feat: add WebAssembly support for C/C++ FFI and CI validation (#29)

* feat: add WebAssembly support for C/C++ FFI and CI validation

* feat: update roadmap and documentation for WASM & no_std support in versions 1.1.0 & 1.1.1

Author: AteebNoOne

.github/workflows/wasm-build.yml

@@ -33,6 +33,9 @@ jobs:
           - name: wasm32-unknown-unknown-example
             target: wasm32-unknown-unknown
             command: cargo build -p tinyxml2 --target wasm32-unknown-unknown --example wasm_parse
+          - name: wasm32-unknown-unknown-capi
+            target: wasm32-unknown-unknown
+            command: cargo build -p tinyxml2-capi --target wasm32-unknown-unknown --release
           - name: wasm32-wasip1
             target: wasm32-wasip1
             command: cargo build -p tinyxml2 --target wasm32-wasip1
@@ -42,6 +45,9 @@ jobs:
           - name: wasm32-wasip1-example
             target: wasm32-wasip1
             command: cargo build -p tinyxml2 --target wasm32-wasip1 --example wasm_parse
+          - name: wasm32-wasip1-capi
+            target: wasm32-wasip1
+            command: cargo build -p tinyxml2-capi --target wasm32-wasip1 --release
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4

CHANGELOG.md

@@ -2,8 +2,19 @@
 
 All notable changes to this project will be documented in this file.
 
-The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
-and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+## [1.1.1] - 2026-07-14
+
+### Added
+- **WebAssembly Support for C/C++ FFI**: Enabled compilation of the `tinyxml2-capi` FFI bindings crate for `wasm32-unknown-unknown` and `wasm32-wasip1` targets. C and C++ projects compiled to WebAssembly (via Emscripten or WASI SDK) can now link with the static library (`libtinyxml2_capi.a`) as a drop-in replacement.
+- **CI Validation for C/C++ WASM**: Added automated GitHub Actions check to compile `tinyxml2-capi` for WASM targets.
+- **WASM FFI Integration Guide**: Added detailed compilation and linking instructions for Emscripten (`emcc`) and WASI SDK (`clang`) under `docs/architecture/wasm.md`.
+
+## [1.1.0] - 2026-07-01
+
+### Added
+- **`no_std` Support**: Added `no_std` support with `alloc` allocator feature-gated for resource-constrained environments.
+- **Rust WASM Support**: Verified compilation and execution of `tinyxml2` core library under `wasm32-unknown-unknown` and `wasm32-wasip1`.
+- **Abstract I/O**: File operations and stream writers are now feature-gated under the `std` feature.
 
 ## [1.0.0] - 2026-07-01
 

Cargo.lock

@@ -9,7 +9,7 @@ members = [
 ]
 
 [workspace.package]
-version = "1.1.0"
+version = "1.1.1"
 edition = "2024"
 rust-version = "1.85.0"
 license = "MIT"

Cargo.toml

@@ -309,15 +309,18 @@ parse_document()
 
 ---
 
-## Phase 9: WASM & `no_std` Support (Target: Version 1.1.0) ✅ **COMPLETED**
+## Phase 9: WASM & `no_std` Support (Target: Versions 1.1.0 & 1.1.1) ✅ **COMPLETED**
 
 Enable tinyxml2-rs to run in resource-constrained embedded environments and web browsers.
 
-### Key Deliverables
+### Key Deliverables (v1.1.0)
 - [x] **no_std compatibility** — Feature-gate standard library dependencies and use the `alloc` crate for all dynamic memory allocations (`Vec`, `String`, `Box`). Target: `#![no_std]` with `extern crate alloc`.
 - [x] **WASM target support** — Validate the core crate on `wasm32-unknown-unknown` and `wasm32-wasip1`. JavaScript bindings are intentionally left to the host application boundary; see `docs/architecture/wasm.md`.
 - [x] **Abstract I/O** — Gate file/stream writers behind the `std` feature and keep the core parser, DOM, and string serialization available without `std::io::Write`.
 
+### Key Deliverables (v1.1.1)
+- [x] **C/C++ FFI WASM Support** — Support compiling and linking the FFI bindings (`tinyxml2-capi`) on `wasm32-unknown-unknown` and `wasm32-wasip1` targets for C/C++ WebAssembly integration.
+
 ---
 
 ## Phase 10: XPath & Serde Integration (Target: Version 1.2.0) 🔲 **PLANNED**

ROADMAP.md

@@ -88,18 +88,74 @@ feature. Validate no_std support with `--lib`, or from a consumer crate that
 supplies the allocator, panic strategy, and host boundary required by that
 environment.
 
