Add a dependency on github.com/exponent-io/jsonpath

Godeps/Godeps.json

@@ -889,6 +889,10 @@
 			"ImportPath": "github.com/evanphx/json-patch",
 			"Rev": "465937c80b3c07a7c7ad20cc934898646a91c1de"
 		},
+		{
+			"ImportPath": "github.com/exponent-io/jsonpath",
+			"Rev": "d6023ce2651d8eafb5c75bb0c7167536102ec9f5"
+		},
 		{
 			"ImportPath": "github.com/fsnotify/fsnotify",
 			"Comment": "v1.3.1-1-gf12c623",

Godeps/LICENSES

@@ -31026,6 +31026,35 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ================================================================================
 
 
+================================================================================
+= vendor/github.com/exponent-io/jsonpath licensed under: =
+
+The MIT License (MIT)
+
+Copyright (c) 2015 Exponent Labs LLC
+
+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/exponent-io/jsonpath/LICENSE 42f582355f11b1d4bc8615214b7f0c38  -
+================================================================================
+
+
 ================================================================================
 = vendor/github.com/fsnotify/fsnotify licensed under: =
 

vendor/github.com/exponent-io/jsonpath/.gitignore

@@ -0,0 +1,24 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof

vendor/github.com/exponent-io/jsonpath/.travis.yml

@@ -0,0 +1,5 @@
+language: go
+
+go:
+  - 1.5
+  - tip

vendor/github.com/exponent-io/jsonpath/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Exponent Labs LLC
+
+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/exponent-io/jsonpath/README.md

@@ -0,0 +1,66 @@
+[![GoDoc](https://godoc.org/github.com/exponent-io/jsonpath?status.svg)](https://godoc.org/github.com/exponent-io/jsonpath)
+[![Build Status](https://travis-ci.org/exponent-io/jsonpath.svg?branch=master)](https://travis-ci.org/exponent-io/jsonpath)
+
+# jsonpath
+
+This package extends the [json.Decoder](https://golang.org/pkg/encoding/json/#Decoder) to support navigating a stream of JSON tokens. You should be able to use this extended Decoder places where a json.Decoder would have been used.
+
+This Decoder has the following enhancements...
+ * The [Scan](https://godoc.org/github.com/exponent-io/jsonpath/#Decoder.Scan) method supports scanning a JSON stream while extracting particular values along the way using [PathActions](https://godoc.org/github.com/exponent-io/jsonpath#PathActions).
+ * The [SeekTo](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.SeekTo) method supports seeking forward in a JSON token stream to a particular path.
+ * The [Path](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.Path) method returns the path of the most recently parsed token.
+ * The [Token](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.Token) method has been modified to distinguish between strings that are object keys and strings that are values. Object key strings are returned as the [KeyString](https://godoc.org/github.com/exponent-io/jsonpath#KeyString) type rather than a native string.
+
+## Installation
+
+    go get -u github.com/exponent-io/jsonpath
+
+## Example Usage
+
+#### SeekTo
+
+```go
+import "github.com/exponent-io/jsonpath"
+
+var j = []byte(`[
+  {"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10}},
+  {"Space": "RGB",   "Point": {"R": 98, "G": 218, "B": 255}}
+]`)
+
+w := json.NewDecoder(bytes.NewReader(j))
+var v interface{}
+
+w.SeekTo(1, "Point", "G")
+w.Decode(&v) // v is 218
+```
+
+#### Scan with PathActions
+
+```go
+var j = []byte(`{"colors":[
+  {"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10, "A": 58}},
+  {"Space": "RGB",   "Point": {"R": 98, "G": 218, "B": 255, "A": 231}}
+]}`)
+
+var actions PathActions
+
+// Extract the value at Point.A
+actions.Add(func(d *Decoder) error {
+  var alpha int
+  err := d.Decode(&alpha)
+  fmt.Printf("Alpha: %v\n", alpha)
+  return err
+}, "Point", "A")
+
+w := NewDecoder(bytes.NewReader(j))
+w.SeekTo("colors", 0)
+
+var ok = true
+var err error
+for ok {
+  ok, err = w.Scan(&actions)
+  if err != nil && err != io.EOF {
+    panic(err)
+  }
+}
+```

