feat(read): change hasContent to return {sri, size} (#88)

Fixes #87

BREAKING CHANGE: hasContent now returns an object with `{sri, size}` instead of `sri`. Use `result.sri` anywhere that needed the old return value.

Author: Alexander Plavinski

README.md

@@ -297,9 +297,9 @@ cacache.get.info(cachePath, 'my-thing').then(console.log)
 
 #### <a name="get-hasContent"></a> `> cacache.get.hasContent(cache, integrity) -> Promise`
 
-Looks up a [Subresource Integrity hash](#integrity) in the cache. If content 
-exists for this `integrity`, it will return the specific single integrity hash
-that was found. If no content exists for this integrity, it will return `false`.
+Looks up a [Subresource Integrity hash](#integrity) in the cache. If content
+exists for this `integrity`, it will return an object, with the specific single integrity hash
+that was found in `sri` key, and the size of the found content as `size`. If no content exists for this integrity, it will return `false`.
 
 ##### Fields
 
@@ -316,10 +316,13 @@ cacache.get.hasContent(cachePath, 'sha256-MUSTVERIFY+ALL/THINGS==').then(console
 
 // Output
 {
-  source: 'sha256-MUSTVERIFY+ALL/THINGS==',
-  algorithm: 'sha256',
-  digest: 'MUSTVERIFY+ALL/THINGS==',
-  options: []
+  sri: {
+    source: 'sha256-MUSTVERIFY+ALL/THINGS==',
+    algorithm: 'sha256',
+    digest: 'MUSTVERIFY+ALL/THINGS==',
+    options: []
+  },
+  size: 9001
 }
 
 cacache.get.hasContent(cachePath, 'sha521-NOT+IN/CACHE==').then(console.log)
@@ -397,7 +400,7 @@ for inserted data. Can use any algorithm listed in `crypto.getHashes()` or
 `'omakase'`/`'お任せします'` to pick a random hash algorithm on each insertion. You
 may also use any anagram of `'modnar'` to use this feature.
 
-Currently only supports one algorithm at a time (i.e., an array length of 
+Currently only supports one algorithm at a time (i.e., an array length of
 exactly `1`). Has no effect if `opts.integrity` is present.
 
 ##### `opts.uid`/`opts.gid`

lib/content/read.js

@@ -13,7 +13,8 @@ BB.promisifyAll(fs)
 module.exports = read
 function read (cache, integrity, opts) {
   opts = opts || {}
-  return pickContentSri(cache, integrity).then(sri => {
+  return pickContentSri(cache, integrity).then(content => {
+    const sri = content.sri
     const cpath = contentPath(cache, sri)
     return fs.readFileAsync(cpath, null).then(data => {
       if (typeof opts.size === 'number' && opts.size !== data.length) {
@@ -34,7 +35,8 @@ function readStream (cache, integrity, opts) {
   const stream = new PassThrough()
   pickContentSri(
     cache, integrity
-  ).then(sri => {
+  ).then(content => {
+    const sri = content.sri
     return pipe(
       fs.createReadStream(contentPath(cache, sri)),
       ssri.integrityStream({
@@ -52,34 +54,33 @@ function readStream (cache, integrity, opts) {
 module.exports.hasContent = hasContent
 function hasContent (cache, integrity) {
   if (!integrity) { return BB.resolve(false) }
-  return pickContentSri(cache, integrity, true)
+  return pickContentSri(cache, integrity)
   .catch({code: 'ENOENT'}, () => false)
   .catch({code: 'EPERM'}, err => {
     if (process.platform !== 'win32') {
       throw err
     } else {
       return false
     }
-  }).then(sri => sri || false)
+  }).then(content => {
+    if (!content.sri) return false
+    return ({ sri: content.sri, size: content.stat.size })
+  })
 }
 
 module.exports._pickContentSri = pickContentSri
-function pickContentSri (cache, integrity, checkFs) {
+function pickContentSri (cache, integrity) {
   const sri = ssri.parse(integrity)
   // If `integrity` has multiple entries, pick the first digest
   // with available local data.
   const algo = sri.pickAlgorithm()
   const digests = sri[algo]
   if (digests.length <= 1) {
     const cpath = contentPath(cache, digests[0])
-    if (checkFs) {
-      return fs.lstatAsync(cpath).then(() => digests[0])
-    } else {
-      return BB.resolve(digests[0])
-    }
+    return fs.lstatAsync(cpath).then(stat => ({ sri: digests[0], stat }))
   } else {
     return BB.any(sri[sri.pickAlgorithm()].map(meta => {
-      return pickContentSri(cache, meta, true)
+      return pickContentSri(cache, meta)
     }))
   }
 }

lib/content/rm.js

@@ -8,7 +8,8 @@ const rimraf = BB.promisify(require('rimraf'))
 
 module.exports = rm
 function rm (cache, integrity) {
-  return hasContent(cache, integrity).then(sri => {
+  return hasContent(cache, integrity).then(content => {
+    const sri = content.sri
     if (sri) {
       return rimraf(contentPath(cache, sri))
     }

test/content.read.js

@@ -132,17 +132,18 @@ test('read: errors if content size does not match size option', function (t) {
   )
 })
 
-test('hasContent: returns true when a cache file exists', function (t) {
+test('hasContent: returns { sri, size } when a cache file exists', function (t) {
   const fixture = new Tacks(CacheContent({
     'sha1-deadbeef': ''
   }))
   fixture.create(CACHE)
   return BB.join(
-    read.hasContent(CACHE, 'sha1-deadbeef').then(bool => {
-      t.ok(bool, 'returned true for existing content')
+    read.hasContent(CACHE, 'sha1-deadbeef').then(content => {
+      t.ok(content.sri, 'returned sri for this content')
+      t.equal(content.size, 0, 'returned the right size for this content')
     }),
-    read.hasContent(CACHE, 'sha1-not-there').then(bool => {
-      t.equal(bool, false, 'returned false for missing content')
+    read.hasContent(CACHE, 'sha1-not-there').then(content => {
+      t.equal(content, false, 'returned false for missing content')
     })
   )
 })