gst-sys: add manual implementation for GstIdStr

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1531>

Cargo.lock

@@ -1458,6 +1458,7 @@ dependencies = [
 name = "gstreamer-sys"
 version = "0.24.0"
 dependencies = [
+ "cfg-if",
  "glib-sys",
  "gobject-sys",
  "libc",

gstreamer/sys/Cargo.toml

@@ -2,6 +2,7 @@
 system-deps = "7"
 
 [dependencies]
+cfg-if = "1.0"
 libc = "0.2"
 
 [dependencies.glib-sys]

gstreamer/sys/src/manual.rs

@@ -0,0 +1,111 @@
+use glib_sys::gpointer;
+use std::{fmt, mem};
+
+cfg_if::cfg_if! {
+    if #[cfg(target_pointer_width = "64")] {
+        const GST_ID_STR_PADDING_LEN: usize = 8;
+    } else if #[cfg(target_pointer_width = "32")] {
+        const GST_ID_STR_PADDING_LEN: usize = 12;
+    } else {
+        panic!("Only 32 bit and 64 bit pointers supported currently");
+    }
+}
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+pub struct GstIdStr {
+    // Internal representation is private
+    pointer: gpointer,
+    padding: [u8; GST_ID_STR_PADDING_LEN],
+}
+
+impl fmt::Debug for GstIdStr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use fmt::Write;
+
+        unsafe {
+            let pointer =
+                &*(&self.pointer as *const *mut _ as *const [u8; mem::size_of::<gpointer>()]);
+
+            let is_pretty = f.alternate();
+
+            f.write_str("GstIdStr(")?;
+            if is_pretty {
+                f.write_str("\n    ")?;
+            }
+
+            f.write_str("ascii: \"")?;
+            for &b in pointer.iter().chain(self.padding.iter()) {
+                match b {
+                    0 => break,
+                    c if c.is_ascii() => f.write_char(char::from(b))?,
+                    _ => f.write_char('<27>')?,
+                }
+            }
+
+            if is_pretty {
+                f.write_str("\",\n    ")?;
+            } else {
+                f.write_str("\", ")?;
+            }
+
+            f.write_str("hex: ")?;
+            for (i, b) in pointer.iter().chain(self.padding.iter()).enumerate() {
+                if i > 0 {
+                    f.write_char(' ')?;
+                }
+                f.write_fmt(format_args!("{b:02x}"))?;
+            }
+
+            if is_pretty {
+                f.write_str(",\n")?;
+            }
+
+            f.write_char(')')
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[cfg(feature = "v1_26")]
+    #[test]
+    fn gstidstr_debug() {
+        unsafe {
+            use std::{ffi::c_char, mem};
+
+            let mut s = mem::MaybeUninit::uninit();
+            crate::gst_id_str_init(s.as_mut_ptr());
+            let mut s = s.assume_init();
+
+            crate::gst_id_str_set(&mut s as *mut _, b"short\0" as *const u8 as *const c_char);
+            assert_eq!(
+                format!("{s:?}"),
+                r#"GstIdStr(ascii: "short", hex: 73 68 6f 72 74 00 00 00 00 00 00 00 00 00 00 00)"#,
+            );
+            assert_eq!(
+                format!("{s:#?}"),
+                r#"GstIdStr(
+    ascii: "short",
+    hex: 73 68 6f 72 74 00 00 00 00 00 00 00 00 00 00 00,
+)"#
+            );
+
+            crate::gst_id_str_set(
+                &mut s as *mut _,
+                b"utf8\xc3\xa7\0" as *const u8 as *const c_char,
+            );
+            assert_eq!(
+                format!("{s:?}"),
+                r#"GstIdStr(ascii: "utf8<66><38>", hex: 75 74 66 38 c3 a7 00 00 00 00 00 00 00 00 00 00)"#,
+            );
+            assert_eq!(
+                format!("{s:#?}"),
+                r#"GstIdStr(
+    ascii: "utf8<EFBFBD><EFBFBD>",
+    hex: 75 74 66 38 c3 a7 00 00 00 00 00 00 00 00 00 00,
+)"#
+            );
+        }
+    }
+}