vendor/github.com/exponent-io/jsonpath/decoder.go

@@ -0,0 +1,210 @@
+package jsonpath
+
+import (
+	"encoding/json"
+	"io"
+)
+
+// KeyString is returned from Decoder.Token to represent each key in a JSON object value.
+type KeyString string
+
+// Decoder extends the Go runtime's encoding/json.Decoder to support navigating in a stream of JSON tokens.
+type Decoder struct {
+	json.Decoder
+
+	path    JsonPath
+	context jsonContext
+}
+
+// NewDecoder creates a new instance of the extended JSON Decoder.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{Decoder: *json.NewDecoder(r)}
+}
+
+// SeekTo causes the Decoder to move forward to a given path in the JSON structure.
+//
+// The path argument must consist of strings or integers. Each string specifies an JSON object key, and
+// each integer specifies an index into a JSON array.
+//
+// Consider the JSON structure
+//
+//  { "a": [0,"s",12e4,{"b":0,"v":35} ] }
+//
+// SeekTo("a",3,"v") will move to the value referenced by the "a" key in the current object,
+// followed by a move to the 4th value (index 3) in the array, followed by a move to the value at key "v".
+// In this example, a subsequent call to the decoder's Decode() would unmarshal the value 35.
+//
+// SeekTo returns a boolean value indicating whether a match was found.
+//
+// Decoder is intended to be used with a stream of tokens. As a result it navigates forward only.
+func (d *Decoder) SeekTo(path ...interface{}) (bool, error) {
+
+	if len(path) == 0 {
+		return len(d.path) == 0, nil
+	}
+	last := len(path) - 1
+	if i, ok := path[last].(int); ok {
+		path[last] = i - 1
+	}
+
+	for {
+		if d.path.Equal(path) {
+			return true, nil
+		}
+		_, err := d.Token()
+		if err == io.EOF {
+			return false, nil
+		} else if err != nil {
+			return false, err
+		}
+	}
+}
+
+// Decode reads the next JSON-encoded value from its input and stores it in the value pointed to by v. This is
+// equivalent to encoding/json.Decode().
+func (d *Decoder) Decode(v interface{}) error {
+	switch d.context {
+	case objValue:
+		d.context = objKey
+		break
+	case arrValue:
+		d.path.incTop()
+		break
+	}
+	return d.Decoder.Decode(v)
+}
+
+// Path returns a slice of string and/or int values representing the path from the root of the JSON object to the
+// position of the most-recently parsed token.
+func (d *Decoder) Path() JsonPath {
+	p := make(JsonPath, len(d.path))
+	copy(p, d.path)
+	return p
+}
+
+// Token is equivalent to the Token() method on json.Decoder. The primary difference is that it distinguishes
+// between strings that are keys and and strings that are values. String tokens that are object keys are returned as a
+// KeyString rather than as a native string.
+func (d *Decoder) Token() (json.Token, error) {
+	t, err := d.Decoder.Token()
+	if err != nil {
+		return t, err
+	}
+
+	if t == nil {
+		switch d.context {
+		case objValue:
+			d.context = objKey
+			break
+		case arrValue:
+			d.path.incTop()
+			break
+		}
+		return t, err
+	}
+
+	switch t := t.(type) {
+	case json.Delim:
+		switch t {
+		case json.Delim('{'):
+			if d.context == arrValue {
+				d.path.incTop()
+			}
+			d.path.push("")
+			d.context = objKey
+			break
+		case json.Delim('}'):
+			d.path.pop()
+			d.context = d.path.inferContext()
+			break
+		case json.Delim('['):
+			if d.context == arrValue {
+				d.path.incTop()
+			}
+			d.path.push(-1)
+			d.context = arrValue
+			break
+		case json.Delim(']'):
+			d.path.pop()
+			d.context = d.path.inferContext()
+			break
+		}
+	case float64, json.Number, bool:
+		switch d.context {
+		case objValue:
+			d.context = objKey
+			break
+		case arrValue:
+			d.path.incTop()
+			break
+		}
+		break
+	case string:
+		switch d.context {
+		case objKey:
+			d.path.nameTop(t)
+			d.context = objValue
+			return KeyString(t), err
+		case objValue:
+			d.context = objKey
+		case arrValue:
+			d.path.incTop()
+		}
+		break
+	}
+
+	return t, err
+}
+
+// Scan moves forward over the JSON stream consuming all the tokens at the current level (current object, current array)
+// invoking each matching PathAction along the way.
+//
+// Scan returns true if there are more contiguous values to scan (for example in an array).
+func (d *Decoder) Scan(ext *PathActions) (bool, error) {
+
+	rootPath := d.Path()
+
+	// If this is an array path, increment the root path in our local copy.
+	if rootPath.inferContext() == arrValue {
+		rootPath.incTop()
+	}
+
+	for {
+		// advance the token position
+		_, err := d.Token()
+		if err != nil {
+			return false, err
+		}
+
+	match:
+		var relPath JsonPath
+
+		// capture the new JSON path
+		path := d.Path()
+
+		if len(path) > len(rootPath) {
+			// capture the path relative to where the scan started
+			relPath = path[len(rootPath):]
+		} else {
+			// if the path is not longer than the root, then we are done with this scan
+			// return boolean flag indicating if there are more items to scan at the same level
+			return d.Decoder.More(), nil
+		}
+
+		// match the relative path against the path actions
+		if node := ext.node.match(relPath); node != nil {
+			if node.action != nil {
+				// we have a match so execute the action
+				err = node.action(d)
+				if err != nil {
+					return d.Decoder.More(), err
+				}
+				// The action may have advanced the decoder. If we are in an array, advancing it further would
+				// skip tokens. So, if we are scanning an array, jump to the top without advancing the token.
+				if d.path.inferContext() == arrValue && d.Decoder.More() {
+					goto match
+				}
+			}
+		}
+	}
+}

