Files
ghostty/src/font/GroupCacheSet.zig
2024-04-05 09:29:40 -07:00

451 lines
16 KiB
Zig

//! This structure contains a set of GroupCache instances keyed by
//! unique font configuration.
//!
//! Most terminals (surfaces) will share the same font configuration.
//! This structure allows expensive font information such as
//! the font atlas, glyph cache, font faces, etc. to be shared.
//!
//! The Ghostty renderers which use this information run on their
//! own threads so this structure is thread-safe. It expects that
//! the case where all glyphs are cached is the common case and
//! optimizes for that. When a glyph is not cached, all renderers
//! that share the same font configuration will be blocked until
//! the glyph is cached.
const GroupCacheSet = @This();
const std = @import("std");
const builtin = @import("builtin");
const assert = std.debug.assert;
const Allocator = std.mem.Allocator;
const ArenaAllocator = std.heap.ArenaAllocator;
const fontpkg = @import("main.zig");
const Discover = fontpkg.Discover;
const Style = fontpkg.Style;
const Library = fontpkg.Library;
const Metrics = fontpkg.face.Metrics;
const CodepointMap = fontpkg.CodepointMap;
const DesiredSize = fontpkg.face.DesiredSize;
const Face = fontpkg.Face;
const Group = fontpkg.Group;
const GroupCache = fontpkg.GroupCache;
const discovery = @import("discovery.zig");
const configpkg = @import("../config.zig");
const Config = configpkg.Config;
const log = std.log.scoped(.font_group_cache_set);
/// The allocator to use for all heap allocations.
alloc: Allocator,
/// The map of font configurations to GroupCache instances.
map: Map = .{},
/// The font library that is used for all font groups.
font_lib: Library,
/// Font discovery mechanism.
font_discover: ?Discover = null,
/// Initialize a new GroupCacheSet.
pub fn init(alloc: Allocator) !GroupCacheSet {
var font_lib = try Library.init();
errdefer font_lib.deinit();
return .{
.alloc = alloc,
.map = .{},
.font_lib = font_lib,
};
}
pub fn deinit(self: *GroupCacheSet) void {
var it = self.map.iterator();
while (it.next()) |entry| {
const ref = entry.value_ptr.*;
ref.cache.deinit(self.alloc);
self.alloc.destroy(ref.cache);
}
self.map.deinit(self.alloc);
if (comptime Discover != void) {
if (self.font_discover) |*v| v.deinit();
}
self.font_lib.deinit();
}
/// Initialize a GroupCache for the given font configuration. If the
/// GroupCache is not present it will be initialized with a ref count of
/// 1. If it is present, the ref count will be incremented.
///
/// This is NOT thread-safe.
pub fn groupInit(
self: *GroupCacheSet,
config: *const Config,
font_size: DesiredSize,
) !*GroupCache {
var key = try Key.init(self.alloc, config);
errdefer key.deinit();
const gop = try self.map.getOrPut(key);
if (gop.found_existing) {
// We can deinit the key because we found a cached value.
key.deinit();
// Increment our ref count and return the cache
gop.value_ptr.ref += 1;
return gop.value_ptr.cache;
}
errdefer self.map.removeByPtr(gop.key_ptr);
// A new font config, initialize the cache.
const cache = try self.alloc.create(GroupCache);
errdefer self.alloc.destroy(cache);
gop.value_ptr.* = .{
.cache = cache,
.ref = 1,
};
cache.* = try GroupCache.init(self.alloc, group: {
var group = try Group.init(self.alloc, self.font_lib, font_size);
errdefer group.deinit();
group.metric_modifiers = key.metric_modifiers;
group.codepoint_map = key.codepoint_map;
// Set our styles
group.styles.set(.bold, config.@"font-style-bold" != .false);
group.styles.set(.italic, config.@"font-style-italic" != .false);
group.styles.set(.bold_italic, config.@"font-style-bold-italic" != .false);
// Search for fonts
if (Discover != void) discover: {
const disco = try self.discover() orelse {
log.warn("font discovery not available, cannot search for fonts", .{});
break :discover;
};
group.discover = disco;
// A buffer we use to store the font names for logging.
var name_buf: [256]u8 = undefined;
inline for (@typeInfo(Style).Enum.fields) |field| {
const style = @field(Style, field.name);
for (key.descriptorsForStyle(style)) |desc| {
var disco_it = try disco.discover(self.alloc, desc);
defer disco_it.deinit();
if (try disco_it.next()) |face| {
log.info("font {s}: {s}", .{
field.name,
try face.name(&name_buf),
});
_ = try group.addFace(style, .{ .deferred = face });
} else log.warn("font-family {s} not found: {s}", .{
field.name,
desc.family.?,
});
}
}
}
// Our built-in font will be used as a backup
_ = try group.addFace(
.regular,
.{ .fallback_loaded = try Face.init(
self.font_lib,
face_ttf,
group.faceOptions(),
) },
);
_ = try group.addFace(
.bold,
.{ .fallback_loaded = try Face.init(
self.font_lib,
face_bold_ttf,
group.faceOptions(),
) },
);
// Auto-italicize if we have to.
