feat(readers): implement readImageFile

readImageFile passes the file data as an ArrayBuffer to a web worker in the transfer list. Inside
the web worker, the file's contents are mounted to the Emscripten filesystem with the WORKERFS as a
Blob. The generated Emscripten modules are no longer UMD modules to permit proper loading in the web
worker.

BREAKING CHANGE: Emscripten modules no longer wrapped as UMD modules.

Author: thewtex

src/EmscriptenModule/itkJSImageIOPost.js

@@ -40,6 +40,31 @@ Module['unmountContainingDirectory'] = function (filePath) {
   FS.unmount(containingDir)
 }
 
-// UMD module code
-return Module
-}))
+/** Mount file blobs into the Emscripten filesystem. The blobs argument should be an
+ * array of { name: 'filename', data: blob } objects. */
+Module['mountBlobs'] = function (mountpoint, blobs) {
+  if (! ENVIRONMENT_IS_WORKER) {
+    return
+  }
+
+  var currentDir = '/'
+  var splitMountpoint = mountpoint.split('/')
+
+  for (var ii = 1; ii < splitMountpoint.length; ++ii) {
+    currentDir += splitMountpoint[ii]
+    if (!FS.analyzePath(currentDir).exists) {
+      FS.mkdir(currentDir)
+    }
+    currentDir += '/'
+  }
+
+  FS.mount(WORKERFS, {blobs: blobs}, mountpoint)
+}
+
+Module['unmountBlobs'] = function (mountpoint) {
+  if (! ENVIRONMENT_IS_WORKER) {
+    return
+  }
+
+  FS.unmount(mountpoint)
+}

src/EmscriptenModule/itkJSImageIOPre.js

@@ -1,23 +1 @@
-// Export UMD wrapper function for different module loaders.
-(function(root, factory) {
-  // AMD.
-  if(typeof(define) == 'function' && define.amd) {
-    define([], factory)
-  }
-  // Node.js style CommonJS.
-  else if(typeof(module) == 'object' && module.exports) {
-    module.exports = factory()
-  }
-  else {
-    root.Module = factory()
-  }
-
-// Define wrapper function
-}(this, function() {
-  var Module = {}
-  //Module['print'] = console.log
-  //Module['printErr'] = console.warn
-  //Module['print'] = (typeof(console !== "undefined") ? (function(x) { console.log(x) }) : (function(x) {}))
-  //Module['printErr'] = (typeof(console !== "undefined") ? (function(x) { console.warn(x) }) : (function(x) {}))
-
-  // Begin emscripten-generated asm.js code.
+var Module = {}

src/WebWorkers/ImageIOWorker.js

@@ -1,18 +1,58 @@
 const registerPromiseWorker = require('promise-worker-transferable/register')
 
-// const loadEmscriptenModule = require('./itkloadEmscriptenModule.js')
 const ImageType = require('../itkImageType.js')
 const Image = require('../itkImage.js')
 
