Vendor mitchellh/hashstructure

Godeps/Godeps.json

@@ -599,6 +599,10 @@
 			"ImportPath": "github.com/mitchellh/go-linereader",
 			"Rev": "07bab5fdd9580500aea6ada0e09df4aa28e68abd"
 		},
+		{
+			"ImportPath": "github.com/mitchellh/hashstructure",
+			"Rev": "6b17d669fac5e2f71c16658d781ec3fdd3802b69"
+		},
 		{
 			"ImportPath": "github.com/mitchellh/mapstructure",
 			"Rev": "281073eb9eb092240d33ef253c404f1cca550309"

vendor/github.com/mitchellh/hashstructure/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Mitchell Hashimoto
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/mitchellh/hashstructure/README.md

@@ -0,0 +1,61 @@
+# hashstructure
+
+hashstructure is a Go library for creating a unique hash value
+for arbitrary values in Go.
+
+This can be used to key values in a hash (for use in a map, set, etc.)
+that are complex. The most common use case is comparing two values without
+sending data across the network, caching values locally (de-dup), and so on.
+
+## Features
+
+  * Hash any arbitrary Go value, including complex types.
+
+  * Tag a struct field to ignore it and not affect the hash value.
+
+  * Tag a slice type struct field to treat it as a set where ordering
+    doesn't affect the hash code but the field itself is still taken into
+    account to create the hash value.
+
+  * Optionally specify a custom hash function to optimize for speed, collision
+    avoidance for your data set, etc.
+
+## Installation
+
+Standard `go get`:
+
+```
+$ go get github.com/mitchellh/hashstructure
+```
+
+## Usage & Example
+
+For usage and examples see the [Godoc](http://godoc.org/github.com/mitchellh/hashstructure).
+
+A quick code example is shown below:
+
+
+	type ComplexStruct struct {
+		Name     string
+		Age      uint
+		Metadata map[string]interface{}
+	}
+
+	v := ComplexStruct{
+		Name: "mitchellh",
+		Age:  64,
+		Metadata: map[string]interface{}{
+			"car":      true,
+			"location": "California",
+			"siblings": []string{"Bob", "John"},
+		},
+	}
+
+	hash, err := hashstructure.Hash(v, nil)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("%d", hash)
+	// Output:
+	// 2307517237273902113