try group.italicize();
// On macOS, always search for and add the Apple Emoji font
// as our preferred emoji font for fallback. We do this in case
// people add other emoji fonts to their system, we always want to
// prefer the official one. Users can override this by explicitly
// specifying a font-family for emoji.
if (comptime builtin.target.isDarwin()) apple_emoji: {
const disco = group.discover orelse break :apple_emoji;
var disco_it = try disco.discover(self.alloc, .{
.family = "Apple Color Emoji",
});
defer disco_it.deinit();
if (try disco_it.next()) |face| {
_ = try group.addFace(.regular, .{ .fallback_deferred = face });
}
}
// Emoji fallback. We don't include this on Mac since Mac is expected
// to always have the Apple Emoji available on the system.
if (comptime !builtin.target.isDarwin() or Discover == void) {
_ = try group.addFace(
.regular,
.{ .fallback_loaded = try Face.init(
self.font_lib,
face_emoji_ttf,
group.faceOptions(),
) },
);
_ = try group.addFace(
.regular,
.{ .fallback_loaded = try Face.init(
self.font_lib,
face_emoji_text_ttf,
group.faceOptions(),
) },
);
}
break :group group;
});
errdefer cache.deinit(self.alloc);
return gop.value_ptr.cache;
}
/// Map of font configurations to GroupCache instances. The GroupCache
/// instances are pointers that are heap allocated so that they're
/// stable pointers across hash map resizes.
pub const Map = std.HashMapUnmanaged(
Key,
RefGroupCache,
struct {
const KeyType = Key;
pub fn hash(ctx: @This(), k: KeyType) u64 {
_ = ctx;
return k.hashcode();
}
pub fn eql(ctx: @This(), a: KeyType, b: KeyType) bool {
return ctx.hash(a) == ctx.hash(b);
}
},
std.hash_map.default_max_load_percentage,
);
/// Initialize once and return the font discovery mechanism. This remains
/// initialized throughout the lifetime of the application because some
/// font discovery mechanisms (i.e. fontconfig) are unsafe to reinit.
fn discover(self: *GroupCacheSet) !?*Discover {
// If we're built without a font discovery mechanism, return null
if (comptime Discover == void) return null;
// If we initialized, use it
if (self.font_discover) |*v| return v;
self.font_discover = Discover.init();
return &self.font_discover.?;
}
/// Ref-counted GroupCache.
const RefGroupCache = struct {
cache: *GroupCache,
ref: u32 = 0,
};
/// The key used to uniquely identify a font configuration.
pub const Key = struct {
arena: ArenaAllocator,
/// The descriptors used for all the fonts added to the
/// initial group, including all styles. This is hashed
/// in order so the order matters. All users of the struct
/// should ensure that the order is consistent.
descriptors: []const discovery.Descriptor,
/// These are the offsets into the descriptors array for
/// each style. For example, bold is from
/// offsets[@intFromEnum(.bold) - 1] to
/// offsets[@intFromEnum(.bold)].
style_offsets: StyleOffsets = .{0} ** style_offsets_len,
/// The codepoint map configuration.
codepoint_map: CodepointMap,
/// The metric modifier set configuration.
metric_modifiers: Metrics.ModifierSet,
const style_offsets_len = std.enums.directEnumArrayLen(Style, 0);
const StyleOffsets = [style_offsets_len]usize;
comptime {
// We assume this throughout this structure. If this changes
// we may need to change this structure.
assert(@intFromEnum(Style.regular) == 0);
assert(@intFromEnum(Style.bold) == 1);
assert(@intFromEnum(Style.italic) == 2);
assert(@intFromEnum(Style.bold_italic) == 3);
}
pub fn init(
alloc_gpa: Allocator,
config: *const Config,
) !Key {
var arena = ArenaAllocator.init(alloc_gpa);
errdefer arena.deinit();
const alloc = arena.allocator();
var descriptors = std.ArrayList(discovery.Descriptor).init(alloc);
defer descriptors.deinit();
for (config.@"font-family".list.items) |family| {
try descriptors.append(.{
.family = family,
.style = config.@"font-style".nameValue(),
.size = config.@"font-size",
.variations = config.@"font-variation".list.items,
});
}
// In all the styled cases below, we prefer to specify an exact
// style via the `font-style` configuration. If a style is not
// specified, we use the discovery mechanism to search for a
// style category such as bold, italic, etc. We can't specify both
// because the latter will restrict the search to only that. If
// a user says `font-style = italic` for the bold face for example,
// no results would be found if we restrict to ALSO searching for
// italic.
