From: Matt Corallo <git@bluematt.me>
Date: Tue, 4 Jan 2022 20:30:55 +0000 (+0000)
Subject: Support no_std on the generated crate
X-Git-Tag: v0.0.104.1^2~2
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=3fef735ad0382272f55cce06aefa489bcfaa2eb9;p=ldk-c-bindings

Support no_std on the generated crate
---

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 64bc90c..4a42cc3 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,7 +25,7 @@ jobs:
         run: |
           # Note that the version tags aren't checked into git
           touch src/version.rs
-          RUSTFLAGS="--cfg=c_bindings" cargo check
+          RUSTFLAGS="--cfg=c_bindings" cargo check --features std
       - name: Install cbindgen
         run: cargo install --force cbindgen
       - name: Checkout Rust-Lightning git
diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index da1ca4f..c6a74f6 100644
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -33,7 +33,15 @@ mod blocks;
 use types::*;
 use blocks::*;
 
-const DEFAULT_IMPORTS: &'static str = "\nuse std::str::FromStr;\nuse std::ffi::c_void;\nuse core::convert::Infallible;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n";
+const DEFAULT_IMPORTS: &'static str = "
+use alloc::str::FromStr;
+use core::ffi::c_void;
+use core::convert::Infallible;
+use bitcoin::hashes::Hash;
+use crate::c_types::*;
+#[cfg(feature=\"no-std\")]
+use alloc::{vec::Vec, boxed::Box};
+";
 
 // *************************************
 // *** Manually-expanded conversions ***
@@ -1726,6 +1734,12 @@ fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>
 			writeln!(out, "#![allow(unused_braces)]").unwrap();
 			// TODO: We need to map deny(missing_docs) in the source crate(s)
 			//writeln!(out, "#![deny(missing_docs)]").unwrap();
+
+			writeln!(out, "#![cfg_attr(not(feature = \"std\"), no_std)]").unwrap();
+			writeln!(out, "#[cfg(not(any(feature = \"std\", feature = \"no-std\")))]").unwrap();
+			writeln!(out, "compile_error!(\"at least one of the `std` or `no-std` features must be enabled\");").unwrap();
+			writeln!(out, "extern crate alloc;").unwrap();
+
 			writeln!(out, "pub mod version;").unwrap();
 			writeln!(out, "pub mod c_types;").unwrap();
 			writeln!(out, "pub mod bitcoin;").unwrap();
@@ -1972,6 +1986,7 @@ fn main() {
 
 	let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
 		.open(&args[2]).expect("Unable to open new header file");
+	writeln!(&mut derived_templates, "{}", DEFAULT_IMPORTS).unwrap();
 	let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
 		.open(&args[3]).expect("Unable to open new header file");
 	let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
diff --git a/lightning-c-bindings/src/c_types/mod.rs b/lightning-c-bindings/src/c_types/mod.rs
index 9e928a6..0bd976b 100644
--- a/lightning-c-bindings/src/c_types/mod.rs
+++ b/lightning-c-bindings/src/c_types/mod.rs
@@ -20,6 +20,8 @@ use core::ffi::c_void;
 pub(crate) use std::io::{self, Cursor, Read};
 #[cfg(feature = "no-std")]
 pub(crate) use core2::io::{self, Cursor, Read};
+#[cfg(feature = "no-std")]
+use alloc::{boxed::Box, vec::Vec, string::String};
 
 #[repr(C)]
 /// A dummy struct of which an instance must never exist.
@@ -192,6 +194,7 @@ pub enum IOError {
 	Other,
 	UnexpectedEof,
 }
+#[cfg(feature = "std")]
 impl IOError {
 	pub(crate) fn from_rust(err: std::io::Error) -> Self {
 		match err.kind() {
@@ -576,6 +579,9 @@ impl<T> TakePointer<*mut T> for *mut T {
 
 
 pub(crate) mod ObjOps {
+	#[cfg(feature = "no-std")]
+	use alloc::boxed::Box;
+
 	#[inline]
 	#[must_use = "returns new dangling pointer"]
 	pub(crate) fn heap_alloc<T>(obj: T) -> *mut T {