vendor/github.com/mitchellh/hashstructure/hashstructure.go

@@ -0,0 +1,323 @@
+package hashstructure
+
+import (
+	"encoding/binary"
+	"fmt"
+	"hash"
+	"hash/fnv"
+	"reflect"
+)
+
+// HashOptions are options that are available for hashing.
+type HashOptions struct {
+	// Hasher is the hash function to use. If this isn't set, it will
+	// default to FNV.
+	Hasher hash.Hash64
+
+	// TagName is the struct tag to look at when hashing the structure.
+	// By default this is "hash".
+	TagName string
+}
+
+// Hash returns the hash value of an arbitrary value.
+//
+// If opts is nil, then default options will be used. See HashOptions
+// for the default values.
+//
+// Notes on the value:
+//
+//   * Unexported fields on structs are ignored and do not affect the
+//     hash value.
+//
+//   * Adding an exported field to a struct with the zero value will change
+//     the hash value.
+//
+// For structs, the hashing can be controlled using tags. For example:
+//
+//    struct {
+//        Name string
+//        UUID string `hash:"ignore"`
+//    }
+//
+// The available tag values are:
+//
+//   * "ignore" - The field will be ignored and not affect the hash code.
+//
+//   * "set" - The field will be treated as a set, where ordering doesn't
+//             affect the hash code. This only works for slices.
+//
+func Hash(v interface{}, opts *HashOptions) (uint64, error) {
+	// Create default options
+	if opts == nil {
+		opts = &HashOptions{}
+	}
+	if opts.Hasher == nil {
+		opts.Hasher = fnv.New64()
+	}
+	if opts.TagName == "" {
+		opts.TagName = "hash"
+	}
+
+	// Reset the hash
+	opts.Hasher.Reset()
+
+	// Create our walker and walk the structure
+	w := &walker{
+		h:   opts.Hasher,
+		tag: opts.TagName,
+	}
+	return w.visit(reflect.ValueOf(v), nil)
+}
+
+type walker struct {
+	h   hash.Hash64
+	tag string
+}
+
+type visitOpts struct {
+	// Flags are a bitmask of flags to affect behavior of this visit
+	Flags visitFlag
+
+	// Information about the struct containing this field
+	Struct      interface{}
+	StructField string
+}
+
+func (w *walker) visit(v reflect.Value, opts *visitOpts) (uint64, error) {
+	// Loop since these can be wrapped in multiple layers of pointers
+	// and interfaces.
+	for {
+		// If we have an interface, dereference it. We have to do this up
+		// here because it might be a nil in there and the check below must
+		// catch that.
+		if v.Kind() == reflect.Interface {
+			v = v.Elem()
+			continue
+		}
+
+		if v.Kind() == reflect.Ptr {
+			v = reflect.Indirect(v)
+			continue
+		}
+
+		break
+	}
+
+	// If it is nil, treat it like a zero.
+	if !v.IsValid() {
+		var tmp int8
+		v = reflect.ValueOf(tmp)
+	}
+
+	// Binary writing can use raw ints, we have to convert to
+	// a sized-int, we'll choose the largest...
+	switch v.Kind() {
+	case reflect.Int:
+		v = reflect.ValueOf(int64(v.Int()))
+	case reflect.Uint:
+		v = reflect.ValueOf(uint64(v.Uint()))
+	case reflect.Bool:
+		var tmp int8
+		if v.Bool() {
+			tmp = 1
+		}
+		v = reflect.ValueOf(tmp)
+	}
+
+	k := v.Kind()
+
+	// We can shortcut numeric values by directly binary writing them
+	if k >= reflect.Int && k <= reflect.Complex64 {
+		// A direct hash calculation
+		w.h.Reset()
+		err := binary.Write(w.h, binary.LittleEndian, v.Interface())
+		return w.h.Sum64(), err
+	}
+
+	switch k {
+	case reflect.Array:
+		var h uint64
+		l := v.Len()
+		for i := 0; i < l; i++ {
+			current, err := w.visit(v.Index(i), nil)
+			if err != nil {
+				return 0, err
+			}
+
+			h = hashUpdateOrdered(w.h, h, current)
+		}
+
+		return h, nil
+
+	case reflect.Map:
+		var includeMap IncludableMap
+		if opts != nil && opts.Struct != nil {
+			if v, ok := opts.Struct.(IncludableMap); ok {
+				includeMap = v
+			}
+		}
+
+		// Build the hash for the map. We do this by XOR-ing all the key
+		// and value hashes. This makes it deterministic despite ordering.
+		var h uint64
+		for _, k := range v.MapKeys() {
+			v := v.MapIndex(k)
