Add CFString conversion to/from Rust strings

crates/test-fuzz/Cargo.toml

@@ -14,6 +14,7 @@ cargo-fuzz = true
 libfuzzer-sys = "0.4"
 objc2 = { path = "../objc2" }
 objc2-foundation = { path = "../../framework-crates/objc2-foundation" }
+objc2-core-foundation = { path = "../../framework-crates/objc2-core-foundation" }
 arbitrary = { version = "1", features = ["derive"] }
 afl = { version = "0.15", optional = true }
 
@@ -38,6 +39,19 @@ fuzz-all = [
     "objc2-foundation/NSString",
     "objc2-foundation/NSZone",
     "objc2-foundation/unstable-mutation-return-null",
+    "objc2-core-foundation/CFBase",
+    "objc2-core-foundation/CFString",
+]
+
+[[bin]]
+name = "cfstring"
+path = "fuzz_targets/cfstring.rs"
+test = false
+doc = false
+bench = false
+required-features = [
+    "objc2-core-foundation/CFBase",
+    "objc2-core-foundation/CFString",
 ]
 
 [[bin]]

crates/test-fuzz/fuzz_targets/cfstring.rs

@@ -0,0 +1,17 @@
+#![cfg_attr(not(feature = "afl"), no_main)]
+use objc2_core_foundation::CFString;
+
+fn run(s: &str) {
+    let obj = CFString::from_str(s);
+    assert_eq!(obj.to_string(), s);
+}
+
+#[cfg(not(feature = "afl"))]
+libfuzzer_sys::fuzz_target!(|s: &str| run(s));
+
+#[cfg(feature = "afl")]
+fn main() {
+    afl::fuzz!(|s: &str| {
+        run(s);
+    });
+}

crates/test-ui/Cargo.toml

@@ -25,6 +25,8 @@ default = [
     "objc2-foundation/NSURLSession",
     "objc2-foundation/NSEnumerator",
     "objc2-foundation/NSDictionary",
+    "objc2-core-foundation/CFBase",
+    "objc2-core-foundation/CFString",
     "objc2/unstable-msg-send-always-comma",
 ]
 run = ["trybuild"]
@@ -40,6 +42,7 @@ trybuild = { version = "1.0.72", optional = true }
 block2 = { path = "../block2" }
 objc2 = { path = "../objc2" }
 objc2-foundation = { path = "../../framework-crates/objc2-foundation", default-features = false, features = ["std"] }
+objc2-core-foundation = { path = "../../framework-crates/objc2-core-foundation", default-features = false, features = ["std"] }
 
 # To make CI work
 [target.'cfg(not(target_vendor = "apple"))'.dependencies]

crates/test-ui/ui/cfstring_from_static_str.rs

@@ -0,0 +1,17 @@
+//! Test that a `'static` str used in `CFString` can't later be modified.
+use objc2_core_foundation::CFString;
+
+fn main() {
+    // Create a `&'static mut str`.
+    let s = String::from("xyz").leak();
+
+    // Construct a `CFString` from it.
+    let cf = CFString::from_static_str(s);
+    assert_eq!(cf.to_string(), "xyz");
+
+    // Modify the string.
+    s.make_ascii_uppercase();
+
+    // This would be invalid, since CFString is expected to be immutable.
+    assert_eq!(cf.to_string(), "XYZ");
+}

framework-crates/objc2-core-foundation/src/base.rs

@@ -115,8 +115,16 @@ unsafe impl Type for CFType {}
 
 impl fmt::Debug for CFType {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // TODO: Use `CFCopyDescription` here
-        f.debug_struct("CFType").finish_non_exhaustive()
+        #[cfg(feature = "CFString")]
+        {
+            let desc = crate::CFCopyDescription(Some(self)).expect("must have description");
+            write!(f, "{desc}")
+        }
+        #[cfg(not(feature = "CFString"))]
+        {
+            f.debug_struct("<CoreFoundation type>")
+                .finish_non_exhaustive()
+        }
     }
 }
 

framework-crates/objc2-core-foundation/src/lib.rs

@@ -27,6 +27,8 @@ mod generated;
 #[cfg(feature = "CFCGTypes")]
 mod geometry;
 mod retained;
+#[cfg(all(feature = "CFBase", feature = "CFString"))]
+mod string;
 mod type_traits;
 
 #[cfg(feature = "CFBase")]