From 95309db710873156f3650591dd033571ee07ffca Mon Sep 17 00:00:00 2001
From: leeeon233 <leeeon233@gmail.com>
Date: Sat, 28 Jan 2023 19:59:37 +0800
Subject: [PATCH] feat: impl C ffi

---
 crates/loro-ffi/.gitignore            |  2 ++
 crates/loro-ffi/build.rs              | 35 +++-----------------
 crates/loro-ffi/cbindgen.toml         |  6 +++-
 crates/loro-ffi/examples/cpp/loro.cpp | 14 ++++++++
 crates/loro-ffi/src/lib.rs            | 46 ++++++++++++++++++++++++++-
 5 files changed, 70 insertions(+), 33 deletions(-)
 create mode 100644 crates/loro-ffi/.gitignore
 create mode 100644 crates/loro-ffi/examples/cpp/loro.cpp

diff --git a/crates/loro-ffi/.gitignore b/crates/loro-ffi/.gitignore
new file mode 100644
index 00000000..611bb729
--- /dev/null
+++ b/crates/loro-ffi/.gitignore
@@ -0,0 +1,2 @@
+examples/cpp/loro
+examples/cpp/*.a
\ No newline at end of file
diff --git a/crates/loro-ffi/build.rs b/crates/loro-ffi/build.rs
index 03b51f64..d8460b5c 100644
--- a/crates/loro-ffi/build.rs
+++ b/crates/loro-ffi/build.rs
@@ -1,35 +1,8 @@
-extern crate cbindgen;
-
-use cbindgen::Config;
-use std::env;
-use std::path::PathBuf;
-
 fn main() {
-    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
-
-    let package_name = env::var("CARGO_PKG_NAME").unwrap();
-    let output_file = target_dir()
-        .join(format!("{}.hpp", package_name))
-        .display()
-        .to_string();
-
-    let config = Config {
-        namespace: Some(String::from("loro_ffi")),
-        ..Default::default()
-    };
-
+    let crate_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    let config = cbindgen::Config::from_file("cbindgen.toml")
+        .expect("Unable to find cbindgen.toml configuration file");
     cbindgen::generate_with_config(&crate_dir, config)
         .unwrap()
-        .write_to_file(&output_file);
-}
-
-/// Find the location of the `target/` directory. Note that this may be
-/// overridden by `cmake`, so we also need to check the `CARGO_TARGET_DIR`
-/// variable.
-fn target_dir() -> PathBuf {
-    if let Ok(target) = env::var("CARGO_TARGET_DIR") {
-        PathBuf::from(target)
-    } else {
-        PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("target")
-    }
+        .write_to_file("target/loro_ffi.h");
 }
diff --git a/crates/loro-ffi/cbindgen.toml b/crates/loro-ffi/cbindgen.toml
index 98188b59..39aae0e6 100644
--- a/crates/loro-ffi/cbindgen.toml
+++ b/crates/loro-ffi/cbindgen.toml
@@ -1,3 +1,7 @@
-include_guard = "libloro_ffi_h"
+header = """
+typedef struct LoroCore {} LoroCore;
+
+typedef struct Text {} Text;
+"""
 autogen_warning = "/* Warning, this file is autogenerated by cbindgen. Don't modify this manually. */"
 language = "C"
diff --git a/crates/loro-ffi/examples/cpp/loro.cpp b/crates/loro-ffi/examples/cpp/loro.cpp
new file mode 100644
index 00000000..6e2115b6
--- /dev/null
+++ b/crates/loro-ffi/examples/cpp/loro.cpp
@@ -0,0 +1,14 @@
+#include <stdio.h>
+extern "C" {
+    #include "../../target/loro_ffi.h"
+};
+
+int main(void) {
+  LoroCore* loro = loro_new();
+  Text* text = loro_get_text(loro, "text");
+  text_insert(text, loro, 0, "abc");
+  char* str = text_value(text);
+  printf("%s", str);
+  text_free(text);
+  loro_free(loro);
+}
diff --git a/crates/loro-ffi/src/lib.rs b/crates/loro-ffi/src/lib.rs
index b2b7c9a2..d1b37f9b 100644
--- a/crates/loro-ffi/src/lib.rs
+++ b/crates/loro-ffi/src/lib.rs
@@ -1,4 +1,9 @@
-use loro_core::LoroCore;
+use std::ffi::{c_char, c_uint, CStr, CString};
+
+pub type LoroCore = loro_core::LoroCore;
+pub type Text = loro_core::Text;
+pub type List = loro_core::List;
+pub type Map = loro_core::Map;
 
 /// create Loro with a random unique client id
 #[no_mangle]
@@ -13,3 +18,42 @@ pub unsafe extern "C" fn loro_free(loro: *mut LoroCore) {
         drop(Box::from_raw(loro));
     }
 }
+
+#[no_mangle]
+pub unsafe extern "C" fn loro_get_text(loro: *mut LoroCore, id: *const c_char) -> *mut Text {
+    assert!(!loro.is_null());
+    assert!(!id.is_null());
+    let id = CStr::from_ptr(id).to_str().unwrap();
+    let text = loro.as_mut().unwrap().get_text(id);
+    Box::into_raw(Box::new(text))
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn text_free(text: *mut Text) {
+    if !text.is_null() {
+        drop(Box::from_raw(text));
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn text_insert(
+    text: *mut Text,
+    ctx: *const LoroCore,
+    pos: *const c_uint,
+    value: *const c_char,
+) {
+    assert!(!text.is_null());
+    assert!(!ctx.is_null());
+    let text = text.as_mut().unwrap();
+    let ctx = ctx.as_ref().unwrap();
+    let value = CStr::from_ptr(value).to_str().unwrap();
+    text.insert(ctx, pos as usize, value).unwrap();
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn text_value(text: *mut Text) -> *mut c_char {
+    assert!(!text.is_null());
+    let text = text.as_mut().unwrap();
+    let value = text.get_value().as_string().unwrap().to_string();
+    CString::new(value).unwrap().into_raw()
+}