+const mimeToIO = require('../itkMimeToIO.js')
+const getFileExtension = require('../itkgetFileExtension.js')
+const extensionToIO = require('../itkExtensionToIO.js')
+const readImageEmscriptenFSFile = require('../itkreadImageEmscriptenFSFile.js')
+
+// todo: How to make this configurable?
+const config = require('../itkConfig.js')
+
+// To cache loaded io modules
+let ioToModule = {}
+
+/**
+ * input is an object with keys:
+ *    name: fileNameString
+ *    type: mimeTypeString
+ *    buffer: fileContentsArrayBuffer
+ **/
 registerPromiseWorker(function (input, withTransferList) {
-  console.log('received:')
-  console.log(input)
-  // const modulePath = path.join(config.imageIOsPath, 'itkPNGImageIOJSBinding.js')
-  // const Module = loadEmscriptenModule(modulePath)
-  // const image = readImageEmscriptenFSFile(Module, filePath)
-  // resolve(image)
-  let imageType = new ImageType(3)
-  let image = new Image(imageType)
-  return withTransferList(image, [image.buffer])
+  const extension = getFileExtension(input.name)
+
+  let io = null
+  if (mimeToIO.hasOwnProperty(input.type)) {
+    io = mimeToIO[input.type]
+  } else if (extensionToIO.hasOwnProperty(extension)) {
+    io = extensionToIO[extension]
+  } else {
+    // todo: Iterate through available IO's and have them run
+    // .CanReadFile(filePath)
+  }
+  if (io === null) {
+    return Error('Could not find IO for: ' + input.name)
+  }
+
+  let ioModule = null
+  if (io in ioToModule) {
+    ioModule = ioToModule[io]
+  } else {
+    const modulePath = config.imageIOsPath + '/' + io + '.js'
+    importScripts(modulePath)
+    ioToModule[io] = Module
+    ioModule = Module
+  }
+
+  const blob = new Blob([input.buffer])
+  const blobs = [{ name: input.name, data: blob }]
+  const mountpoint = '/work'
+  ioModule.mountBlobs(mountpoint, blobs)
+  const filePath = mountpoint + '/' + input.name
+  const image = readImageEmscriptenFSFile(ioModule, filePath)
+  ioModule.unmountBlobs(mountpoint)
+
+  return withTransferList(image, [image.buffer.buffer])
 })
-console.log('in the web worker')

src/itkreadImageLocalFile.js

@@ -25,10 +25,10 @@ const readImageLocalFile = (filePath) => {
         // todo: Iterate through available IO's and have them run
         // .CanReadFile(filePath)
       }
-
       if (io === null) {
         reject(Error('Could not find IO for: ' + filePath))
       }
+
       const modulePath = path.join(config.imageIOsPath, io)
       const Module = loadEmscriptenModule(modulePath)
       Module.mountContainingDirectory(filePath)

test/Browser/itkreadImageFileTest.js

@@ -2,6 +2,9 @@ const test = require('tape')
 
 const readImageFile = require('itkreadImageFile.js')
 
+const IntTypes = require('itkIntTypes.js')
+const PixelTypes = require('itkPixelTypes.js')
+
 const cthead1SmallBase64DataURI = 'data:image/png;base64,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'
 const byteString = window.atob(cthead1SmallBase64DataURI.split(',')[1])
 const mimeString = cthead1SmallBase64DataURI.split(',')[0].split(':')[1].split(';')[0]
@@ -14,7 +17,23 @@ const cthead1SmallFile = new window.File([cthead1SmallBlob], 'cthead1Small.png')
 
 test('readImageFile reads a File', t => {
   return readImageFile(cthead1SmallFile).then(function (image) {
-    t.is(image.imageType.dimension, 3, 'dimension is 3')
+    t.is(image.imageType.dimension, 2, 'dimension')
+    t.is(image.imageType.componentType, IntTypes.UInt8, 'componentType')
+    t.is(image.imageType.pixelType, PixelTypes.Scalar, 'pixelType')
+    t.is(image.imageType.components, 1, 'components')
+    t.is(image.origin[0], 0.0, 'origin[0]')
+    t.is(image.origin[1], 0.0, 'origin[1]')
+    t.is(image.spacing[0], 1.0, 'spacing[0]')
+    t.is(image.spacing[1], 1.0, 'spacing[1]')
+    t.is(image.direction, 'aoeu')
+    t.is(image.direction.getElement(0, 0), 1.0, 'direction (0, 0)')
+    t.is(image.direction.getElement(0, 1), 0.0, 'direction (0, 1)')
+    t.is(image.direction.getElement(1, 0), 0.0, 'direction (1, 0)')
+    t.is(image.direction.getElement(1, 1), 1.0, 'direction (1, 1)')
+    t.is(image.size[0], 32, 'size[0]')
+    t.is(image.size[1], 32, 'size[1]')
+    t.is(image.buffer.length, 1024, 'buffer.length')
+    t.is(image.buffer[512], 1024, 'buffer[512]')
     t.end()
   })
 })