From ded3132b445475d37f9c43daa0b149c557eedbf5 Mon Sep 17 00:00:00 2001
From: Ivan Enderlin <ivan@mnt.io>
Date: Tue, 6 Oct 2020 11:09:35 +0200
Subject: [PATCH] feat(c-api) Implement `wat2wasm`.

---
 Makefile                        | 12 ++++++------
 lib/c-api/Cargo.toml            |  2 ++
 lib/c-api/build.rs              |  1 +
 lib/c-api/src/wasm_c_api/mod.rs |  2 ++
 lib/c-api/src/wasm_c_api/wat.rs | 30 ++++++++++++++++++++++++++++++
 lib/c-api/wasmer_wasm.h         |  8 ++++++++
 6 files changed, 49 insertions(+), 6 deletions(-)
 create mode 100644 lib/c-api/src/wasm_c_api/wat.rs

diff --git a/Makefile b/Makefile
index 3cb273b8abb..b4217370ae7 100644
--- a/Makefile
+++ b/Makefile
@@ -76,15 +76,15 @@ build-capi: build-capi-cranelift
 
 build-capi-singlepass:
 	cargo build --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,singlepass,wasi
+		--no-default-features --features wat,jit,singlepass,wasi
 
 build-capi-cranelift:
 	cargo build --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,cranelift,wasi
+		--no-default-features --features wat,jit,cranelift,wasi
 
 build-capi-llvm:
 	cargo build --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,llvm,wasi
+		--no-default-features --features wat,jit,llvm,wasi
 
 
 ###########
@@ -112,15 +112,15 @@ test-packages:
 
 test-capi-singlepass: build-capi-singlepass
 	cargo test --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,singlepass,wasi -- --nocapture
+		--no-default-features --features wat,jit,singlepass,wasi -- --nocapture
 
 test-capi-cranelift: build-capi-cranelift
 	cargo test --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,cranelift,wasi -- --nocapture
+		--no-default-features --features wat,jit,cranelift,wasi -- --nocapture
 
 test-capi-llvm: build-capi-llvm
 	cargo test --manifest-path lib/c-api/Cargo.toml --release \
-		--no-default-features --features jit,llvm,wasi -- --nocapture
+		--no-default-features --features wat,jit,llvm,wasi -- --nocapture
 
 test-capi: test-capi-singlepass test-capi-cranelift test-capi-llvm
 
diff --git a/lib/c-api/Cargo.toml b/lib/c-api/Cargo.toml
index 4bc32e47fdb..d33425c466e 100644
--- a/lib/c-api/Cargo.toml
+++ b/lib/c-api/Cargo.toml
@@ -40,9 +40,11 @@ paste = "0.1"
 
 [features]
 default = [
+    "wat",
     "cranelift",
     "wasi",
 ]
+wat = ["wasmer/wat"]
 wasi = ["wasmer-wasi", "typetag", "serde"]
 engine = []
 jit = [
diff --git a/lib/c-api/build.rs b/lib/c-api/build.rs
index 683c62f85c6..3f7c96ef8be 100644
--- a/lib/c-api/build.rs
+++ b/lib/c-api/build.rs
@@ -374,4 +374,5 @@ fn exclude_items_from_wasm_c_api(builder: Builder) -> Builder {
         .exclude_item("wasi_get_start_function")
         .exclude_item("wasi_get_wasi_version")
         .exclude_item("wasi_version_t")
+        .exclude_item("wat2wasm")
 }
diff --git a/lib/c-api/src/wasm_c_api/mod.rs b/lib/c-api/src/wasm_c_api/mod.rs
index 9d9d26485d5..de528d8bce8 100644
--- a/lib/c-api/src/wasm_c_api/mod.rs
+++ b/lib/c-api/src/wasm_c_api/mod.rs
@@ -29,3 +29,5 @@ pub mod value;
 
 #[cfg(feature = "wasi")]
 pub mod wasi;
+
+pub mod wat;
diff --git a/lib/c-api/src/wasm_c_api/wat.rs b/lib/c-api/src/wasm_c_api/wat.rs
new file mode 100644
index 00000000000..d093cd650ed
--- /dev/null
+++ b/lib/c-api/src/wasm_c_api/wat.rs
@@ -0,0 +1,30 @@
+use super::types::wasm_byte_vec_t;
+
+/// Parses in-memory bytes as either the WAT format, or a binary Wasm
+/// module. This is wasmer-specific.
+///
+/// In case of failure, `wat2wasm` returns `NULL`.
+#[cfg(feature = "wat")]
+#[no_mangle]
+pub unsafe extern "C" fn wat2wasm(wat: &wasm_byte_vec_t) -> Option<Box<wasm_byte_vec_t>> {
+    let wat: &[u8] = wat.into_slice()?;
+
+    let result = match wasmer::wat2wasm(wat) {
+        Ok(result) => result,
+        Err(error) => {
+            crate::error::update_last_error(error);
+
+            return None;
+        }
+    };
+
+    let mut result: Vec<u8> = result.into_owned();
+    result.shrink_to_fit();
+
+    let wasm = wasm_byte_vec_t {
+        size: result.len(),
+        data: result.as_mut_ptr(),
+    };
+
+    Some(Box::new(wasm))
+}
diff --git a/lib/c-api/wasmer_wasm.h b/lib/c-api/wasmer_wasm.h
index 4201bdd54ac..8e44602c9d8 100644
--- a/lib/c-api/wasmer_wasm.h
+++ b/lib/c-api/wasmer_wasm.h
@@ -177,4 +177,12 @@ int wasmer_last_error_length(void);
  */
 int wasmer_last_error_message(char *buffer, int length);
 
+/**
+ * Parses in-memory bytes as either the WAT format, or a binary Wasm
+ * module. This is wasmer-specific.
+ *
+ * In case of failure, `wat2wasm` returns `NULL`.
+ */
+wasm_byte_vec_t *wat2wasm(const wasm_byte_vec_t *wat);
+
 #endif /* WASMER_WASM_H */