fix: do not strip prefixes for MountDatastores (#82)

If you have a mount datastore:

```js
const d = new MountDatastore([{
  datastore: foo,
  prefix: new Key('/bar')
}])
```

`d.put(new Key('/bar/baz'), val)` results in `foo.put(new Key('/baz'), val)`.

This PR changes the default behaviour to `foo.put(new Key('/bar/baz'), val)`.

If you need the old behaviour, use a `KeyTransformDatastore` to strip the prefix - see [stripPrefixDatastore](https://github.com/ipfs/js-datastore-core/blob/master/test/mount.spec.js#L17) in the MountDatastore tests for an example.

BREAKING CHANGE: key prefixes are no longer stripped by MountDatastore

Author: achingbrain

README.md

@@ -29,7 +29,7 @@
   - Keytransform: [`src/keytransform`](src/keytransform.js)
   - Sharding: [`src/sharding`](src/sharding.js)
   - Tiered: [`src/tiered`](src/tirered.js)
-  - Namespace: [`src/tiered`](src/namespace.js)
+  - Namespace: [`src/namespace`](src/namespace.js)
 
 ## Install
 

package.json

@@ -84,7 +84,7 @@
   "homepage": "https://github.com/ipfs/js-datastore-core#readme",
   "devDependencies": {
     "@types/debug": "^4.1.5",
-    "aegir": "^35.0.2",
+    "aegir": "^36.1.3",
     "interface-datastore-tests": "^2.0.3",
     "it-all": "^1.0.4",
     "rimraf": "^3.0.2",

src/keytransform.js

@@ -169,7 +169,33 @@ export class KeyTransformDatastore extends BaseDatastore {
    * @param {Options} [options]
    */
   query (q, options) {
-    return map(this.child.query(q, options), ({ key, value }) => {
+    /** @type {Query} */
+    const query = {
+      ...q
+    }
+
+    query.filters = (query.filters || []).map(filter => {
+      return ({ key, value }) => filter({ key: this.transform.convert(key), value })
+    })
+
+    const { prefix } = q
+    if (prefix != null && prefix !== '/') {
+      delete query.prefix
+      query.filters.push(({ key }) => {
+        return this.transform.invert(key).toString().startsWith(prefix)
+      })
+    }
+
+    if (query.orders) {
+      query.orders = query.orders.map(order => {
+        return (a, b) => order(
+          { key: this.transform.invert(a.key), value: a.value },
+          { key: this.transform.invert(b.key), value: b.value }
+        )
+      })
+    }
+
+    return map(this.child.query(query, options), ({ key, value }) => {
       return {
         key: this.transform.invert(key),
         value
@@ -182,7 +208,32 @@ export class KeyTransformDatastore extends BaseDatastore {
    * @param {Options} [options]
    */
   queryKeys (q, options) {
-    return map(this.child.queryKeys(q, options), key => {
+    const query = {
+      ...q
+    }
+
+    query.filters = (query.filters || []).map(filter => {
+      return (key) => filter(this.transform.convert(key))
+    })
+
+    const { prefix } = q
+    if (prefix != null && prefix !== '/') {
+      delete query.prefix
+      query.filters.push((key) => {
+        return this.transform.invert(key).toString().startsWith(prefix)
+      })
+    }
+
+    if (query.orders) {
+      query.orders = query.orders.map(order => {
+        return (a, b) => order(
+          this.transform.invert(a),
+          this.transform.invert(b)
+        )
+      })
+    }
+
+    return map(this.child.queryKeys(query, options), key => {
       return this.transform.invert(key)
     })
   }

src/mount.js

@@ -2,16 +2,14 @@ import filter from 'it-filter'
 import take from 'it-take'
 import merge from 'it-merge'
 import { BaseDatastore } from './base.js'
-import { KeyTransformDatastore } from './keytransform.js'
 import * as Errors from './errors.js'
 import {
-  sortAll,
-  replaceStartWith
+  sortAll
 } from './utils.js'
-import { Key } from 'interface-datastore/key'
 
