LibUnicode: Generate FFI bindings with cbindgen

This places the exported structs and functions in the Unicode::FFI
namespace.

Cargo.lock

@@ -383,6 +383,7 @@ name = "libunicode_rust"
 version = "0.1.0"
 dependencies = [
  "calendrical_calculations",
+ "cbindgen",
  "icu_calendar",
 ]
 

Libraries/LibUnicode/Calendar.cpp

@@ -5,47 +5,7 @@
  */
 
 #include <LibUnicode/Calendar.h>
-
-struct FfiISODate {
-    i32 year;
-    u8 month;
-    u8 day;
-};
-
-struct FfiOptionalISODate {
-    FfiISODate iso_date;
-    bool has_value;
-};
-
-struct FfiCalendarDate {
-    i32 year;
-    u8 month;
-    u8 month_code[5];
-    u8 month_code_length;
-    u8 day;
-    u8 day_of_week;
-    u16 day_of_year;
-    u8 days_in_week;
-    u8 days_in_month;
-    u16 days_in_year;
-    u8 months_in_year;
-    bool in_leap_year;
-};
-
-extern "C" {
-
-FfiCalendarDate icu_iso_date_to_calendar_date(u8 const* calendar, size_t calendar_length, i32 iso_year, u8 iso_month, u8 iso_day);
-FfiOptionalISODate icu_calendar_date_to_iso_date(u8 const* calendar, size_t calendar_length, i32 arithmetic_year, u8 ordinal_month, u8 day);
-
-FfiOptionalISODate icu_iso_year_and_month_code_to_iso_date(u8 const* calendar, size_t calendar_length, i32 iso_year, u8 const* month_code, size_t month_code_length, u8 day);
-FfiOptionalISODate icu_calendar_year_and_month_code_to_iso_date(u8 const* calendar, size_t calendar_length, i32 arithmetic_year, u8 const* month_code, size_t month_code_length, u8 day);
-
-u8 icu_calendar_months_in_year(u8 const* calendar, size_t calendar_length, i32 arithmetic_year);
-u8 icu_calendar_days_in_month(u8 const* calendar, size_t calendar_length, i32 arithmetic_year, u8 ordinal_month);
-u8 icu_calendar_max_days_in_month_code(u8 const* calendar, size_t calendar_length, u8 const* month_code, size_t month_code_length);
-bool icu_year_contains_month_code(u8 const* calendar, size_t calendar_length, i32 arithmetic_year, u8 const* month_code, size_t month_code_length);
-
-} // extern "C"
+#include <LibUnicode/RustFFI.h>
 
 namespace Unicode {
 
@@ -126,7 +86,7 @@ String create_month_code(u8 month_number, bool is_leap_month)
 
 CalendarDate iso_date_to_calendar_date(String const& calendar, ISODate iso_date)
 {
-    auto result = icu_iso_date_to_calendar_date(calendar.bytes().data(), calendar.bytes().size(), iso_date.year, iso_date.month, iso_date.day);
+    auto result = FFI::icu_iso_date_to_calendar_date(calendar.bytes().data(), calendar.bytes().size(), iso_date.year, iso_date.month, iso_date.day);
 
     return CalendarDate {
         .era = {},
@@ -148,7 +108,7 @@ CalendarDate iso_date_to_calendar_date(String const& calendar, ISODate iso_date)
 
 Optional<ISODate> calendar_date_to_iso_date(String const& calendar, i32 year, u8 month, u8 day)
 {
-    auto result = icu_calendar_date_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), year, month, day);
+    auto result = FFI::icu_calendar_date_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), year, month, day);
     if (!result.has_value)
         return {};
 
@@ -157,7 +117,7 @@ Optional<ISODate> calendar_date_to_iso_date(String const& calendar, i32 year, u8
 
 Optional<ISODate> iso_year_and_month_code_to_iso_date(String const& calendar, i32 year, StringView month_code, u8 day)
 {
-    auto result = icu_iso_year_and_month_code_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), year, month_code.bytes().data(), month_code.length(), day);
+    auto result = FFI::icu_iso_year_and_month_code_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), year, month_code.bytes().data(), month_code.length(), day);
     if (!result.has_value)
         return {};
 
