Clear storage info (#52)

* Add storageInfo opt to drive.clear()

* (failing test) Add storageInfo test

* Rm test

* Add readme note on storageInfo opt

Author: HDegroote

README.md

@@ -135,10 +135,12 @@ Returns the entry at `path` in the drive. It looks like this:
 
 Deletes the file at `path` from the drive.
 
-#### `await drive.clear(path)`
+#### `await drive.clear(path, [options])`
 
 Deletes the blob from storage to free up space, but the file structure reference is kept.
 
+If `storageInfo = true` is set, an estimate of the amount of bytes freed will be returned (default `false`).
+
 #### `await drive.symlink(path, linkname)`
 
 Creates an entry in drive at `path` that points to the entry at `linkname`.

index.js

@@ -190,12 +190,22 @@ module.exports = class Hyperdrive extends ReadyResource {
     return this.files.del(normalizePath(name))
   }
 
-  async clear (name) {
+  async clear (name, { storageInfo = false } = {}) {
     const node = await this.entry(name)
     if (node === null) return
 
+    const infoBefore = storageInfo
+      ? await this.blobs.core.info({ storage: true })
+      : null
+
     await this.getBlobs()
     await this.blobs.clear(node.value.blob)
+
+    if (infoBefore) {
+      const infoAfter = await this.blobs.core.info({ storage: true })
+      const bytesCleared = infoBefore.storage.blocks - infoAfter.storage.blocks
+      return bytesCleared
+    }
   }
 
   async symlink (name, dst, { metadata = null } = {}) {

test.js

@@ -749,7 +749,8 @@ test('drive.clear(path)', async (t) => {
   const initContent = await drive.blobs.get(entry.value.blob, { wait: false })
   t.alike(initContent, b4a.from('hello world'))
 
-  await drive.clear('/loc')
+  const res = await drive.clear('/loc')
+  t.is(res, undefined)
 
   // Entry still exists (so file not deleted)
   const nowEntry = await drive.entry('/loc')