 /**
  * @typedef {import('interface-datastore').Datastore} Datastore
+ * @typedef {import('interface-datastore').Key} Key
  * @typedef {import('interface-datastore').Options} Options
  * @typedef {import('interface-datastore').Batch} Batch
  * @typedef {import('interface-datastore').Query} Query
@@ -44,16 +42,14 @@ export class MountDatastore extends BaseDatastore {
    *
    * @private
    * @param {Key} key
-   * @returns {{datastore: Datastore, mountpoint: Key, rest: Key} | undefined}
+   * @returns {{datastore: Datastore, mountpoint: Key} | undefined}
    */
   _lookup (key) {
     for (const mount of this.mounts) {
       if (mount.prefix.toString() === key.toString() || mount.prefix.isAncestorOf(key)) {
-        const s = replaceStartWith(key.toString(), mount.prefix.toString())
         return {
           datastore: mount.datastore,
-          mountpoint: mount.prefix,
-          rest: new Key(s)
+          mountpoint: mount.prefix
         }
       }
     }
@@ -70,7 +66,7 @@ export class MountDatastore extends BaseDatastore {
       throw Errors.dbWriteFailedError(new Error('No datastore mounted for this key'))
     }
 
-    return match.datastore.put(match.rest, value, options)
+    return match.datastore.put(key, value, options)
   }
 
   /**
@@ -82,7 +78,7 @@ export class MountDatastore extends BaseDatastore {
     if (match == null) {
       throw Errors.notFoundError(new Error('No datastore mounted for this key'))
     }
-    return match.datastore.get(match.rest, options)
+    return match.datastore.get(key, options)
   }
 
   /**
@@ -94,7 +90,7 @@ export class MountDatastore extends BaseDatastore {
     if (match == null) {
       return Promise.resolve(false)
     }
-    return match.datastore.has(match.rest, options)
+    return match.datastore.has(key, options)
   }
 
   /**
@@ -107,7 +103,7 @@ export class MountDatastore extends BaseDatastore {
       throw Errors.dbDeleteFailedError(new Error('No datastore mounted for this key'))
     }
 
-    return match.datastore.delete(match.rest, options)
+    return match.datastore.delete(key, options)
   }
 
   async close () {
@@ -137,19 +133,18 @@ export class MountDatastore extends BaseDatastore {
       }
 
       return {
-        batch: batchMounts[m],
-        rest: match.rest
+        batch: batchMounts[m]
       }
     }
 
     return {
       put: (key, value) => {
         const match = lookup(key)
-        match.batch.put(match.rest, value)
+        match.batch.put(key, value)
       },
       delete: (key) => {
         const match = lookup(key)
-        match.batch.delete(match.rest)
+        match.batch.delete(key)
       },
       commit: async (options) => {
         await Promise.all(Object.keys(batchMounts).map(p => batchMounts[p].commit(options)))
@@ -163,22 +158,8 @@ export class MountDatastore extends BaseDatastore {
    */
   query (q, options) {
     const qs = this.mounts.map(m => {
-      const ks = new KeyTransformDatastore(m.datastore, {
-        convert: (key) => {
-          throw new Error('should never be called')
-        },
-        invert: (key) => {
-          return m.prefix.child(key)
-        }
-      })
-
-      let prefix
-      if (q.prefix != null) {
-        prefix = replaceStartWith(q.prefix, m.prefix.toString())
-      }
-
-      return ks.query({
-        prefix: prefix,
+      return m.datastore.query({
+        prefix: q.prefix,
         filters: q.filters
       }, options)
     })
@@ -201,22 +182,8 @@ export class MountDatastore extends BaseDatastore {
    */
   queryKeys (q, options) {
     const qs = this.mounts.map(m => {
-      const ks = new KeyTransformDatastore(m.datastore, {
-        convert: (key) => {
-          throw new Error('should never be called')
-        },
-        invert: (key) => {
-          return m.prefix.child(key)
-        }
-      })
-
-      let prefix
-      if (q.prefix != null) {
-        prefix = replaceStartWith(q.prefix, m.prefix.toString())
-      }
-
-      return ks.queryKeys({
-        prefix: prefix,
+      return m.datastore.queryKeys({
+        prefix: q.prefix,
         filters: q.filters
       }, options)
     })

