perf(ext/ffi): Revert UTF-8 validity check from getCString (#17741)

2 files changed, 27 insertions, 12 deletions

diff --git a/ext/ffi/repr.rs b/ext/ffi/repr.rs
index db03479dc..c21b2b0f1 100644
--- a/ext/ffi/repr.rs
+++ b/ext/ffi/repr.rs
@@ -145,14 +145,13 @@ where
   let ptr = unsafe { ptr.add(offset) };
 
   // SAFETY: Pointer is user provided.
-  let cstr = unsafe { CStr::from_ptr(ptr as *const c_char) }
-    .to_str()
-    .map_err(|_| type_error("Invalid CString pointer, not valid UTF-8"))?;
-  let value: v8::Local<v8::Value> = v8::String::new(scope, cstr)
-    .ok_or_else(|| {
-      type_error("Invalid CString pointer, string exceeds max length")
-    })?
-    .into();
+  let cstr = unsafe { CStr::from_ptr(ptr as *const c_char) }.to_bytes();
+  let value: v8::Local<v8::Value> =
+    v8::String::new_from_utf8(scope, cstr, v8::NewStringType::Normal)
+      .ok_or_else(|| {
+        type_error("Invalid CString pointer, string exceeds max length")
+      })?
+      .into();
   Ok(value.into())
 }
 
diff --git a/test_ffi/tests/test.js b/test_ffi/tests/test.js
index e45c5895b..15900e72c 100644
--- a/test_ffi/tests/test.js
+++ b/test_ffi/tests/test.js
@@ -699,10 +699,26 @@ assertEquals([...uint8Array], [
   0x00
 ]);
 
-try {
-  assertThrows(() => charView.getCString(), TypeError, "Invalid CString pointer, not valid UTF-8");
-} catch (_err) {
-  console.log("Invalid UTF-8 characters to `v8::String`:", charView.getCString());
+// Check that `getCString` works equally to `TextDecoder`
+assertEquals(charView.getCString(), new TextDecoder().decode(uint8Array.subarray(0, uint8Array.length - 1)));
+
+// Check a selection of various invalid UTF-8 sequences in C strings and verify
+// that the `getCString` API does not cause unexpected behaviour.
+for (const charBuffer of [
+  Uint8Array.from([0xA0, 0xA1, 0x00]),
+  Uint8Array.from([0xE2, 0x28, 0xA1, 0x00]),
+  Uint8Array.from([0xE2, 0x82, 0x28, 0x00]),
+  Uint8Array.from([0xF0, 0x28, 0x8C, 0xBC, 0x00]),
+  Uint8Array.from([0xF0, 0x90, 0x28, 0xBC, 0x00]),
+  Uint8Array.from([0xF0, 0x28, 0x8C, 0x28, 0x00]),
+  Uint8Array.from([0xF8, 0xA1, 0xA1, 0xA1, 0xA1, 0x00]),
+  Uint8Array.from([0xFC, 0xA1, 0xA1, 0xA1, 0xA1, 0xA1, 0x00]),
+]) {
+  const charBufferPointer = Deno.UnsafePointer.of(charBuffer);
+  const charString = Deno.UnsafePointerView.getCString(charBufferPointer);
+  const charBufferPointerArrayBuffer = new Uint8Array(Deno.UnsafePointerView.getArrayBuffer(charBufferPointer, charBuffer.length - 1));
+  assertEquals(charString, new TextDecoder().decode(charBufferPointerArrayBuffer));
+  assertEquals([...charBuffer.subarray(0, charBuffer.length - 1)], [...charBufferPointerArrayBuffer]);
 }