Implement (de)serialization and binary encoding

Fixes #9.

index.js

@@ -4,6 +4,7 @@ const compare = require('./lib/compare')
 const describe = require('./lib/describe')
 const diff = require('./lib/diff')
 const format = require('./lib/format')
+const serialize = require('./lib/serialize')
 
 exports.compare = compare.compare
 exports.compareDescriptors = compare.compareDescriptors
@@ -15,3 +16,6 @@ exports.diffDescriptors = diff.diffDescriptors
 
 exports.format = format.format
 exports.formatDescriptor = format.formatDescriptor
+
+exports.serialize = serialize.serialize
+exports.deserialize = serialize.deserialize

lib/complexValues/arguments.js

@@ -15,14 +15,20 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedArgumentsValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('ArgumentsValue')
 exports.tag = tag
 
 class ArgumentsValue extends object.ObjectValue {
   compare (expected) {
     if (expected.isComplex !== true) return UNEQUAL
 
-    // Calling code may decide that Arguments can be compared to Arrays
+    // When used on the left-hand side of a comparison, argument values may be
+    // compared to arrays.
     if (expected.stringTag === 'Array') return AMBIGUOUS
 
     return super.compare(expected)
@@ -31,3 +37,12 @@ class ArgumentsValue extends object.ObjectValue {
 Object.defineProperty(ArgumentsValue.prototype, 'tag', { value: tag })
 
 const DescribedArgumentsValue = object.DescribedMixin(ArgumentsValue)
+
+class DeserializedArgumentsValue extends object.DeserializedMixin(ArgumentsValue) {
+  compare (expected) {
+    // Deserialized argument values may only be compared to argument values.
+    return expected.isComplex === true && expected.stringTag === 'Array'
+      ? UNEQUAL
+      : super.compare(expected)
+  }
+}

lib/complexValues/arrayBuffer.js

@@ -13,6 +13,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedArrayBufferValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('ArrayBufferValue')
 exports.tag = tag
 
@@ -22,3 +27,4 @@ class ArrayBufferValue extends typedArray.TypedArrayValue {}
 Object.defineProperty(ArrayBufferValue.prototype, 'tag', { value: tag })
 
 const DescribedArrayBufferValue = typedArray.DescribedMixin(ArrayBufferValue)
+const DeserializedArrayBufferValue = typedArray.DeserializedMixin(ArrayBufferValue)

lib/complexValues/dataView.js

@@ -12,6 +12,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedDataViewValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('DataViewValue')
 exports.tag = tag
 
@@ -21,3 +26,4 @@ class DataViewValue extends typedArray.TypedArrayValue {}
 Object.defineProperty(DataViewValue.prototype, 'tag', { value: tag })
 
 const DescribedDataViewValue = typedArray.DescribedMixin(DataViewValue)
+const DeserializedDataViewValue = typedArray.DeserializedMixin(DataViewValue)

lib/complexValues/date.js

@@ -8,6 +8,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedDateValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('DateValue')
 exports.tag = tag
 
@@ -26,7 +31,18 @@ class DateValue extends object.ObjectValue {
       }
     })
   }
+
+  serialize () {
+    return [this.value.toISOString(), super.serialize()]
+  }
 }
 Object.defineProperty(DateValue.prototype, 'tag', { value: tag })
 
 const DescribedDateValue = object.DescribedMixin(DateValue)
+
+class DeserializedDateValue extends object.DeserializedMixin(DateValue) {
+  constructor (state, recursor) {
+    super(state[1], recursor)
+    this.value = new Date(state[0])
+  }
+}

lib/complexValues/error.js

@@ -18,6 +18,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedErrorValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('ErrorValue')
 exports.tag = tag
 
@@ -59,6 +64,10 @@ class ErrorValue extends object.ObjectValue {
       }
     })
   }
+
+  serialize () {
+    return [this.name, super.serialize()]
+  }
 }
 Object.defineProperty(ErrorValue.prototype, 'tag', { value: tag })
 
@@ -111,3 +120,10 @@ class DescribedErrorValue extends object.DescribedMixin(ErrorValue) {
     return { size, next }
   }
 }
+
+class DeserializedErrorValue extends object.DeserializedMixin(ErrorValue) {
+  constructor (state, recursor) {
+    super(state[1], recursor)
+    this.name = state[0]
+  }
+}

lib/complexValues/function.js

@@ -1,13 +1,17 @@
 'use strict'
 
 const constants = require('../constants')
+const getStringTag = require('../getStringTag')
 const isEnumerable = require('../isEnumerable')
 const NOOP_RECURSOR = require('../recursorUtils').NOOP_RECURSOR
 const object = require('./object')
 
 const UNEQUAL = constants.UNEQUAL
 const SHALLOW_EQUAL = constants.SHALLOW_EQUAL
 
+// Node.js 4 provides Function, more recent versions use GeneratorFunction
+const generatorsHaveGeneratorTag = getStringTag(function * () {}) === 'GeneratorFunction'
+
 function describe (props) {
   const fn = props.value
   return new DescribedFunctionValue(Object.assign({
@@ -17,6 +21,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedFunctionValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('FunctionValue')
 exports.tag = tag
 
@@ -40,6 +49,10 @@ class FunctionValue extends object.ObjectValue {
       }
     })
   }
+
+  serialize () {
+    return [this.name, generatorsHaveGeneratorTag, super.serialize()]
+  }
 }
 Object.defineProperty(FunctionValue.prototype, 'tag', { value: tag })
 
