Add wrappers for the hb_version* functions. (#236)

This will be useful moving forward as we start to update the
library version.

harfbuzz/src/lib.rs

@@ -39,3 +39,6 @@ pub use self::language::Language;
 
 mod blob;
 pub use self::blob::Blob;
+
+mod version;
+pub use self::version::{version, version_atleast, version_string};

harfbuzz/src/version.rs

@@ -0,0 +1,52 @@
+// Copyright 2023 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use crate::sys::{hb_version, hb_version_atleast, hb_version_string};
+
+/// Returns the HarfBuzz library version.
+///
+/// # Example:
+///
+/// ```
+/// let (major, minor, patch) = harfbuzz::version();
+/// println!("HarfBuzz version {}.{}.{}", major, minor, patch);
+/// ```
+pub fn version() -> (u32, u32, u32) {
+    let mut major: u32 = 0;
+    let mut minor: u32 = 0;
+    let mut patch: u32 = 0;
+    unsafe {
+        hb_version(&mut major, &mut minor, &mut patch);
+    }
+    (major, minor, patch)
+}
+
+/// Returns true if the HarfBuzz library version is at least the given version.
+///
+/// # Example:
+///
+/// ```
+/// assert!(harfbuzz::version_atleast(2, 0, 0));
+/// ```
+pub fn version_atleast(major: u32, minor: u32, patch: u32) -> bool {
+    unsafe { hb_version_atleast(major, minor, patch) != 0 }
+}
+
+/// Returns the HarfBuzz library version as a string.
+///
+/// # Example:
+///
+/// ```
+/// println!("HarfBuzz version {}", harfbuzz::version_string());
+/// ```
+pub fn version_string() -> &'static str {
+    unsafe { core::ffi::CStr::from_ptr(hb_version_string()) }
+        .to_str()
+        .unwrap()
+}