src/namespace.js

@@ -16,7 +16,6 @@ import { KeyTransformDatastore } from './keytransform.js'
  * For example, if the prefix is `new Key(/hello)` a call
  * to `store.put(new Key('/world'), mydata)` would store the data under
  * `/hello/world`.
- *
  */
 export class NamespaceDatastore extends KeyTransformDatastore {
   /**
@@ -40,33 +39,5 @@ export class NamespaceDatastore extends KeyTransformDatastore {
         return new Key(key.toString().slice(prefix.toString().length), false)
       }
     })
-
-    this.prefix = prefix
-  }
-
-  /**
-   * @param {Query} q
-   * @param {Options} [options]
-   */
-  query (q, options) {
-    if (q.prefix && this.prefix.toString() !== '/') {
-      return super.query(Object.assign({}, q, {
-        prefix: this.prefix.child(new Key(q.prefix)).toString()
-      }))
-    }
-    return super.query(q, options)
-  }
-
-  /**
-   * @param {KeyQuery} q
-   * @param {Options} [options]
-   */
-  queryKeys (q, options) {
-    if (q.prefix && this.prefix.toString() !== '/') {
-      return super.queryKeys(Object.assign({}, q, {
-        prefix: this.prefix.child(new Key(q.prefix)).toString()
-      }))
-    }
-    return super.queryKeys(q, options)
   }
 }

src/sharding.js

@@ -208,57 +208,15 @@ export class ShardingDatastore extends BaseDatastore {
    * @param {Options} [options]
    */
   query (q, options) {
+    /** @type {Query} */
     const tq = {
-      offset: q.offset,
-      limit: q.limit,
-      /** @type {QueryOrder[]} */
-      orders: [],
-      /** @type {QueryFilter[]} */
+      ...q,
       filters: [
         /** @type {QueryFilter} */
-        e => e.key.toString() !== shardKey.toString(),
+        ({ key }) => key.toString() !== shardKey.toString(),
         /** @type {QueryFilter} */
-        e => e.key.toString() !== shardReadmeKey.toString()
-      ]
-    }
-
-    const { prefix } = q
-    if (prefix != null) {
-      tq.filters.push((e) => {
-        return this._invertKey(e.key).toString().startsWith(prefix)
-      })
-    }
-
-    if (q.filters != null) {
-      const filters = q.filters.map(f => {
-        /** @type {QueryFilter} */
-        const filter = ({ key, value }) => {
-          return f({
-            key: this._invertKey(key),
-            value
-          })
-        }
-
-        return filter
-      })
-      tq.filters = tq.filters.concat(filters)
-    }
-
-    if (q.orders != null) {
-      tq.orders = q.orders.map(o => {
-        /** @type {QueryOrder} */
-        const order = (a, b) => {
-          return o({
-            key: this._invertKey(a.key),
-            value: a.value
-          }, {
-            key: this._invertKey(b.key),
-            value: b.value
-          })
-        }
-
-        return order
-      })
+        ({ key }) => key.toString() !== shardReadmeKey.toString()
+      ].concat(q.filters || [])
     }
 
     return this.child.query(tq, options)
@@ -269,46 +227,15 @@ export class ShardingDatastore extends BaseDatastore {
    * @param {Options} [options]
    */
   queryKeys (q, options) {
+    /** @type {KeyQuery} */
     const tq = {
-      offset: q.offset,
-      limit: q.limit,
-      /** @type {KeyQueryOrder[]} */
-      orders: [],
-      /** @type {KeyQueryFilter[]} */
+      ...q,
       filters: [
         /** @type {KeyQueryFilter} */
         key => key.toString() !== shardKey.toString(),
         /** @type {KeyQueryFilter} */
         key => key.toString() !== shardReadmeKey.toString()
-      ]
-    }
-
-    const { prefix } = q
-    if (prefix != null) {
-      tq.filters.push((key) => {
-        return this._invertKey(key).toString().startsWith(prefix)
-      })
-    }
-
-    if (q.filters != null) {
-      const filters = q.filters.map(f => {
-        /** @type {KeyQueryFilter} */
-        const filter = (key) => {
-          return f(this._invertKey(key))
-        }
-
-        return filter
-      })
-      tq.filters = tq.filters.concat(filters)
-    }
-
-    if (q.orders != null) {
-      tq.orders = q.orders.map(o => {
-        /** @type {KeyQueryOrder} */
-        const order = (a, b) => o(this._invertKey(a), this._invertKey(b))
-
-        return order
-      })
+      ].concat(q.filters || [])
     }
 
     return this.child.queryKeys(tq, options)