+## C and C++ WebAssembly Support
+
+The C FFI compatibility layer (`tinyxml2-capi`) compiles to WebAssembly targets out of the box. C and C++ projects compiled to WebAssembly (via Emscripten or WASI SDK) can link against this compiled Rust artifact as a drop-in replacement.
+
+> [!NOTE]
+> The project's CI validates compiling the Rust artifacts (`libtinyxml2_capi.a` and `tinyxml2_capi.wasm`) for WASM targets. Compiling and linking the final C/C++ application remains the responsibility of the consumer's C toolchain (e.g. Emscripten or WASI SDK).
+
+When compiled to `wasm32-unknown-unknown` or `wasm32-wasip1`, it generates:
+- A WebAssembly binary (`tinyxml2_capi.wasm`)
+- A static library (`libtinyxml2_capi.a`)
+
+### Compiling the C FFI for WebAssembly
+
+To compile the C FFI bindings library for WebAssembly:
+
+```bash
+# Target the browser / JavaScript environment (e.g. for Emscripten)
+cargo build -p tinyxml2-capi --target wasm32-unknown-unknown --release
+
+# Target WASI environments (e.g. for Wasmtime, Wasmer)
+cargo build -p tinyxml2-capi --target wasm32-wasip1 --release
+```
+
+The resulting library `libtinyxml2_capi.a` will be located under `target/wasm32-unknown-unknown/release/` or `target/wasm32-wasip1/release/`.
+
+### Linking in C/C++ WebAssembly Projects
+
+#### 1. Browser/Emscripten Toolchain (`emcc`)
+To compile a C/C++ file with Emscripten and link the Rust WASM static library:
+
+```bash
+emcc -Icrates/tinyxml2-capi/include -O3 \
+  crates/tinyxml2-capi/examples/basic.c \
+  target/wasm32-unknown-unknown/release/libtinyxml2_capi.a \
+  -o basic.js \
+  -s WASM=1 \
+  -s ALLOW_MEMORY_GROWTH=1
+```
+
+#### 2. WASI SDK Toolchain (`clang`)
+To compile for a standalone WASI runtime (e.g., Wasmtime) using the WASI SDK:
+
+```bash
+/path/to/wasi-sdk/bin/clang -Icrates/tinyxml2-capi/include -O3 \
+  --sysroot=/path/to/wasi-sysroot \
+  crates/tinyxml2-capi/examples/basic.c \
+  target/wasm32-wasip1/release/libtinyxml2_capi.a \
+  -o basic.wasm
+```
+
+### ABI and Memory Considerations
+- **Shared Memory**: Since Rust and C/C++ compile into a single WebAssembly module when linked statically, they share the same linear memory and allocator (supplied by the C runtime or Rust's target).
+- **String Lifetimes**: Pointers returned by `tx_document_to_string`, `tx_element_name`, or other getters returning `*const c_char` point to UTF-8 C-strings borrowed from the `TxDocument`/`TxPrinter`-owned `CString` caches. Callers **must not free** these pointers. They become invalid as soon as the document is modified (mutated) or when the owning document/printer wrapper is freed.
+
 ## Validation
 
-Use these commands when changing parser, DOM, or serialization code:
+Use these commands when changing parser, DOM, serialization, or FFI code:
 
 ```bash
 cargo check -p tinyxml2
 cargo check -p tinyxml2 --no-default-features --lib
 cargo check -p tinyxml2 --no-default-features --target wasm32-unknown-unknown --lib
 cargo check -p tinyxml2 --target wasm32-wasip1 --lib
 cargo build -p tinyxml2 --target wasm32-unknown-unknown --example wasm_parse
+cargo build -p tinyxml2-capi --target wasm32-unknown-unknown --release
+cargo build -p tinyxml2-capi --target wasm32-wasip1 --release
 cargo test -p tinyxml2 --all-targets
+cargo test -p tinyxml2-capi
 ```
 
-Workspace crates that bind to native C/C++ code, such as `tinyxml2-capi`,
-`tinyxml2-bench`, and `tinyxml2-cpp-helper`, remain native-only.
+Workspace crates that bind to native C/C++ code, such as `tinyxml2-bench` and `tinyxml2-cpp-helper`, remain native-only.