exif() returns every EXIF tag in the file (closes #156)

`photo.exif()` now returns every EXIF tag in the file, as the owner ruled, typed `ExifTags`: each tag keyed by name with `exifreader`'s `id`, `value`, `description` and `computed`. A tag with no name is keyed `undefined-` plus its number, and the embedded thumbnail's tags sit under `Thumbnail`. The thirteen typed methods stay, with the same names and types; each now picks its field from `exif()`'s tags. GPS latitude and longitude are worked out from the GPS tags and their reference tags, and a position with no reference tags gives neither. `backup-metadata --exif` output is unchanged.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

src/library/read.ts

@@ -13,14 +13,19 @@
 //
 // A `Photo` also fetches its own bytes: `original()`, `thumbnail()`,
 // `download()`, `content()`, `exif()` and the methods that each return one
-// field of `exif()` go through the on-disk content cache (issue #46), and are
+// EXIF field go through the on-disk content cache (issue #46), and are
 // the one place in this module that may touch the network. A library opened
 // without a content source leaves that cache absent, and those methods then
 // throw. `savePath` and `isLocal` look only at the disk and need no cache.
 
 import { readFile } from "node:fs/promises";
 
-import { readPhotoExif, type PhotoExif } from "../exif.js";
+import {
+    readAllExifTags,
+    readPhotoExif,
+    type ExifTags,
+    type PhotoExif,
+} from "../exif.js";
 import type { CollectionType, EnteFile, FileType } from "../model/types.js";
 import type { ContentOptions, ContentResult, PhotoContent } from "./content.js";
 import type { AlbumRecord, PhotoRecord, DerivedRecords } from "./records.js";
@@ -156,74 +161,75 @@ export class Photo implements PhotoExifMethods {
         return readFile(path);
     }
 
-    // The common EXIF fields of the original, read from `content()`, so this
-    // may download it. EXIF is read from any image format exifreader reads,
-    // JPEG and HEIC/HEIF among them; any other file gives `{}`, and a video
-    // gives it without fetching anything. Like the other content methods, it
-    // throws when there is no content cache, video or not.
-    async exif(opts?: ContentOptions): Promise<PhotoExif> {
+    // Every EXIF tag of the original, keyed by name (see `ExifTags`), read
+    // from `content()`, so this may download it. EXIF is read from any image
+    // format exifreader reads, JPEG and HEIC/HEIF among them; any other file
+    // gives `{}`, and a video gives it without fetching anything. Like the
+    // other content methods, it throws when there is no content cache, video
+    // or not.
+    async exif(opts?: ContentOptions): Promise<ExifTags> {
         this.cacheOrThrow();
         if (this.rec.fileType === "video") return {};
-        return readPhotoExif(await this.content(opts));
+        return readAllExifTags(await this.content(opts));
     }
 
-    // One field of `exif()` each, named and typed as in `PhotoExif`, and
-    // undefined when the file lacks it. Each call runs `exif()`, which reads
-    // the original again.
+    // One field each, named and typed as in `PhotoExif`, picked from the tags
+    // `exif()` returns, and undefined when the file lacks it. Each call runs
+    // `exif()`, which reads the original again.
     async make(opts?: ContentOptions): Promise<PhotoExif["make"]> {
-        return (await this.exif(opts)).make;
+        return readPhotoExif(await this.exif(opts)).make;
     }
     async model(opts?: ContentOptions): Promise<PhotoExif["model"]> {
-        return (await this.exif(opts)).model;
+        return readPhotoExif(await this.exif(opts)).model;
     }
     async lensModel(opts?: ContentOptions): Promise<PhotoExif["lensModel"]> {
-        return (await this.exif(opts)).lensModel;
+        return readPhotoExif(await this.exif(opts)).lensModel;
     }
     async dateTimeOriginal(
         opts?: ContentOptions,
     ): Promise<PhotoExif["dateTimeOriginal"]> {
-        return (await this.exif(opts)).dateTimeOriginal;
+        return readPhotoExif(await this.exif(opts)).dateTimeOriginal;
     }
     async offsetTimeOriginal(
         opts?: ContentOptions,
     ): Promise<PhotoExif["offsetTimeOriginal"]> {
-        return (await this.exif(opts)).offsetTimeOriginal;
+        return readPhotoExif(await this.exif(opts)).offsetTimeOriginal;
     }
     async exposureTime(
         opts?: ContentOptions,
     ): Promise<PhotoExif["exposureTime"]> {
-        return (await this.exif(opts)).exposureTime;
+        return readPhotoExif(await this.exif(opts)).exposureTime;
     }
     async fNumber(opts?: ContentOptions): Promise<PhotoExif["fNumber"]> {
-        return (await this.exif(opts)).fNumber;
+        return readPhotoExif(await this.exif(opts)).fNumber;
     }
     async iso(opts?: ContentOptions): Promise<PhotoExif["iso"]> {
-        return (await this.exif(opts)).iso;
+        return readPhotoExif(await this.exif(opts)).iso;
     }
     async focalLength(
         opts?: ContentOptions,
     ): Promise<PhotoExif["focalLength"]> {
-        return (await this.exif(opts)).focalLength;
+        return readPhotoExif(await this.exif(opts)).focalLength;
     }
     async orientation(
         opts?: ContentOptions,
     ): Promise<PhotoExif["orientation"]> {
-        return (await this.exif(opts)).orientation;
+        return readPhotoExif(await this.exif(opts)).orientation;
     }
     async gpsLatitude(
         opts?: ContentOptions,
     ): Promise<PhotoExif["gpsLatitude"]> {
-        return (await this.exif(opts)).gpsLatitude;
+        return readPhotoExif(await this.exif(opts)).gpsLatitude;
     }
     async gpsLongitude(
         opts?: ContentOptions,
     ): Promise<PhotoExif["gpsLongitude"]> {
-        return (await this.exif(opts)).gpsLongitude;
+        return readPhotoExif(await this.exif(opts)).gpsLongitude;
     }
     async gpsAltitude(
         opts?: ContentOptions,
     ): Promise<PhotoExif["gpsAltitude"]> {
-        return (await this.exif(opts)).gpsAltitude;
+        return readPhotoExif(await this.exif(opts)).gpsAltitude;
     }
 
     private cacheOrThrow(): PhotoContent {