1 files changed, 89 insertions, 0 deletions
diff --git a/libs/steam_appinfo_ffi/src/lib.rs b/libs/steam_appinfo_ffi/src/lib.rs
new file mode 100644
index 0000000..c134b97
--- /dev/null
+++ b/libs/steam_appinfo_ffi/src/lib.rs
@@ -0,0 +1,89 @@
+//! C FFI bridge to steam-vdf-parser for reading Steam's appinfo.vdf (binary,
+//! including v41 / magic 0x07564429 with string table).
+//!
+//! Exposes a single function that streams `(appid, type, name)` tuples to a
+//! C callback so the C++ side can build its own data structures without
+//! needing to know the parser's internals.
+
+use std::ffi::{CStr, CString, c_char, c_void};
+use std::fs;
+
+use steam_vdf_parser::parse_appinfo;
+
+/// Callback invoked once per app. `user` is passed through unchanged.
+/// Strings are valid for the duration of the call only — the C++ side must
+/// copy whatever it wants to keep.
+pub type SteamAppInfoCallback =
+    extern "C" fn(user: *mut c_void, appid: u32, type_: *const c_char, name: *const c_char);
+
+/// Parse the appinfo.vdf at `path_c` and call `cb(user, appid, type, name)`
+/// for every app whose `common` section is readable.
+///
+/// Returns 0 on success, negative on error:
+///   -1 = path is null / not valid UTF-8
+///   -2 = file read error
+///   -3 = parse error (unsupported magic, truncated, etc.)
+///
+/// # Safety
+/// `path_c` must be a valid null-terminated C string. `cb` must be non-null.
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn steam_appinfo_parse(
+    path_c: *const c_char,
+    user: *mut c_void,
+    cb: SteamAppInfoCallback,
+) -> i32 {
+    if path_c.is_null() {
+        return -1;
+    }
+    let path = match unsafe { CStr::from_ptr(path_c) }.to_str() {
+        Ok(s) => s,
+        Err(_) => return -1,
+    };
+
+    let data = match fs::read(path) {
+        Ok(d) => d,
+        Err(_) => return -2,
+    };
+
+    let vdf = match parse_appinfo(&data) {
+        Ok(v) => v.into_owned(),
+        Err(_) => return -3,
+    };
+
+    let root = match vdf.as_obj() {
+        Some(o) => o,
+        None => return -3,
+    };
+
+    for (app_id_str, app_value) in root.iter() {
+        let appid = match app_id_str.parse::<u32>() {
+            Ok(v) => v,
+            Err(_) => continue,
+        };
+
+        let app_obj = match app_value.as_obj() {
+            Some(o) => o,
+            None => continue,
+        };
+
+        let common = app_obj
+            .get("appinfo")
+            .and_then(|v| v.as_obj())
+            .and_then(|appinfo| appinfo.get("common"))
+            .and_then(|v| v.as_obj());
+
+        let common = match common {
+            Some(c) => c,
+            None => continue,
+        };
+
+        let type_ = common.get("type").and_then(|v| v.as_str()).unwrap_or("");
+        let name = common.get("name").and_then(|v| v.as_str()).unwrap_or("");
+
+        let type_c = CString::new(type_).unwrap_or_default();
+        let name_c = CString::new(name).unwrap_or_default();
+        cb(user, appid, type_c.as_ptr(), name_c.as_ptr());
+    }
+
+    0
+}