -0,0 +1,57 @@
+use std::env;
+use std::fs;
+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 generate_python() -> Result<(), Box<dyn std::error::Error>> {
+    let out_path = env::var("GENERATE_PYTHON_BINDINGS_OUT")
+        .map_err(|_| String::from("`GENERATE_PYTHON_BINDINGS_OUT` env variable missing"))?;
+    uniffi_bindgen::generate_bindings(&format!("{}/{}", env!("CARGO_MANIFEST_DIR"), BDK_UDL), None, vec!["python"], Some(&out_path), false)?;
+
+    if let Some(name) = env::var("GENERATE_PYTHON_BINDINGS_FIXUP_LIB_PATH").ok() {
+        fixup_python_lib_path(&out_path, &name)?;
+    }
+
+    Ok(())
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    generate_python()
+}