Refactor string handling in OfflineRecognizerResult and TTS modules

Author: thewh1teagle

crates/sherpa-rs/src/lib.rs

@@ -98,8 +98,8 @@ pub struct OfflineRecognizerResult {
 
 impl OfflineRecognizerResult {
     fn new(result: &sherpa_rs_sys::SherpaOnnxOfflineRecognizerResult) -> Self {
-        let lang = cstr_to_string(result.lang);
-        let text = cstr_to_string(result.text);
+        let lang = unsafe { cstr_to_string(result.lang) };
+        let text = unsafe { cstr_to_string(result.text) };
         let count = result.count.try_into().unwrap();
         let timestamps = if result.timestamps.is_null() {
             Vec::new()

crates/sherpa-rs/src/tts/mod.rs

@@ -2,13 +2,15 @@ mod kokoro;
 mod matcha;
 mod vits;
 
+use std::ffi::CString;
+
 use eyre::{bail, Result};
 
 pub use kokoro::{KokoroTts, KokoroTtsConfig};
 pub use matcha::{MatchaTts, MatchaTtsConfig};
 pub use vits::{VitsTts, VitsTtsConfig};
 
-use crate::utils::{cstring_from_str, RawCStr};
+use crate::utils::cstring_from_str;
 
 #[derive(Debug)]
 pub struct TtsAudio {
@@ -26,8 +28,8 @@ pub struct CommonTtsConfig {
 }
 
 pub struct CommonTtsRaw {
-    pub rule_fars: Option<RawCStr>,
-    pub rule_fsts: Option<RawCStr>,
+    pub rule_fars: Option<CString>,
+    pub rule_fsts: Option<CString>,
     pub max_num_sentences: i32,
 }
 

crates/sherpa-rs/src/utils.rs

@@ -1,48 +1,13 @@
 use std::ffi::{c_char, CString};
 
-pub fn cstring_from_str(s: &str) -> RawCStr {
-    RawCStr::new(s)
+pub fn cstring_from_str(s: &str) -> CString {
+    CString::new(s).expect("CString::new failed")
 }
 
-pub fn cstr_to_string(ptr: *const c_char) -> String {
-    unsafe {
-        if ptr.is_null() {
-            String::new()
-        } else {
-            std::ffi::CStr::from_ptr(ptr).to_string_lossy().into_owned()
-        }
-    }
-}
-
-pub struct RawCStr {
-    ptr: *mut std::ffi::c_char,
-}
-
-impl RawCStr {
-    /// Creates a new `CStr` from a given Rust string slice.
-    pub fn new(s: &str) -> Self {
-        let cstr = CString::new(s).expect("CString::new failed");
-        let ptr = cstr.into_raw();
-        Self { ptr }
-    }
-
-    /// Returns the raw pointer to the internal C string.
-    ///
-    /// # Safety
-    /// This function only returns the raw pointer and does not transfer ownership.
-    /// The pointer remains valid as long as the `CStr` instance exists.
-    /// Be cautious not to deallocate or modify the pointer after using `CStr::new`.
-    pub fn as_ptr(&self) -> *const c_char {
-        self.ptr
-    }
-}
-
-impl Drop for RawCStr {
-    fn drop(&mut self) {
-        if !self.ptr.is_null() {
-            unsafe {
-                let _ = CString::from_raw(self.ptr);
-            }
-        }
+pub unsafe fn cstr_to_string(ptr: *const c_char) -> String {
+    if ptr.is_null() {
+        String::new()
+    } else {
+        std::ffi::CStr::from_ptr(ptr).to_string_lossy().into_owned()
     }
 }