@@ -166,7 +126,7 @@ Optional<ISODate> iso_year_and_month_code_to_iso_date(String const& calendar, i3
 
 Optional<ISODate> calendar_year_and_month_code_to_iso_date(String const& calendar, i32 arithmetic_year, StringView month_code, u8 day)
 {
-    auto result = icu_calendar_year_and_month_code_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, month_code.bytes().data(), month_code.length(), day);
+    auto result = FFI::icu_calendar_year_and_month_code_to_iso_date(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, month_code.bytes().data(), month_code.length(), day);
     if (!result.has_value)
         return {};
 
@@ -175,22 +135,22 @@ Optional<ISODate> calendar_year_and_month_code_to_iso_date(String const& calenda
 
 u8 calendar_months_in_year(String const& calendar, i32 arithmetic_year)
 {
-    return icu_calendar_months_in_year(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year);
+    return FFI::icu_calendar_months_in_year(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year);
 }
 
 u8 calendar_days_in_month(String const& calendar, i32 arithmetic_year, u8 ordinal_month)
 {
-    return icu_calendar_days_in_month(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, ordinal_month);
+    return FFI::icu_calendar_days_in_month(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, ordinal_month);
 }
 
 u8 calendar_max_days_in_month_code(String const& calendar, StringView month_code)
 {
-    return icu_calendar_max_days_in_month_code(calendar.bytes().data(), calendar.bytes().size(), month_code.bytes().data(), month_code.length());
+    return FFI::icu_calendar_max_days_in_month_code(calendar.bytes().data(), calendar.bytes().size(), month_code.bytes().data(), month_code.length());
 }
 
 bool calendar_year_contains_month_code(String const& calendar, i32 arithmetic_year, StringView month_code)
 {
-    return icu_year_contains_month_code(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, month_code.bytes().data(), month_code.length());
+    return FFI::icu_year_contains_month_code(calendar.bytes().data(), calendar.bytes().size(), arithmetic_year, month_code.bytes().data(), month_code.length());
 }
 
 }

Libraries/LibUnicode/Rust/Cargo.toml

@@ -11,3 +11,6 @@ crate-type = ["staticlib"]
 [dependencies]
 calendrical_calculations = "0.2"
 icu_calendar = { version = "2.1.1", features = ["compiled_data"] }
+
+[build-dependencies]
+cbindgen = "0.29"

Libraries/LibUnicode/Rust/build.rs

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2026-present, the Ladybird developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+use std::env;
+use std::error::Error;
+use std::path::PathBuf;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR")?);
+    let out_dir = PathBuf::from(env::var("OUT_DIR")?);
+
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=cbindgen.toml");
+
+    let ffi_out_dir = env::var("FFI_OUTPUT_DIR")
+        .map(PathBuf::from)
+        .unwrap_or_else(|_| out_dir.clone());
+
+    cbindgen::generate(manifest_dir).map_or_else(
+        |error| match error {
+            cbindgen::Error::ParseSyntaxError { .. } => {}
+            e => panic!("{e:?}"),
+        },
+        |bindings| {
+            bindings.write_to_file(ffi_out_dir.join("RustFFI.h"));
+        },
+    );
+
+    Ok(())
+}

Libraries/LibUnicode/Rust/cbindgen.toml

@@ -0,0 +1,17 @@
+language = "C++"
+header = """/*
+ * Copyright (c) 2026-present, the Ladybird developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */"""
+pragma_once = true
+include_version = true
+namespaces = ["Unicode", "FFI"]
+line_length  = 120
+tab_width = 4
+no_includes = true
+sys_includes = ["stdint.h", "stddef.h"]
+usize_is_size_t = true
+
+[export.mangle]
+rename_types = "PascalCase"

Libraries/LibUnicode/Rust/src/lib.rs

@@ -4,4 +4,4 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-mod calendar;
+pub mod calendar;