tiny.choir.product.entity

1const std = @import("std");2const revision = @import("root.zig").revision;3const bytecode = @import("../bytecode/root.zig");45/// A retained view owns only immutable bytes and bytecode lookup metadata.6pub const Image = opaque {7    pub fn create(8        allocator: std.mem.Allocator,9        published: *const revision.Revision,10        limits: bytecode.image.Limits,11        expected_version: u32,12    ) !*Image {13        const retained = try published.retain();14        errdefer retained.release();15        const state = try allocator.create(ImageData);16        errdefer allocator.destroy(state);17        var reader = try revision.record.Reader.init(published.view().exact.image);18        if (try reader.readInt(u32) != expected_version) return error.UnknownSchema;19        const count = try reader.readCount();20        if (count > limits.entities) return error.ImageLimit;21        const roots = try allocator.alloc(*bytecode.image.Index, count);22        errdefer allocator.free(roots);23        var initialized: usize = 0;24        errdefer for (roots[0..initialized]) |index| index.destroy();25        for (roots) |*index| {26            index.* = try bytecode.image.Index.create(allocator, try reader.readBlob(), limits);27            initialized += 1;28        }29        state.* = .{30            .allocator = allocator,31            .revision = retained,32            .roots = roots,33            .stage = try reader.readBlob(),34        };35        if (!reader.atEnd()) return error.InvalidRecord;36        return @ptrCast(state);37    }3839    pub fn destroy(self: *Image) void {40        const state = imageData(self);41        for (state.roots) |index| index.destroy();42        state.allocator.free(state.roots);43        state.revision.release();44        state.allocator.destroy(state);45    }4647    pub fn root(self: *const Image, ordinal: u32) ?bytecode.image.View {48        const state: *const ImageData = @ptrCast(@alignCast(self));49        if (ordinal >= state.roots.len) return null;50        return state.roots[ordinal].view();51    }5253    pub fn stage(self: *const Image) []const u8 {54        const state: *const ImageData = @ptrCast(@alignCast(self));55        return state.stage;56    }5758    pub fn operation(59        self: *const Image,60        ref: revision.store.Entity,61    ) !Located(bytecode.image.Operation) {62        return self.locate(ref, .operation, "operations", bytecode.image.Operation);63    }6465    pub fn block(self: *const Image, ref: revision.store.Entity) !Located(bytecode.image.Block) {66        return self.locate(ref, .block, "blocks", bytecode.image.Block);67    }6869    pub fn value(self: *const Image, ref: revision.store.Entity) !Located(bytecode.image.Value) {70        return self.locate(ref, .value, "values", bytecode.image.Value);71    }7273    pub fn region(self: *const Image, ref: revision.store.Entity) !Located(bytecode.image.Region) {74        return self.locate(ref, .region, "regions", bytecode.image.Region);75    }7677    pub fn attribute(self: *const Image, ref: revision.store.Entity) !Located([]const u8) {78        return self.locate(ref, .attribute, "attributes", []const u8);79    }8081    fn locate(82        self: *const Image,83        ref: revision.store.Entity,84        comptime namespace: revision.record.Namespace,85        comptime field: []const u8,86        comptime T: type,87    ) !Located(T) {88        const state: *const ImageData = @ptrCast(@alignCast(self));89        if (!ref.revision.eql(state.revision)) return error.StaleEntity;90        if (ref.namespace != namespace) return error.InvalidEntity;91        var ordinal = ref.ordinal;92        for (state.roots, 0..) |index, root_ordinal| {93            const items = @field(index.view(), field);94            if (ordinal < items.len) return .{95                .root = @intCast(root_ordinal),96                .value = items[ordinal],97            };98            ordinal -= @intCast(items.len);99        }100        return error.InvalidEntity;101    }102};103104pub fn Located(comptime T: type) type {105    return struct { root: u32, value: T };106}107108const ImageData = struct {109    allocator: std.mem.Allocator,110    revision: *const revision.Revision,111    roots: []*bytecode.image.Index,112    stage: []const u8,113};114115fn imageData(image: *Image) *ImageData {116    return @ptrCast(@alignCast(image));117}

1pub const entity = @import("entity.zig");