feat: add identity blockstore (#298)

Add a blockstore implementation that supports identity CIDs.

Author: achingbrain

packages/blockstore-core/README.md

@@ -74,6 +74,21 @@ const store = new TieredBlockstore([
 ])
 ```
 
+## Example - IdentityBlockstore
+
+An identity blockstore is one that deals exclusively in Identity CIDs - this is a special CID with the codec [0x00](https://github.com/multiformats/multicodec/blob/d06fc6194710e8909bac64273c43f16b56ca4c34/table.csv#L2) where the multihash digest is the data that makes up the block.
+
+```TypeScript
+import { IdentityBlockstore } from 'blockstore-core/identity'
+import { CID } from 'multiformats/cid'
+
+const blockstore = new IdentityBlockstore()
+
+blockstore.has(CID.parse('QmFoo')) // false
+
+blockstore.has(CID.parse('bafkqac3imvwgy3zao5xxe3de')) // true
+```
+
 # Install
 
 ```console

packages/blockstore-core/package.json

@@ -63,6 +63,10 @@
       "types": "./dist/src/errors.d.ts",
       "import": "./dist/src/errors.js"
     },
+    "./identity": {
+      "types": "./dist/src/identity.d.ts",
+      "import": "./dist/src/identity.js"
+    },
     "./memory": {
       "types": "./dist/src/memory.d.ts",
       "import": "./dist/src/memory.js"

packages/blockstore-core/src/base.ts

@@ -31,8 +31,8 @@ export class BaseBlockstore implements Blockstore {
     }
   }
 
-  async delete (key: CID, options?: AbortOptions): Promise<void> {
-    await Promise.reject(new Error('.delete is not implemented'))
+  delete (key: CID, options?: AbortOptions): Await<void> {
+    return Promise.reject(new Error('.delete is not implemented'))
   }
 
   async * deleteMany (source: AwaitIterable<CID>, options?: AbortOptions): AwaitIterable<CID> {

packages/blockstore-core/src/identity.ts

@@ -0,0 +1,34 @@
+import { BaseBlockstore } from './base.js'
+import * as Errors from './errors.js'
+import type { Pair } from 'interface-blockstore'
+import type { Await, AwaitIterable } from 'interface-store'
+import type { CID } from 'multiformats/cid'
+
+// https://github.com/multiformats/multicodec/blob/d06fc6194710e8909bac64273c43f16b56ca4c34/table.csv#L2
+const IDENTITY_CODEC = 0x00
+
+export class IdentityBlockstore extends BaseBlockstore {
+  put (key: CID): CID {
+    return key
+  }
+
+  get (key: CID): Await<Uint8Array> {
+    if (key.code === IDENTITY_CODEC) {
+      return key.multihash.digest
+    }
+
+    throw Errors.notFoundError()
+  }
+
+  has (key: CID): boolean {
+    return key.code === IDENTITY_CODEC
+  }
+
+  delete (): void {
+
+  }
+
+  * getAll (): AwaitIterable<Pair> {
+
+  }
+}

packages/blockstore-core/src/index.ts

@@ -65,6 +65,21 @@
  *   // ...etc
  * ])
  * ```
+ *
+ * @example IdentityBlockstore
+ *
+ * An identity blockstore is one that deals exclusively in Identity CIDs - this is a special CID with the codec [0x00](https://github.com/multiformats/multicodec/blob/d06fc6194710e8909bac64273c43f16b56ca4c34/table.csv#L2) where the multihash digest is the data that makes up the block.
+ *
+ * ```TypeScript
+ * import { IdentityBlockstore } from 'blockstore-core/identity'
+ * import { CID } from 'multiformats/cid'
+ *
+ * const blockstore = new IdentityBlockstore()
+ *
+ * blockstore.has(CID.parse('QmFoo')) // false
+ *
+ * blockstore.has(CID.parse('bafkqac3imvwgy3zao5xxe3de')) // true
+ * ```
  */
 
 import * as ErrorsImport from './errors.js'

packages/blockstore-core/test/identity.spec.ts

@@ -0,0 +1,59 @@
+/* eslint-env mocha */
+
+import { expect } from 'aegir/chai'
+import drain from 'it-drain'
+import { CID } from 'multiformats/cid'
+import * as raw from 'multiformats/codecs/raw'
+import { identity } from 'multiformats/hashes/identity'
+import { sha256 } from 'multiformats/hashes/sha2'
+import { IdentityBlockstore } from '../src/identity.js'
+import type { Blockstore } from 'interface-blockstore'
+
+describe('identity', () => {
+  let blockstore: Blockstore
+
+  beforeEach(() => {
+    blockstore = new IdentityBlockstore()
+  })
+
+  it('has an identity CID', () => {
+    const block = Uint8Array.from([0, 1, 2, 3, 4])
+    const multihash = identity.digest(block)
+    const cid = CID.createV1(identity.code, multihash)
+
+    expect(blockstore.has(cid)).to.be.true()
+    expect(blockstore.get(cid)).to.equalBytes(block)
+  })
+
+  it('does not have a non-identity CID', async () => {
+    const block = Uint8Array.from([0, 1, 2, 3, 4])
+    const multihash = await sha256.digest(block)
+    const cid = CID.createV1(raw.code, multihash)
+
+    expect(blockstore.has(cid)).to.be.false()
+
+    await blockstore.put(cid, block)
+
+    expect(blockstore.has(cid)).to.be.false()
+  })
+
+  it('cannot delete an identity CID', async () => {
+    const block = Uint8Array.from([0, 1, 2, 3, 4])
+    const multihash = identity.digest(block)
+    const cid = CID.createV1(identity.code, multihash)
+
+    await blockstore.delete(cid)
+
+    expect(blockstore.has(cid)).to.be.true()
+  })
+
+  it('cannot delete many identity CIDs', async () => {
+    const block = Uint8Array.from([0, 1, 2, 3, 4])
+    const multihash = identity.digest(block)
+    const cid = CID.createV1(identity.code, multihash)
+
+    await drain(blockstore.deleteMany([cid]))
+
+    expect(blockstore.has(cid)).to.be.true()
+  })
+})

packages/blockstore-core/typedoc.json

@@ -4,6 +4,7 @@
     "./src/base.ts",
     "./src/black-hole.ts",
     "./src/errors.ts",
+    "./src/identity.ts",
     "./src/memory.ts",
     "./src/tiered.ts"
   ]