Merge pull request #782 from mahkoh/jorth/fontconfig

fontconfig: add bindings

build/enums.rs

@@ -15,6 +15,9 @@ mod libinput;
 #[path = "../src/pango/consts.rs"]
 mod pango;
 
+#[path = "../src/fontconfig/consts.rs"]
+mod fontconfig;
+
 fn get_target() -> repc::Target {
     let rustc_target = env::var("TARGET").unwrap();
     repc::TARGET_MAP
@@ -148,5 +151,9 @@ pub fn main() -> anyhow::Result<()> {
     write_ty(&mut f, pango::CAIRO_OPERATORS, "cairo_operator_t")?;
     write_ty(&mut f, pango::PANGO_ELLIPSIZE_MODES, "PangoEllipsizeMode_")?;
 
+    let mut f = open("fontconfig_tys.rs")?;
+    write_ty(&mut f, fontconfig::FC_MATCH_KINDS, "FcMatchKind")?;
+    write_ty(&mut f, fontconfig::FC_RESULTS, "FcResult")?;
+
     Ok(())
 }

docs/setup.md

@@ -8,6 +8,7 @@ The following libraries must be installed before compiling Jay:
 - libgbm.so
 - libudev.so
 - libpangocairo-1.0.so
+- libfontconfig.so
 
 You must also have a C compiler (GCC or Clang) and the latest version of rust installed.
 You can install rust with [rustup](https://rustup.rs/).

src/fontconfig.rs

@@ -0,0 +1,138 @@
+use {
+    crate::fontconfig::consts::{FC_MATCH_PATTERN, FC_RESULT_MATCH},
+    run_on_drop::on_drop,
+    std::{
+        borrow::Cow,
+        ffi::{CStr, OsStr, c_char},
+        os::{
+            raw::{c_int, c_uchar},
+            unix::ffi::OsStrExt,
+        },
+        path::PathBuf,
+        ptr,
+    },
+    thiserror::Error,
+    uapi::IntoUstr,
+};
+
+mod consts;
+
+include!(concat!(env!("OUT_DIR"), "/fontconfig_tys.rs"));
+
+#[derive(Debug, Error)]
+pub enum FontconfigError {
+    #[error("FcConfigGetCurrent returned NULL")]
+    Init,
+    #[error("Could not create a pattern")]
+    CreatePattern,
+    #[error("Could not find a match")]
+    NoMatch,
+    #[error("Match has no name")]
+    NoName,
+    #[error("Match has no file")]
+    NoFile,
+}
+
+#[derive(Debug)]
+#[expect(dead_code)]
+pub struct Font {
+    pub fullname: String,
+    pub file: PathBuf,
+    pub index: Option<i32>,
+}
+
+#[expect(dead_code)]
+pub fn match_font(family: &str) -> Result<Font, FontconfigError> {
+    thread_local! {
+        static CONFIG: *mut FcConfig = FcConfigGetCurrent();
+    }
+    let config = CONFIG.with(|c| *c);
+    if config.is_null() {
+        return Err(FontconfigError::Init);
+    }
+    let family = family.into_ustr();
+    let p = FcPatternCreate();
+    if p.is_null() {
+        return Err(FontconfigError::CreatePattern);
+    }
+    let _destroy_pattern = on_drop(|| unsafe { FcPatternDestroy(p) });
+    let mut result = 0;
+    let p = unsafe {
+        FcPatternAddString(p, FC_FAMILY.as_ptr(), family.as_ptr() as _);
+        FcConfigSubstitute(config, p, FC_MATCH_PATTERN.0 as _);
+        FcDefaultSubstitute(p);
+        FcFontMatch(config, p, &mut result)
+    };
+    if p.is_null() {
+        return Err(FontconfigError::NoMatch);
+    }
+    let _destroy_pattern = on_drop(|| unsafe { FcPatternDestroy(p) });
+    if result != FC_RESULT_MATCH.0 as FcResult {
+        return Err(FontconfigError::NoMatch);
+    }
+    let get_cstr = |name: &CStr| {
+        let mut out = ptr::null_mut();
+        let res = unsafe { FcPatternGetString(p, name.as_ptr(), 0, &mut out) };
+        if res != FC_RESULT_MATCH.0 as FcResult || out.is_null() {
+            return None;
+        }
+        let cstr = unsafe { CStr::from_ptr(out.cast()) };
+        Some(cstr)
+    };
+    let get_int = |name: &CStr| {
+        let mut out = 0;
+        let res = unsafe { FcPatternGetInteger(p, name.as_ptr(), 0, &mut out) };
+        if res != FC_RESULT_MATCH.0 as FcResult {
+            return None;
+        }
+        Some(out as i32)
+    };
+    Ok(Font {
+        fullname: get_cstr(FC_FULLNAME)
+            .map(CStr::to_string_lossy)
+            .map(Cow::into_owned)
+            .ok_or(FontconfigError::NoName)?,
+        file: get_cstr(FC_FILE)
+            .map(CStr::to_bytes)
+            .map(OsStr::from_bytes)
+            .map(Into::into)
+            .ok_or(FontconfigError::NoFile)?,
+        index: get_int(FC_INDEX),
+    })
+}
+
+type FcBool = c_int;
+type FcPattern = u8;
+type FcConfig = u8;
+type FcChar8 = c_uchar;
+const FC_FAMILY: &CStr = c"family";
+const FC_FULLNAME: &CStr = c"fullname";
+const FC_FILE: &CStr = c"file";
+const FC_INDEX: &CStr = c"index";
+
+#[link(name = "fontconfig")]
+unsafe extern "C" {
+    safe fn FcConfigGetCurrent() -> *mut FcConfig;
+    safe fn FcPatternCreate() -> *mut FcPattern;
+    fn FcPatternDestroy(p: *mut FcPattern);
+    fn FcPatternAddString(p: *mut FcPattern, object: *const c_char, s: *const FcChar8) -> FcBool;
+    fn FcConfigSubstitute(config: *mut FcConfig, p: *mut FcPattern, kind: FcMatchKind) -> FcBool;
+    fn FcDefaultSubstitute(p: *mut FcPattern);
+    fn FcFontMatch(
+        config: *mut FcConfig,
+        p: *mut FcPattern,
+        result: *mut FcResult,
+    ) -> *mut FcPattern;
+    fn FcPatternGetString(
+        p: *mut FcPattern,
+        object: *const c_char,
+        id: c_int,
+        s: *mut *mut FcChar8,
+    ) -> FcResult;
+    fn FcPatternGetInteger(
+        p: *mut FcPattern,
+        object: *const c_char,
+        id: c_int,
+        i: *mut c_int,
+    ) -> FcResult;
+}

src/fontconfig/consts.rs

@@ -0,0 +1,20 @@
+#![allow(dead_code)]
+
+cenum! {
+    _FcMatchKind, FC_MATCH_KINDS;
+
+    FC_MATCH_PATTERN = 0,
+    FC_MATCH_FONT = 1,
+    FC_MATCH_SCAN = 2,
+    FC_MATCH_KIND_END = 3,
+}
+
+cenum! {
+    _FcResult, FC_RESULTS;
+
+    FC_RESULT_MATCH = 0,
+    FC_RESULT_NO_MATCH = 1,
+    FC_RESULT_TYPE_MISMATCH = 2,
+    FC_RESULT_NO_ID = 3,
+    FC_RESULT_OUT_OF_MEMORY = 4,
+}

src/main.rs

@@ -70,6 +70,7 @@ mod edid;
 mod ei;
 mod eventfd_cache;
 mod fixed;
+mod fontconfig;
 mod forker;
 mod format;
 mod gfx_api;