mirrors/PMTiles
1
0
Fork 0
mirror of https://github.com/protomaps/PMTiles.git synced 2026-02-04 10:51:07 +00:00
Code Issues Packages Projects Releases Wiki Activity

add minimal shim stubs for v2 backwards compatibility

Browse Source
This commit is contained in:
Brandon Liu
2022-10-04 12:25:08 +08:00
parent 9594cd1764
commit 96d7ba7748
2 changed files with 88 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
js/v3.ts
View File

@@ -1,4 +1,5 @@
import { decompressSync } from "fflate";
import v2 from "./v2";
export interface BufferPosition {
buf: Uint8Array;
@@ -159,14 +160,15 @@ enum TileType {
const HEADER_SIZE_BYTES = 122;
export interface Header {
specVersion: number;
rootDirectoryOffset: number;
rootDirectoryLength: number;
jsonMetadataOffset: number;
jsonMetadataLength: number;
leafDirectoryOffset: number;
leafDirectoryLength: number;
leafDirectoryLength?: number;
tileDataOffset: number;
tileDataLength: number;
tileDataLength?: number;
numAddressedTiles: number;
numTileEntries: number;
numTileContents: number;
@@ -301,6 +303,7 @@ export function bytesToHeader(bytes: ArrayBuffer, etag?: string): Header {
throw new Error("Wrong magic number for PMTiles archive");
}
return {
specVersion: 3,
rootDirectoryOffset: Number(v.getBigUint64(3, true)),
rootDirectoryLength: Number(v.getBigUint64(11, true)),
jsonMetadataOffset: Number(v.getBigUint64(19, true)),
@@ -362,6 +365,10 @@ function deserializeIndex(buffer: ArrayBuffer): Entry[] {
return entries;
}
function detectVersion(a: ArrayBuffer): number {
return 3;
}
export class VersionMismatch extends Error {}
export interface Cache {
@@ -387,36 +394,37 @@ async function getHeaderAndRoot(
): Promise<[Header, [string, number, Entry[] | ArrayBuffer]?]> {
let resp = await source.getBytes(0, 16384);
// check spec revision
if (false) {
} else {
const headerData = resp.data.slice(0, HEADER_SIZE_BYTES);
const header = bytesToHeader(headerData, resp.etag);
// optimistically set the root directory
// TODO check root bounds
if (prefetch) {
const rootDirData = resp.data.slice(
header.rootDirectoryOffset,
header.rootDirectoryOffset + header.rootDirectoryLength
);
const dirKey =
source.getKey() +
"|" +
(header.etag || "") +
"|" +
header.rootDirectoryOffset +
"|" +
header.rootDirectoryLength;
const rootDir = deserializeIndex(
tryDecompress(rootDirData, header.internalCompression)
);
return [header, [dirKey, ENTRY_SIZE_BYTES * rootDir.length, rootDir]];
}
return [header, undefined];
// V2 COMPATIBILITY
if (detectVersion(resp.data) < 2) {
return v2.getHeaderAndRoot(resp.data, resp.etag);
}
const headerData = resp.data.slice(0, HEADER_SIZE_BYTES);
const header = bytesToHeader(headerData, resp.etag);
// optimistically set the root directory
// TODO check root bounds
if (prefetch) {
const rootDirData = resp.data.slice(
header.rootDirectoryOffset,
header.rootDirectoryOffset + header.rootDirectoryLength
);
const dirKey =
source.getKey() +
"|" +
(header.etag || "") +
"|" +
header.rootDirectoryOffset +
"|" +
header.rootDirectoryLength;
const rootDir = deserializeIndex(
tryDecompress(rootDirData, header.internalCompression)
);
return [header, [dirKey, ENTRY_SIZE_BYTES * rootDir.length, rootDir]];
}
return [header, undefined];
}
async function getDirectory(
@@ -749,6 +757,11 @@ export class PMTiles {
const tile_id = zxyToTileId(z, x, y);
const header = await this.cache.getHeader(this.source);
// V2 COMPATIBILITY
if (header.specVersion < 3) {
return v2.getZxy(header, this.cache);
}
if (z < header.minZoom || z > header.maxZoom) {
return undefined;
}
@@ -809,6 +822,7 @@ export class PMTiles {
async getMetadataAttempt(): Promise<any> {
const header = await this.cache.getHeader(this.source);
const resp = await this.source.getBytes(
header.jsonMetadataOffset,
header.jsonMetadataLength