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Zig
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331const std = @import("std");const zqlite = @import("zqlite");const c = std.c;const a = std.heap.c_allocator;const page_size = 8192;const max_extent = 16 * 1024 * 1024;const max_key = 8193;const queries = [_][]const u8{ "SELECT did,blob FROM actor_compact_base ORDER BY did", "SELECT key,dids FROM prefix_top_base ORDER BY key",};
const Stats = extern struct { keys: u64 = 0, verified_keys: u64 = 0, pages: u64 = 0, oversized_pages: u64 = 0,};
fn writeAll(fd: c.fd_t, bytes: []const u8) !void { var pos: usize = 0; while (pos < bytes.len) { const n = c.write(fd, bytes[pos..].ptr, bytes.len - pos); if (n < 0 and c.errno(n) == .INTR) continue; if (n <= 0) return error.WriteFailed; pos += @intCast(n); }}
fn readAll(fd: c.fd_t, bytes: []u8, offset: usize) !void { var pos: usize = 0; while (pos < bytes.len) { const n = c.pread(fd, bytes[pos..].ptr, bytes.len - pos, @intCast(offset + pos)); if (n < 0 and c.errno(n) == .INTR) continue; if (n <= 0) return error.TruncatedRead; pos += @intCast(n); }}
fn put(comptime T: type, bytes: []u8, offset: usize, value: usize) void { std.mem.writeInt(T, bytes[offset..][0..@sizeOf(T)], @intCast(value), .little);}
fn get(comptime T: type, bytes: []const u8, offset: usize) !usize { if (offset > bytes.len or bytes.len - offset < @sizeOf(T)) return error.TruncatedField; return @intCast(std.mem.readInt(T, bytes[offset..][0..@sizeOf(T)], .little));}
fn varint(bytes: []u8, value: usize) usize { var v = value; var pos: usize = 0; while (v >= 128) : (pos += 1) { bytes[pos] = @as(u8, @intCast(v & 127)) | 128; v >>= 7; } bytes[pos] = @intCast(v); return pos + 1;}
fn readVarint(bytes: []const u8, pos: *usize) !usize { var value: usize = 0; for ([_]u6{ 0, 7, 14 }) |shift| { if (pos.* >= bytes.len) return error.TruncatedVarint; const byte = bytes[pos.*]; pos.* += 1; value |= @as(usize, byte & 127) << shift; if (byte & 128 == 0) { if (value > max_key) return error.KeyTooLong; return value; } } return error.InvalidVarint;}
const Packer = struct { entries: [2 * max_key]u8 = undefined, entry_len: usize = 0, postings: []u8, page: []u8, posting_len: usize = 0, restarts: [4096]u16 = undefined, patches: [4096]struct { pos: u16, posting: u16 } = undefined, count: usize = 0, previous: [max_key]u8 = undefined, previous_len: usize = 0, first: [max_key]u8 = undefined, first_len: usize = 0, seen: std.StringHashMapUnmanaged(u16) = .empty, roots: std.ArrayList(u8) = .empty, offsets: std.ArrayList(u8) = .empty, bytes_written: usize = 0, stats: Stats = .{}, fd: c.fd_t,
fn init(fd: c.fd_t) !Packer { const postings = try a.alloc(u8, max_extent); errdefer a.free(postings); return .{ .fd = fd, .postings = postings, .page = try a.alloc(u8, max_extent) }; }
fn deinit(self: *Packer) void { a.free(self.postings); a.free(self.page); self.seen.deinit(a); self.roots.deinit(a); self.offsets.deinit(a); }
fn add(self: *Packer, key: []const u8, blob: []const u8) !void { if (key.len == 0 or key.len > max_key or blob.len > max_extent) return error.SourceBounds; while (true) { var shared: usize = 0; if (self.count % 16 != 0) { while (shared < @min(key.len, self.previous_len) and key[shared] == self.previous[shared]) : (shared += 1) {} } var prefix: [6]u8 = undefined; var n = varint(&prefix, shared); n += varint(prefix[n..], key.len - shared); const entry_size = n + 2 + key.len - shared; const known = self.seen.get(blob); const posting_size = if (known == null) 4 + blob.len else 0; const used = 16 + 2 * ((self.count + 16) / 16) + self.entry_len + entry_size + self.posting_len + posting_size; if (self.count > 0 and used > page_size) { try self.flush(); continue; } if (used > max_extent) return error.ExtentTooLarge; if (self.count == 0) { @memcpy(self.first[0..key.len], key); self.first_len = key.len; } if (self.count % 16 == 0) self.restarts[self.count / 16] = @intCast(self.entry_len); @memcpy(self.entries[self.entry_len..][0..n], prefix[0..n]); self.entry_len += n; const posting = known orelse blk: { const offset = self.posting_len; put(u32, self.postings, offset, blob.len); @memcpy(self.postings[offset + 4 ..][0..blob.len], blob); try self.seen.put(a, self.postings[offset + 4 ..][0..blob.len], @intCast(offset)); self.posting_len += 4 + blob.len; break :blk @as(u16, @intCast(offset)); }; self.patches[self.count] = .