Use NonNull for jsstr_to_string, latin1_to_string (#605)

Signed-off-by: sagudev <[email protected]>

Author: sagudev

mozjs/src/conversions.rs

@@ -48,6 +48,7 @@ use log::debug;
 use mozjs_sys::jsgc::Rooted;
 use std::borrow::Cow;
 use std::mem;
+use std::ptr::NonNull;
 use std::rc::Rc;
 use std::{ptr, slice};
 
@@ -527,11 +528,11 @@ impl FromJSValConvertible for f64 {
 
 /// Converts a `JSString`, encoded in "Latin1" (i.e. U+0000-U+00FF encoded as 0x00-0xFF) into a
 /// `String`.
-pub unsafe fn latin1_to_string(cx: *mut JSContext, s: *mut JSString) -> String {
-    assert!(JS_DeprecatedStringHasLatin1Chars(s));
+pub unsafe fn latin1_to_string(cx: *mut JSContext, s: NonNull<JSString>) -> String {
+    assert!(JS_DeprecatedStringHasLatin1Chars(s.as_ptr()));
 
     let mut length = 0;
-    let chars = JS_GetLatin1StringCharsAndLength(cx, ptr::null(), s, &mut length);
+    let chars = JS_GetLatin1StringCharsAndLength(cx, ptr::null(), s.as_ptr(), &mut length);
     assert!(!chars.is_null());
 
     let chars = slice::from_raw_parts(chars, length as usize);
@@ -541,13 +542,13 @@ pub unsafe fn latin1_to_string(cx: *mut JSContext, s: *mut JSString) -> String {
 }
 
 /// Converts a `JSString` into a `String`, regardless of used encoding.
-pub unsafe fn jsstr_to_string(cx: *mut JSContext, jsstr: *mut JSString) -> String {
-    if JS_DeprecatedStringHasLatin1Chars(jsstr) {
+pub unsafe fn jsstr_to_string(cx: *mut JSContext, jsstr: NonNull<JSString>) -> String {
+    if JS_DeprecatedStringHasLatin1Chars(jsstr.as_ptr()) {
         return latin1_to_string(cx, jsstr);
     }
 
     let mut length = 0;
-    let chars = JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), jsstr, &mut length);
+    let chars = JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), jsstr.as_ptr(), &mut length);
     assert!(!chars.is_null());
     let char_vec = slice::from_raw_parts(chars, length as usize);
     String::from_utf16_lossy(char_vec)
@@ -588,10 +589,10 @@ impl FromJSValConvertible for String {
         _: (),
     ) -> Result<ConversionResult<String>, ()> {
         let jsstr = ToString(cx, value);
-        if jsstr.is_null() {
+        let Some(jsstr) = NonNull::new(jsstr) else {
             debug!("ToString failed");
             return Err(());
-        }
+        };
         Ok(jsstr_to_string(cx, jsstr)).map(ConversionResult::Success)
     }
 }

mozjs/src/rust.rs

@@ -1073,7 +1073,7 @@ impl<'a> CapturedJSStack<'a> {
                 return None;
             }
 
-            Some(jsstr_to_string(self.cx, string_handle.get()))
+            Some(jsstr_to_string(self.cx, NonNull::new(string_handle.get())?))
         }
     }
 

mozjs/tests/external_string.rs

@@ -4,6 +4,7 @@
 
 use std::ffi::c_void;
 use std::ptr;
+use std::ptr::NonNull;
 
 use mozjs::conversions::jsstr_to_string;
 use mozjs::glue::{CreateJSExternalStringCallbacks, JSExternalStringCallbacksTraps};
@@ -50,7 +51,10 @@ fn external_string() {
             latin1_base.len(),
             callbacks
         ));
-        assert_eq!(jsstr_to_string(context, latin1_jsstr.get()), latin1_base);
+        assert_eq!(
+            jsstr_to_string(context, NonNull::new(latin1_jsstr.get()).unwrap()),
+            latin1_base
+        );
 
         let utf16_base = "test utf-16 $€ \u{10437}\u{24B62}";
         let utf16_boxed = utf16_base
@@ -70,7 +74,10 @@ fn external_string() {
             utf16_len,
             callbacks
         ));
-        assert_eq!(jsstr_to_string(context, utf16_jsstr.get()), utf16_base);
+        assert_eq!(
+            jsstr_to_string(context, NonNull::new(utf16_jsstr.get()).unwrap()),
+            utf16_base
+        );
     }
 }