replace zig-js-runtime

src/runtime/generate.zig

@@ -0,0 +1,229 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+// ----
+const Type = std.builtin.Type;
+
+// Union
+// -----
+
+// Generate a flatten tagged Union from a Tuple
+pub fn Union(comptime interfaces: anytype) type {
+    // @setEvalBranchQuota(10000);
+    const tuple = Tuple(interfaces){};
+    const fields = std.meta.fields(@TypeOf(tuple));
+
+    const tag_type = switch (fields.len) {
+        0 => unreachable,
+        1 => u0,
+        2 => u1,
+        3...4 => u2,
+        5...8 => u3,
+        9...16 => u4,
+        17...32 => u5,
+        33...64 => u6,
+        65...128 => u7,
+        129...256 => u8,
+        else => @compileError("Too many interfaces to generate union"),
+    };
+
+    // second iteration to generate tags
+    var enum_fields: [fields.len]Type.EnumField = undefined;
+    for (fields, 0..) |field, index| {
+        const member = @field(tuple, field.name);
+        const full_name = @typeName(member);
+        const separator = std.mem.lastIndexOfScalar(u8, full_name, '.') orelse unreachable;
+        const name = full_name[separator + 1 ..];
+        enum_fields[index] = .{
+            .name = name ++ "",
+            .value = index,
+        };
+    }
+
+    const enum_info = Type.Enum{
+        .tag_type = tag_type,
+        .fields = &enum_fields,
+        .decls = &.{},
+        .is_exhaustive = true,
+    };
+    const enum_T = @Type(.{ .@"enum" = enum_info });
+
+    // third iteration to generate union type
+    var union_fields: [fields.len]Type.UnionField = undefined;
+    for (fields, enum_fields, 0..) |field, e, index| {
+        var FT = @field(tuple, field.name);
+        if (@hasDecl(FT, "Self")) {
+            FT = *(@field(FT, "Self"));
+        }
+        union_fields[index] = .{
+            .type = FT,
+            .name = e.name,
+            .alignment = @alignOf(FT),
+        };
+    }
+
+    return @Type(.{ .@"union" = .{
+        .layout = .auto,
+        .tag_type = enum_T,
+        .fields = &union_fields,
+        .decls = &.{},
+    } });
+}
+
+// Tuple
+// -----
+
+// Flattens and depuplicates a list of nested tuples. For example
+// input: {A, B, {C, B, D}, {A, E}}
+// output {A, B, C, D, E}
+pub fn Tuple(comptime args: anytype) type {
+    @setEvalBranchQuota(100000);
+
+    const count = countInterfaces(args, 0);
+    var interfaces: [count]type = undefined;
+    _ = flattenInterfaces(args, &interfaces, 0);
+
+    const unfiltered_count, const filter_set = filterMap(count, interfaces);
+
+    var field_index: usize = 0;
+    var fields: [unfiltered_count]Type.StructField = undefined;
+
+    for (filter_set, 0..) |filter, i| {
+        if (filter) {
+            continue;
+        }
+        fields[field_index] = .{
+            .name = std.fmt.comptimePrint("{d}", .{field_index}),
+            .type = type,
+            // has to be true in order to properly capture the default value
+            .is_comptime = true,
+            .alignment = @alignOf(type),
+            .default_value_ptr = @ptrCast(&interfaces[i]),
+        };
+        field_index += 1;
+    }
+
+    return @Type(.{ .@"struct" = .{
+        .layout = .auto,
+        .fields = &fields,
+        .decls = &.{},
+        .is_tuple = true,
+    } });
+}
+
+fn countInterfaces(args: anytype, count: usize) usize {
+    var new_count = count;
+    for (@typeInfo(@TypeOf(args)).@"struct".fields) |f| {
+        const member = @field(args, f.name);
+        if (@TypeOf(member) == type) {
+            new_count += 1;
+        } else {
+            new_count = countInterfaces(member, new_count);
+        }
+    }
+    return new_count;
+}
+
+fn flattenInterfaces(args: anytype, interfaces: []type, index: usize) usize {
+    var new_index = index;
+    for (@typeInfo(@TypeOf(args)).@"struct".fields) |f| {
+        const member = @field(args, f.name);
+        if (@TypeOf(member) == type) {
+            interfaces[new_index] = member;
+            new_index += 1;
+        } else {
+            new_index = flattenInterfaces(member, interfaces, new_index);
+        }
+    }
+    return new_index;
+}
+
+fn filterMap(comptime count: usize, interfaces: [count]type) struct { usize, [count]bool } {
+    var map: [count]bool = undefined;
+    var unfiltered_count: usize = 0;
+    outer: for (interfaces, 0..) |iface, i| {
+        for (interfaces[i + 1 ..]) |check| {
+            if (iface == check) {
+                map[i] = true;
+                continue :outer;
+            }
+        }
+        map[i] = false;
+        unfiltered_count += 1;
+    }
+    return .{ unfiltered_count, map };
+}
+
+test "generate.Union" {
+    const Astruct = struct {
+        pub const Self = Other;
+        const Other = struct {};
+    };
+
+    const Bstruct = struct {
+        value: u8 = 0,
+    };
+
+    const Cstruct = struct {
+        value: u8 = 0,
+    };
+
+    const value = Union(.{ Astruct, Bstruct, .{Cstruct} });
+    const ti = @typeInfo(value).@"union";
+    try std.testing.expectEqual(3, ti.fields.len);
+    try std.testing.expectEqualStrings("*runtime.generate.test.generate.Union.Astruct.Other", @typeName(ti.fields[0].type));
+    try std.testing.expectEqualStrings(ti.fields[0].name, "Astruct");
+    try std.testing.expectEqual(Bstruct, ti.fields[1].type);
+    try std.testing.expectEqualStrings(ti.fields[1].name, "Bstruct");
+    try std.testing.expectEqual(Cstruct, ti.fields[2].type);
+    try std.testing.expectEqualStrings(ti.fields[2].name, "Cstruct");
+}
+
+test "generate.Tuple" {
+    const Astruct = struct {};
+
+    const Bstruct = struct {
+        value: u8 = 0,
+    };
+
+    const Cstruct = struct {
+        value: u8 = 0,
+    };
+
+    {
+        const tuple = Tuple(.{ Astruct, Bstruct }){};
+        const ti = @typeInfo(@TypeOf(tuple)).@"struct";
+        try std.testing.expectEqual(true, ti.is_tuple);
+        try std.testing.expectEqual(2, ti.fields.len);
+        try std.testing.expectEqual(Astruct, tuple.@"0");
+        try std.testing.expectEqual(Bstruct, tuple.@"1");
+    }
+
+    {
+        // dedupe
+        const tuple = Tuple(.{ Cstruct, Astruct, .{Astruct}, Bstruct, .{ Astruct, .{ Astruct, Bstruct } } }){};
+        const ti = @typeInfo(@TypeOf(tuple)).@"struct";
+        try std.testing.expectEqual(true, ti.is_tuple);
+        try std.testing.expectEqual(3, ti.fields.len);
+        try std.testing.expectEqual(Cstruct, tuple.@"0");
+        try std.testing.expectEqual(Astruct, tuple.@"1");
+        try std.testing.expectEqual(Bstruct, tuple.@"2");
+    }
+}