for (config.@"font-family-bold".list.items) |family| {
const style = config.@"font-style-bold".nameValue();
try descriptors.append(.{
.family = family,
.style = style,
.size = config.@"font-size",
.bold = style == null,
.variations = config.@"font-variation".list.items,
});
}
for (config.@"font-family-italic".list.items) |family| {
const style = config.@"font-style-italic".nameValue();
try descriptors.append(.{
.family = family,
.style = style,
.size = config.@"font-size",
.italic = style == null,
.variations = config.@"font-variation".list.items,
});
}
for (config.@"font-family-bold-italic".list.items) |family| {
const style = config.@"font-style-bold-italic".nameValue();
try descriptors.append(.{
.family = family,
.style = style,
.size = config.@"font-size",
.bold = style == null,
.italic = style == null,
.variations = config.@"font-variation".list.items,
});
}
// Setup the codepoint map
const codepoint_map: CodepointMap = map: {
const map = config.@"font-codepoint-map";
if (map.map.list.len == 0) break :map .{};
const clone = try config.@"font-codepoint-map".clone(alloc);
break :map clone.map;
};
// Metric modifiers
const metric_modifiers: Metrics.ModifierSet = set: {
var set: Metrics.ModifierSet = .{};
if (config.@"adjust-cell-width") |m| try set.put(alloc, .cell_width, m);
if (config.@"adjust-cell-height") |m| try set.put(alloc, .cell_height, m);
if (config.@"adjust-font-baseline") |m| try set.put(alloc, .cell_baseline, m);
if (config.@"adjust-underline-position") |m| try set.put(alloc, .underline_position, m);
if (config.@"adjust-underline-thickness") |m| try set.put(alloc, .underline_thickness, m);
if (config.@"adjust-strikethrough-position") |m| try set.put(alloc, .strikethrough_position, m);
if (config.@"adjust-strikethrough-thickness") |m| try set.put(alloc, .strikethrough_thickness, m);
break :set set;
};
return .{
.arena = arena,
.descriptors = try descriptors.toOwnedSlice(),
.style_offsets = .{
config.@"font-family".list.items.len,
config.@"font-family-bold".list.items.len,
config.@"font-family-italic".list.items.len,
config.@"font-family-bold-italic".list.items.len,
},
.codepoint_map = codepoint_map,
.metric_modifiers = metric_modifiers,
};
}
pub fn deinit(self: *Key) void {
self.arena.deinit();
}
/// Get the descriptors for the given font style that can be
/// used with discovery.
pub fn descriptorsForStyle(
self: Key,
style: Style,
) []const discovery.Descriptor {
const idx = @intFromEnum(style);
const start: usize = if (idx == 0) 0 else self.style_offsets[idx - 1];
const end = self.style_offsets[idx];
return self.descriptors[start..end];
}
/// Hash the key with the given hasher.
pub fn hash(self: Key, hasher: anytype) void {
const autoHash = std.hash.autoHash;
autoHash(hasher, self.descriptors.len);
for (self.descriptors) |d| d.hash(hasher);
autoHash(hasher, self.codepoint_map);
autoHash(hasher, self.metric_modifiers.count());
if (self.metric_modifiers.count() > 0) {
inline for (@typeInfo(Metrics.Key).Enum.fields) |field| {
const key = @field(Metrics.Key, field.name);
if (self.metric_modifiers.get(key)) |value| {
autoHash(hasher, key);
value.hash(hasher);
}
}
}
}
/// Returns a hash code that can be used to uniquely identify this
/// action.
pub fn hashcode(self: Key) u64 {
var hasher = std.hash.Wyhash.init(0);
self.hash(&hasher);
return hasher.final();
}
};
const face_ttf = @embedFile("res/JetBrainsMono-Regular.ttf");
const face_bold_ttf = @embedFile("res/JetBrainsMono-Bold.ttf");
const face_emoji_ttf = @embedFile("res/NotoColorEmoji.ttf");
const face_emoji_text_ttf = @embedFile("res/NotoEmoji-Regular.ttf");
test "Key" {
const testing = std.testing;
const alloc = testing.allocator;
var cfg = try Config.default(alloc);
defer cfg.deinit();
var k = try Key.init(alloc, &cfg);
defer k.deinit();
try testing.expect(k.hashcode() > 0);
}
test "basics" {
const testing = std.testing;
const alloc = testing.allocator;
var set = try GroupCacheSet.init(alloc);
defer set.deinit();
}