fix: always read Picasa content from cache

src/input/picasa.js

@@ -10,34 +10,32 @@ const path = require('path')
 
 class Picasa {
   constructor () {
+    // memory cache of all Picasa files read so far
     this.folders = {}
   }
   album (dir) {
-    const entry = loadPicasa(dir)
+    const entry = this.folderMetadata(dir)
     // album metadata is stored in a section called [Picasa]
     return entry.Picasa || null
   }
   file (filepath) {
     const dir = path.dirname(filepath)
-    if (!this.folders[dir]) {
-      this.folders[dir] = loadPicasa(dir)
-    }
+    const entry = this.folderMetadata(dir)
     // file metadata is stored in a section called [FileName.ext]
-    const entry = this.folders[dir]
     const filename = path.basename(filepath)
     const fileParts = filename.split('.')
     return getIniValue(entry, fileParts)
   }
-}
-
-function loadPicasa (dirname) {
-  const inipath = path.join(dirname, 'picasa.ini')
-  const content = loadIfExists(inipath)
-  if (!content) {
-    // return an empty hash, as if the picasa.ini file existed but was empty
-    return {}
-  } else {
-    return ini.parse(content)
+  folderMetadata (dirname) {
+    // try reading from cache first
+    if (this.folders[dirname]) {
+      return this.folders[dirname]
+    }
+    // otherwise try to read the file from disk
+    const inipath = path.join(dirname, 'picasa.ini')
+    const content = loadIfExists(inipath)
+    this.folders[dirname] = content ? ini.parse(content) : {}
+    return this.folders[dirname]
   }
 }
 

test/input/picasa.spec.js

@@ -1,3 +1,5 @@
+const fs = require('fs')
+const sinon = require('sinon')
 const should = require('should/as-function')
 const Picasa = require('../../src/input/picasa.js')
 
@@ -38,6 +40,14 @@ describe('Picasa', function () {
     const meta = picasa.album('holidays')
     should(meta).eql(null)
   })
+  it('returns <null> if the Picasa file is invalid', function () {
+    mock({
+      'holidays/picasa.ini': '[[invalid'
+    })
+    const picasa = new Picasa()
+    const meta = picasa.album('holidays')
+    should(meta).eql(null)
+  })
   it('returns raw file metadata as read from the INI file', function () {
     mock({
       'holidays/picasa.ini': PICASA_INI
@@ -68,4 +78,16 @@ describe('Picasa', function () {
     const meta = picasa.file('holidays/IMG_0002.jpg')
     should(meta).eql(null)
   })
+  it('only reads the file from disk once', function () {
+    mock({
+      'holidays/picasa.ini': PICASA_INI
+    })
+    sinon.spy(fs, 'readFileSync')
+    const picasa = new Picasa()
+    picasa.album('holidays')
+    picasa.album('holidays')
+    picasa.file('holidays/IMG_0001.jpg')
+    picasa.file('holidays/IMG_0002.jpg')
+    should(fs.readFileSync.callCount).eql(1)
+  })
 })