update: to-json ffi

src/to-json/src/convert.rs

@@ -1,11 +1,10 @@
-use serde_json as json;
 use crate::parser::{parser, Value};
 
 fn json_convert(content: &str) -> Result<String, String> { // convert to JSON format
     let data = match parser(content)? {
-        Value::JSON(_json) => json::to_string(&_json),
+        Value::JSON(_json) => serde_json::to_string(&_json),
-        Value::YAML(_yaml) => json::to_string(&_yaml),
+        Value::YAML(_yaml) => serde_json::to_string(&_yaml),
-        Value::TOML(_toml) => json::to_string(&_toml),
+        Value::TOML(_toml) => serde_json::to_string(&_toml),
     };
     match data {
         Ok(data) => Ok(data),

src/to-json/src/ffi.rs

@@ -1,14 +1,27 @@
+use crate::convert::to_json;
 use std::ffi::{c_char, CStr, CString};
-use crate::json::to_json;
+
+fn to_c_string(string: String) -> *const c_char { // fetch c-style ptr of string
+    CString::new(string).unwrap().into_raw()
+}
+
+unsafe fn load_c_string(ptr: *const c_char) -> String { // load string from c-style ptr
+    String::from(
+        CStr::from_ptr(ptr).to_str().unwrap()
+    )
+}
 
 #[no_mangle]
-pub unsafe extern "C" fn free_rust_string(string: *const c_char) {
+pub unsafe extern "C" fn free_rust_string(ptr: *const c_char) {
-    let _ = CString::from_raw(string as *mut _);
+    let _ = CString::from_raw(ptr as *mut _);
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn to_json_rust(content: *const c_char) -> *const c_char {
+pub unsafe extern "C" fn to_json_ffi(content: *const c_char) -> *const c_char {
-    let content: &str = CStr::from_ptr(content).to_str().unwrap();
+    let content = load_c_string(content);
-    let content: String = to_json(content); // may return empty string
+    let result = match to_json(&content) { // convert to JSON format
-    CString::new(content).unwrap().into_raw()
+        Some(data) => data,
+        None => String::new(), // convert failed -> empty string
+    };
+    to_c_string(result) // return c-style ptr
 }