+			if includeMap != nil {
+				incl, err := includeMap.HashIncludeMap(
+					opts.StructField, k.Interface(), v.Interface())
+				if err != nil {
+					return 0, err
+				}
+				if !incl {
+					continue
+				}
+			}
+
+			kh, err := w.visit(k, nil)
+			if err != nil {
+				return 0, err
+			}
+			vh, err := w.visit(v, nil)
+			if err != nil {
+				return 0, err
+			}
+
+			fieldHash := hashUpdateOrdered(w.h, kh, vh)
+			h = hashUpdateUnordered(h, fieldHash)
+		}
+
+		return h, nil
+
+	case reflect.Struct:
+		var include Includable
+		parent := v.Interface()
+		if impl, ok := parent.(Includable); ok {
+			include = impl
+		}
+
+		t := v.Type()
+		h, err := w.visit(reflect.ValueOf(t.Name()), nil)
+		if err != nil {
+			return 0, err
+		}
+
+		l := v.NumField()
+		for i := 0; i < l; i++ {
+			if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
+				var f visitFlag
+				fieldType := t.Field(i)
+				if fieldType.PkgPath != "" {
+					// Unexported
+					continue
+				}
+
+				tag := fieldType.Tag.Get(w.tag)
+				if tag == "ignore" {
+					// Ignore this field
+					continue
+				}
+
+				// Check if we implement includable and check it
+				if include != nil {
+					incl, err := include.HashInclude(fieldType.Name, v)
+					if err != nil {
+						return 0, err
+					}
+					if !incl {
+						continue
+					}
+				}
+
+				switch tag {
+				case "set":
+					f |= visitFlagSet
+				}
+
+				kh, err := w.visit(reflect.ValueOf(fieldType.Name), nil)
+				if err != nil {
+					return 0, err
+				}
+
+				vh, err := w.visit(v, &visitOpts{
+					Flags:       f,
+					Struct:      parent,
+					StructField: fieldType.Name,
+				})
+				if err != nil {
+					return 0, err
+				}
+
+				fieldHash := hashUpdateOrdered(w.h, kh, vh)
+				h = hashUpdateUnordered(h, fieldHash)
+			}
+		}
+
+		return h, nil
+
+	case reflect.Slice:
+		// We have two behaviors here. If it isn't a set, then we just
+		// visit all the elements. If it is a set, then we do a deterministic
+		// hash code.
+		var h uint64
+		var set bool
+		if opts != nil {
+			set = (opts.Flags & visitFlagSet) != 0
+		}
+		l := v.Len()
+		for i := 0; i < l; i++ {
+			current, err := w.visit(v.Index(i), nil)
+			if err != nil {
+				return 0, err
+			}
+
+			if set {
+				h = hashUpdateUnordered(h, current)
+			} else {
+				h = hashUpdateOrdered(w.h, h, current)
+			}
+		}
+
+		return h, nil
+
+	case reflect.String:
+		// Directly hash
+		w.h.Reset()
+		_, err := w.h.Write([]byte(v.String()))
+		return w.h.Sum64(), err
+
+	default:
+		return 0, fmt.Errorf("unknown kind to hash: %s", k)
+	}
+
+	return 0, nil
+}
+
+func hashUpdateOrdered(h hash.Hash64, a, b uint64) uint64 {
+	// For ordered updates, use a real hash function
+	h.Reset()
+
+	// We just panic if the binary writes fail because we are writing
+	// an int64 which should never be fail-able.
+	e1 := binary.Write(h, binary.LittleEndian, a)
+	e2 := binary.Write(h, binary.LittleEndian, b)
+	if e1 != nil {
+		panic(e1)
+	}
+	if e2 != nil {
+		panic(e2)
+	}
+
+	return h.Sum64()
+}
+
+func hashUpdateUnordered(a, b uint64) uint64 {
+	return a ^ b
+}
+
+// visitFlag is used as a bitmask for affecting visit behavior
+type visitFlag uint
+
+const (
+	visitFlagInvalid visitFlag = iota
+	visitFlagSet               = iota << 1
+)

vendor/github.com/mitchellh/hashstructure/include.go

@@ -0,0 +1,15 @@
+package hashstructure
+
+// Includable is an interface that can optionally be implemented by
+// a struct. It will be called for each field in the struct to check whether
+// it should be included in the hash.
+type Includable interface {
+	HashInclude(field string, v interface{}) (bool, error)
+}
+
+// IncludableMap is an interface that can optionally be implemented by
+// a struct. It will be called when a map-type field is found to ask the
+// struct if the map item should be included in the hash.
+type IncludableMap interface {
+	HashIncludeMap(field string, k, v interface{}) (bool, error)
+}