{ .pos = @intCast(self.entry_len), .posting = posting }; self.entry_len += 2; @memcpy(self.entries[self.entry_len..][0 .. key.len - shared], key[shared..]); self.entry_len += key.len - shared; @memcpy(self.previous[0..key.len], key); self.previous_len = key.len; self.count += 1; self.stats.keys += 1; if (used > page_size) try self.flush(); return; } }
fn flush(self: *Packer) !void { if (self.count == 0) return; const groups = (self.count + 15) / 16; const key_start = 16 + 2 * groups; const key_end = key_start + self.entry_len; const used = key_end + self.posting_len; const extent = @max(page_size, std.mem.alignForward(usize, used, 4096)); if (extent > max_extent or (extent > page_size and self.count != 1)) return error.ExtentTooLarge; var header: [16 + 4096 * 2]u8 = @splat(0); put(u32, &header, 0, self.count); put(u32, &header, 4, key_end); put(u32, &header, 8, used); for (0..groups) |i| put(u16, &header, 16 + 2 * i, key_start + self.restarts[i]); for (self.patches[0..self.count]) |patch| put(u16, &self.entries, patch.pos, key_end + patch.posting); if (self.roots.items.len + self.first_len + 10 > std.math.maxInt(u32)) return error.DirectoryTooLarge; var offset: [4]u8 = undefined; put(u32, &offset, 0, self.roots.items.len); try self.offsets.appendSlice(a, &offset); var root: [max_key + 10]u8 = undefined; put(u16, &root, 0, self.first_len); @memcpy(root[2..][0..self.first_len], self.first[0..self.first_len]); put(u64, &root, self.first_len + 2, self.bytes_written); try self.roots.appendSlice(a, root[0 .. self.first_len + 10]); @memcpy(self.page[0..key_start], header[0..key_start]); @memcpy(self.page[key_start..key_end], self.entries[0..self.entry_len]); @memcpy(self.page[key_end..used], self.postings[0..self.posting_len]); @memset(self.page[used..extent], 0); try writeAll(self.fd, self.page[0..extent]); self.bytes_written += extent; self.stats.pages += 1; self.stats.oversized_pages += @intFromBool(extent > page_size); self.entry_len = 0; self.posting_len = 0; self.count = 0; self.previous_len = 0; self.seen.clearRetainingCapacity(); }
fn finish(self: *Packer, path: [*:0]const u8) !void { try self.flush(); var terminal: [4]u8 = undefined; put(u32, &terminal, 0, self.roots.items.len); try self.offsets.appendSlice(a, &terminal); const records = 80 + self.offsets.items.len; const page_data = std.mem.alignForward(usize, records + self.roots.items.len, 4096); var header: [80]u8 = @splat(0); @memcpy(header[0..8], "FLATPX05"); put(u32, &header, 8, 5); put(u32, &header, 12, self.stats.pages); put(u64, &header, 24, records); put(u64, &header, 32, page_data); put(u64, &header, 40, page_data + self.bytes_written); const fd = c.open(path, .{ .ACCMODE = .WRONLY, .CREAT = true, .EXCL = true }, @as(c.mode_t, 0o600)); if (fd < 0) return error.CreateFailed; defer _ = c.close(fd); try writeAll(fd, &header); try writeAll(fd, self.offsets.items); try writeAll(fd, self.roots.items); const zeros: [4096]u8 = @splat(0); try writeAll(fd, zeros[0 .. page_data - records - self.roots.items.len]); const buffer = try a.alloc(u8, 1024 * 1024); defer a.free(buffer); var pos: usize = 0; while (pos < self.bytes_written) { const chunk = buffer[0..@min(buffer.len, self.bytes_written - pos)]; try readAll(self.fd, chunk, pos); try writeAll(fd, chunk); pos += chunk.len; } }};