@@ -85,3 +98,25 @@ class DescribedFunctionValue extends object.DescribedMixin(FunctionValue) {
     return { size, next }
   }
 }
+
+class DeserializedFunctionValue extends object.DeserializedMixin(FunctionValue) {
+  constructor (state, recursor) {
+    super(state[2], recursor)
+    this.name = state[0]
+    this.trustStringTag = state[1]
+  }
+
+  compare (expected) {
+    if (this.tag !== expected.tag) return UNEQUAL
+    if (this.name !== expected.name) return UNEQUAL
+
+    // Assume `stringTag` is either 'Function' or 'GeneratorFunction', and that
+    // it always equals `ctor`. Since Node.js 4 only provides 'Function', even
+    // for generator functions, only compare `stringTag` if the serialized value
+    // legitimately would have been `Function`, and the expected `stringTag` can
+    // reliably be inferred.
+    if (this.trustStringTag && generatorsHaveGeneratorTag && this.stringTag !== expected.stringTag) return UNEQUAL
+
+    return SHALLOW_EQUAL
+  }
+}

lib/complexValues/global.js

@@ -10,6 +10,8 @@ function describe () {
 }
 exports.describe = describe
 
+exports.deserialize = describe
+
 const tag = Symbol('GlobalValue')
 exports.tag = tag
 

lib/complexValues/map.js

@@ -12,6 +12,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedMapValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('MapValue')
 exports.tag = tag
 
@@ -32,6 +37,10 @@ class MapValue extends object.ObjectValue {
       ? UNEQUAL
       : super.compare(expected)
   }
+
+  serialize () {
+    return [this.size, super.serialize()]
+  }
 }
 Object.defineProperty(MapValue.prototype, 'tag', { value: tag })
 
@@ -55,3 +64,10 @@ class DescribedMapValue extends object.DescribedMixin(MapValue) {
     return { size, next }
   }
 }
+
+class DeserializedMapValue extends object.DeserializedMixin(MapValue) {
+  constructor (state, recursor) {
+    super(state[1], recursor)
+    this.size = state[0]
+  }
+}

lib/complexValues/object.js

@@ -22,6 +22,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedObjectValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('ObjectValue')
 exports.tag = tag
 
@@ -47,12 +52,17 @@ class ObjectValue {
   format (gutter, indent, innerIndent) {
     return new ObjectFormatter(this, gutter, indent, innerIndent)
   }
+
+  serialize () {
+    return [this.ctor, this.pointer, this.stringTag, this.unwrapped, this.isArray, this.isIterable, this.isList]
+  }
 }
 Object.defineProperty(ObjectValue.prototype, 'isComplex', { value: true })
 Object.defineProperty(ObjectValue.prototype, 'tag', { value: tag })
 exports.ObjectValue = ObjectValue
 
 const DescribedObjectValue = DescribedMixin(ObjectValue)
+const DeserializedObjectValue = DeserializedMixin(ObjectValue)
 
 function DescribedMixin (base) {
   return class extends base {
@@ -204,3 +214,31 @@ function DescribedMixin (base) {
   }
 }
 exports.DescribedMixin = DescribedMixin
+
+function DeserializedMixin (base) {
+  return class extends base {
+    constructor (state, recursor) {
+      super({
+        ctor: state[0],
+        pointer: state[1],
+        stringTag: state[2],
+        unwrapped: state[3],
+        isArray: state[4],
+        isIterable: state[5],
+        isList: state[6]
+      })
+
+      if (recursor) {
+        let replayState
+        this.createRecursor = () => {
+          const replay = recursorUtils.replay(replayState, () => ({ size: -1, next: recursor }))
+          replayState = replay.state
+          return replay.recursor.next
+        }
+      } else {
+        this.createRecursor = () => () => null
+      }
+    }
+  }
+}
+exports.DeserializedMixin = DeserializedMixin

lib/complexValues/promise.js

@@ -11,6 +11,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (props) {
+  return new DeserializedPromiseValue(props)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('PromiseValue')
 exports.tag = tag
 
@@ -27,3 +32,9 @@ class DescribedPromiseValue extends object.DescribedMixin(PromiseValue) {
   }
 }
 
+class DeserializedPromiseValue extends object.DeserializedMixin(PromiseValue) {
+  compare (expected) {
+    // Deserialized promises can never be compared using object references.
+    return super.compare(expected)
+  }
+}

lib/complexValues/regexp.js

@@ -15,6 +15,11 @@ function describe (props) {
 }
 exports.describe = describe
 
+function deserialize (state, recursor) {
+  return new DeserializedRegexpValue(state, recursor)
+}
+exports.deserialize = deserialize
+
 const tag = Symbol('RegexpValue')
 exports.tag = tag
 
@@ -56,7 +61,19 @@ class RegexpValue extends object.ObjectValue {
       }
     })
   }
+
+  serialize () {
+    return [this.flags, this.source, super.serialize()]
+  }
 }
 Object.defineProperty(RegexpValue.prototype, 'tag', { value: tag })
 
 const DescribedRegexpValue = object.DescribedMixin(RegexpValue)
+
+class DeserializedRegexpValue extends object.DeserializedMixin(RegexpValue) {
+  constructor (state, recursor) {
+    super(state[2], recursor)
+    this.flags = state[0]
+    this.source = state[1]
+  }
+}