vendor/github.com/exponent-io/jsonpath/path.go

@@ -0,0 +1,67 @@
+// Extends the Go runtime's json.Decoder enabling navigation of a stream of json tokens.
+package jsonpath
+
+import "fmt"
+
+type jsonContext int
+
+const (
+	none jsonContext = iota
+	objKey
+	objValue
+	arrValue
+)
+
+// AnyIndex can be used in a pattern to match any array index.
+const AnyIndex = -2
+
+// JsonPath is a slice of strings and/or integers. Each string specifies an JSON object key, and
+// each integer specifies an index into a JSON array.
+type JsonPath []interface{}
+
+func (p *JsonPath) push(n interface{}) { *p = append(*p, n) }
+func (p *JsonPath) pop()               { *p = (*p)[:len(*p)-1] }
+
+// increment the index at the top of the stack (must be an array index)
+func (p *JsonPath) incTop() { (*p)[len(*p)-1] = (*p)[len(*p)-1].(int) + 1 }
+
+// name the key at the top of the stack (must be an object key)
+func (p *JsonPath) nameTop(n string) { (*p)[len(*p)-1] = n }
+
+// infer the context from the item at the top of the stack
+func (p *JsonPath) inferContext() jsonContext {
+	if len(*p) == 0 {
+		return none
+	}
+	t := (*p)[len(*p)-1]
+	switch t.(type) {
+	case string:
+		return objKey
+	case int:
+		return arrValue
+	default:
+		panic(fmt.Sprintf("Invalid stack type %T", t))
+	}
+}
+
+// Equal tests for equality between two JsonPath types.
+func (p *JsonPath) Equal(o JsonPath) bool {
+	if len(*p) != len(o) {
+		return false
+	}
+	for i, v := range *p {
+		if v != o[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func (p *JsonPath) HasPrefix(o JsonPath) bool {
+	for i, v := range o {
+		if v != (*p)[i] {
+			return false
+		}
+	}
+	return true
+}

vendor/github.com/exponent-io/jsonpath/pathaction.go

@@ -0,0 +1,61 @@
+package jsonpath
+
+// pathNode is used to construct a trie of paths to be matched
+type pathNode struct {
+	matchOn    interface{} // string, or integer
+	childNodes []pathNode
+	action     DecodeAction
+}
+
+// match climbs the trie to find a node that matches the given JSON path.
+func (n *pathNode) match(path JsonPath) *pathNode {
+	var node *pathNode = n
+	for _, ps := range path {
+		found := false
+		for i, n := range node.childNodes {
+			if n.matchOn == ps {
+				node = &node.childNodes[i]
+				found = true
+				break
+			} else if _, ok := ps.(int); ok && n.matchOn == AnyIndex {
+				node = &node.childNodes[i]
+				found = true
+				break
+			}
+		}
+		if !found {
+			return nil
+		}
+	}
+	return node
+}
+
+// PathActions represents a collection of DecodeAction functions that should be called at certain path positions
+// when scanning the JSON stream. PathActions can be created once and used many times in one or more JSON streams.
+type PathActions struct {
+	node pathNode
+}
+
+// DecodeAction handlers are called by the Decoder when scanning objects. See PathActions.Add for more detail.
+type DecodeAction func(d *Decoder) error
+
+// Add specifies an action to call on the Decoder when the specified path is encountered.
+func (je *PathActions) Add(action DecodeAction, path ...interface{}) {
+
+	var node *pathNode = &je.node
+	for _, ps := range path {
+		found := false
+		for i, n := range node.childNodes {
+			if n.matchOn == ps {
+				node = &node.childNodes[i]
+				found = true
+				break
+			}
+		}
+		if !found {
+			node.childNodes = append(node.childNodes, pathNode{matchOn: ps})
+			node = &node.childNodes[len(node.childNodes)-1]
+		}
+	}
+	node.action = action
+}