feat(fetcher): first step at optimization

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@web3-storage/blob-fetcher",
-  "version": "2.4.3",
+  "version": "2.4.4-rc.0",
   "description": "A blob fetcher that batches requests and reads multipart byterange responses.",
   "main": "src/index.js",
   "type": "module",
@@ -50,19 +50,24 @@
     "./locator/indexing-service": {
       "import": "./src/locator/indexing-service/index.js",
       "types": "./dist/src/locator/indexing-service/index.d.ts"
+    },
+    "./tracing/tracing": {
+      "import": "./src/tracing/tracing.js",
+      "types": "./dist/src/tracing/tracing.d.ts"
     }
   },
   "dependencies": {
     "@cloudflare/workers-types": "^4.20241022.0",
     "@ipld/dag-ucan": "^3.4.0",
+    "@opentelemetry/api": "^1.9.0",
     "@storacha/indexing-service-client": "^2.0.0",
     "@ucanto/interface": "^10.0.1",
     "@web3-storage/blob-index": "^1.0.2",
     "@web3-storage/content-claims": "^5.1.0",
     "multiformats": "^13.1.0",
-    "multipart-byte-range": "^3.0.1",
     "p-defer": "^4.0.1",
     "p-queue": "^8.0.1",
+    "uint8arraylist": "^2.4.8",
     "zod": "^3.23.8"
   },
   "devDependencies": {

src/api.ts

@@ -1,11 +1,70 @@
 import { ByteView, MultihashDigest } from 'multiformats'
 import { Failure, Result, URI, DID } from '@ucanto/interface'
-import { Range } from 'multipart-byte-range'
 import { QueryError } from '@storacha/indexing-service-client/api'
 
 export { ByteView, MultihashDigest } from 'multiformats'
 export { Failure, Result, URI, DID, Principal } from '@ucanto/interface'
-export { Range, SuffixRange, AbsoluteRange } from 'multipart-byte-range'
+
+/**
+ * An absolute byte range to extract - always an array of two values
+ * corresponding to the first and last bytes (both inclusive). e.g.
+ * 
+ * ```
+ * [100, 200]
+ * ```
+ */
+export type AbsoluteRange = [first: number, last: number]
+
+/**
+ * A suffix byte range - always an array of one value corresponding to the
+ * first byte to start extraction from (inclusive). e.g.
+ * 
+ * ```
+ * [900]
+ * ```
+ * 
+ * If it is unknown how large a resource is, the last `n` bytes
+ * can be requested by specifying a negative value:
+ * 
+ * ```
+ * [-100]
+ * ```
+ */
+export type SuffixRange = [first: number]
+
+/**
+ * Byte range to extract - an array of one or two values corresponding to the
+ * first and last bytes (both inclusive). e.g.
+ * 
+ * ```
+ * [100, 200]
+ * ```
+ * 
+ * Omitting the second value requests all remaining bytes of the resource. e.g.
+ * 
+ * ```
+ * [900]
+ * ```
+ * 
+ * Alternatively, if it's unknown how large a resource is, the last `n` bytes
+ * can be requested by specifying a negative value:
+ * 
+ * ```
+ * [-100]
+ * ```
+ */
+export type Range = AbsoluteRange | SuffixRange
+
+export type ByteGetter = (range: AbsoluteRange) => Promise<ReadableStream<Uint8Array>>
+
+export interface EncoderOptions {
+  /** Mime type of each part. */
+  contentType?: string
+  /** Total size of the object in bytes. */
+  totalSize?: number
+  /** Stream queuing strategy. */
+  strategy?: QueuingStrategy<Uint8Array>
+}
 
 export interface Abortable {
   signal: AbortSignal