use std::collections::HashSet;
use std::hash::Hasher;
use std::io::Error;
use rustc_hash::FxHasher;
use write_fonts::FontWrite;
use write_fonts::dump_table;
use write_fonts::read::TopLevelTable;
use write_fonts::validate::Validate;
use crate::pipeline::TtfGlyphCache;
use crate::svg::types::ProcessedGlyph;
pub(super) fn compiled_glyph_cache_key(glyph: &ProcessedGlyph, advance_width: u16) -> u64 {
let mut hasher = FxHasher::default();
match glyph.ttf_path_hash {
Some(path_hash) => hasher.write_u64(path_hash),
None => hasher.write(glyph.path_data.as_bytes()),
}
hasher.write_u16(advance_width);
hasher.finish()
}
pub(super) fn dump_cached_ttf_table<T>(
cache: &mut Option<&mut TtfGlyphCache>,
used_table_keys: &mut HashSet<u64>,
cache_key: impl FnOnce() -> u64,
table: &T,
name: &str,
) -> Result<([u8; 4], Vec<u8>), Error>
where
T: FontWrite + TopLevelTable + Validate,
{
let Some(cache) = cache.as_deref_mut() else {
return dump_ttf_table(table, name);
};
let cache_key = cache_key();
used_table_keys.insert(cache_key);
if let Some(cached) = cache.tables.get(&cache_key) {
return Ok(cached.clone());
}
#[cfg(test)]
{
cache.table_compile_count += 1;
}
let dumped = dump_ttf_table(table, name)?;
cache.tables.insert(cache_key, dumped.clone());
Ok(dumped)
}
pub(super) fn table_cache_key(tag: &[u8; 4], hash_inputs: impl FnOnce(&mut FxHasher)) -> u64 {
let mut hasher = FxHasher::default();
hasher.write(tag);
hash_inputs(&mut hasher);
hasher.finish()
}
pub(super) fn hash_option_str(hasher: &mut FxHasher, value: Option<&str>) {
match value {
Some(value) => {
hasher.write_u8(1);
hash_str(hasher, value);
}
None => hasher.write_u8(0),
}
}
pub(super) fn hash_str(hasher: &mut FxHasher, value: &str) {
hasher.write_usize(value.len());
hasher.write(value.as_bytes());
}
pub(super) fn dump_ttf_table<T>(table: &T, name: &str) -> Result<([u8; 4], Vec<u8>), Error>
where
T: FontWrite + TopLevelTable + Validate,
{
dump_table(table)
.map(|bytes| (T::TAG.to_be_bytes(), bytes))
.map_err(|error| Error::other(format!("Failed to add {name} table: {error:?}")))
}