support other SQLite wrappers, and various hooks needed by grist-static (#516)

app/common/gristUrls.ts

@@ -198,7 +198,8 @@ export function encodeUrl(gristConfig: Partial<GristLoadConfig>,
                           options: {
                             // make an api url - warning: just barely works, and
                             // only for documents
-                            api?: boolean
+                            api?: boolean,
+                            tweaks?: UrlTweaks,
                           } = {}): string {
   const url = new URL(baseLocation.href);
   const parts = ['/'];
@@ -269,8 +270,10 @@ export function encodeUrl(gristConfig: Partial<GristLoadConfig>,
     }
   }
   const queryStr = encodeQueryParams(queryParams);
+
   url.pathname = parts.join('');
   url.search = queryStr;
+
   if (state.hash) {
     // Project tests use hashes, so only set hash if there is an anchor.
     url.hash = hashParts.join('.');
@@ -285,13 +288,23 @@ export function encodeUrl(gristConfig: Partial<GristLoadConfig>,
   } else {
     url.hash = '';
   }
+  options.tweaks?.postEncode?.({
+    url,
+    parts,
+    state,
+    baseLocation,
+  });
   return url.href;
 }
 
 /**
  * Parse a URL location into an IGristUrlState object. See encodeUrl() documentation.
  */
-export function decodeUrl(gristConfig: Partial<GristLoadConfig>, location: Location | URL): IGristUrlState {
+export function decodeUrl(gristConfig: Partial<GristLoadConfig>, location: Location | URL, options?: {
+  tweaks?: UrlTweaks,
+}): IGristUrlState {
+  location = new URL(location.href);  // Make sure location is a URL.
+  options?.tweaks?.preDecode?.({ url: location });
   const parts = location.pathname.slice(1).split('/');
   const map = new Map<string, string>();
   for (let i = 0; i < parts.length; i += 2) {
@@ -871,3 +884,28 @@ export function getSlugIfNeeded(doc: {id: string, urlId: string|null, name: stri
   if (!shouldIncludeSlug(doc)) { return; }
   return nameToSlug(doc.name);
 }
+
+/**
+ * It is possible we want to remap Grist URLs in some way - specifically,
+ * grist-static does this. We allow for a hook that is called after
+ * encoding state as a URL, and a hook that is called before decoding
+ * state from a URL.
+ */
+export interface UrlTweaks {
+  /**
+   * Tweak an encoded URL. Operates on the URL directly, in place.
+   */
+  postEncode?(options: {
+    url: URL,
+    parts: string[],
+    state: IGristUrlState,
+    baseLocation: Location | URL,
+  }): void;
+
+  /**
+   * Tweak a URL prior to decoding it. Operates on the URL directly, in place.
+   */
+  preDecode?(options: {
+    url: URL,
+  }): void;
+}

app/common/marshal.ts

@@ -33,6 +33,13 @@ import * as util from 'util';
 export interface MarshalOptions {
   stringToBuffer?: boolean;
   version?: number;
+
+  // True if we want keys in dicts to be buffers.
+  // It is convenient to have some freedom here to simplify implementation
+  // of marshaling for some SQLite wrappers. This flag was initially
+  // introduced for a fork of Grist using better-sqlite3, and I don't
+  // remember exactly what the issues were.
+  keysAreBuffers?: boolean;
 }
 
 export interface UnmarshalOptions {
@@ -129,11 +136,13 @@ export class Marshaller {
   private _memBuf: MemBuffer;
   private readonly _floatCode: number;
   private readonly _stringCode: number;
+  private readonly _keysAreBuffers: boolean;
 
   constructor(options?: MarshalOptions) {
     this._memBuf = new MemBuffer(undefined);
     this._floatCode = options && options.version && options.version >= 2 ? marshalCodes.BFLOAT : marshalCodes.FLOAT;
     this._stringCode = options && options.stringToBuffer ? marshalCodes.STRING : marshalCodes.UNICODE;
+    this._keysAreBuffers = Boolean(options?.keysAreBuffers);
   }
 
   public dump(): Uint8Array {
@@ -261,7 +270,7 @@ export class Marshaller {
     const keys = Object.keys(obj);
     keys.sort();
     for (const key of keys) {
-      this.marshal(key);
+      this.marshal(this._keysAreBuffers ? Buffer.from(key) : key);
       this.marshal(obj[key]);
     }
     this._memBuf.writeUint8(marshalCodes.NULL);