fn pack(source: [*:0]const u8, side: [*:0]const u8, scratch: [*:0]const u8) !Stats { const db = try zqlite.open(source, zqlite.OpenFlags.ReadOnly); defer db.close(); try db.exec("BEGIN", .{}); const fd = c.open(scratch, .{ .ACCMODE = .RDWR, .CREAT = true, .EXCL = true }, @as(c.mode_t, 0o600)); if (fd < 0) return error.CreateFailed; defer _ = c.close(fd); var writer = try Packer.init(fd); defer writer.deinit(); for (queries, 1..) |query, tag| { const stmt = try db.prepare(query); defer stmt.deinit(); while (try stmt.step()) { const row: zqlite.Row = .{ .stmt = stmt }; if (row.columnType(0) != .text or row.columnType(1) != .blob) return error.SourceType; const key = row.text(0); if (key.len >= max_key) return error.SourceBounds; var tagged: [max_key]u8 = undefined; tagged[0] = @intCast(tag); @memcpy(tagged[1..][0..key.len], key); try writer.add(tagged[0 .. key.len + 1], row.blob(1)); } } try writer.finish(side); return writer.stats;}
export fn typeahead_compact_pack(source: [*:0]const u8, side: [*:0]const u8, scratch: [*:0]const u8, stats: *Stats) ?[*:0]const u8 { stats.* = pack(source, side, scratch) catch |err| return @errorName(err); return null;}
fn verify(source: [*:0]const u8, side: [*:0]const u8, digest: [*:0]const u8) !u64 { const map = try @import("index/flat_prefix.zig").Map.openFile(a, std.mem.span(side), std.mem.span(digest)); defer map.close(); const db = try zqlite.open(source, zqlite.OpenFlags.ReadOnly); defer db.close(); try db.exec("BEGIN", .{}); const actors = try db.prepare(queries[0]); defer actors.deinit(); const prefixes = try db.prepare(queries[1]); defer prefixes.deinit(); const statements = [_]zqlite.Stmt{ actors, prefixes }; var tag: usize = 0; var count: u64 = 0; var buffer = try a.alloc(u8, page_size); defer a.free(buffer); var key: [max_key]u8 = undefined; var key_len: usize = 0; for (0..map.pages) |i| { const root_pos = map.records + try get(u32, map.bytes, 80 + 4 * i); const root_len = try get(u16, map.bytes, root_pos); const start = map.page_data + try get(u64, map.bytes, root_pos + 2 + root_len); const end = if (i + 1 < map.pages) blk: { const next = map.records + try get(u32, map.bytes, 84 + 4 * i); break :blk map.page_data + try get(u64, map.bytes, next + 2 + try get(u16, map.bytes, next)); } else map.file_size; if (end - start > buffer.len) buffer = try a.realloc(buffer, end - start); const page = buffer[0 .. end - start]; try readAll(map.fd.?, page, start); const entries = try get(u32, page, 0); const key_end = try get(u32, page, 4); const used = try get(u32, page, 8); var pos: usize = 16 + 2 * ((entries + 15) / 16); for (0..entries) |j| { if (j % 16 == 0) { key_len = 0; if (try get(u16, page, 16 + 2 * (j / 16)) != pos) return error.InvalidRestart; } const shared = try readVarint(page[0..key_end], &pos); const suffix = try readVarint(page[0..key_end], &pos); const posting = try get(u16, page[0..key_end], pos); pos += 2; if (shared > key_len or shared + suffix > max_key or pos > key_end or suffix > key_end - pos) return error.InvalidKey; @memcpy(key[shared..][0..suffix], page[pos..][0..suffix]); key_len = shared + suffix; pos += suffix; if (j == 0 and !std.mem.eql(u8, key[0..key_len], map.bytes[root_pos + 2 ..][0..root_len])) return error.RootMismatch; if (posting < key_end or posting > used or used - posting < 4) return error.InvalidPosting; const size = try get(u32, page, posting); if (size > used - posting - 4) return error.InvalidPosting; while (tag < 2) { if (try statements[tag].step()) break; tag += 1; } if (tag == 2) return error.ExtraEntry; const row: zqlite.Row = .{ .stmt = statements[tag] }; if (row.columnType(0) != .text or row.columnType(1) != .blob) return error.SourceType; if (key_len == 0 or key[0] != tag + 1 or !std.mem.eql(u8, key[1..key_len], row.text(0)) or !std.mem.eql(u8, page[posting + 4 ..][0..size], row.blob(1))) return error.SourceMismatch; count += 1; } if (pos != key_end) return error.TrailingKeys; } while (tag < 2) : (tag += 1) { if (try statements[tag].step()) return error.MissingEntry; } return count;}
export fn typeahead_compact_verify(source: [*:0]const u8, side: [*:0]const u8, digest: [*:0]const u8, stats: *Stats) ?[*:0]const u8 { stats.verified_keys = verify(source, side, digest) catch |err| return @errorName(err); return null;}