1 files changed, 308 insertions, 0 deletions
diff --git a/vendor/github.com/shurcooL/graphql/internal/jsonutil/graphql.go b/vendor/github.com/shurcooL/graphql/internal/jsonutil/graphql.go
new file mode 100644
index 00000000..9e75791d
--- /dev/null
+++ b/vendor/github.com/shurcooL/graphql/internal/jsonutil/graphql.go
@@ -0,0 +1,308 @@
+// Package jsonutil provides a function for decoding JSON
+// into a GraphQL query data structure.
+package jsonutil
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+)
+
+// UnmarshalGraphQL parses the JSON-encoded GraphQL response data and stores
+// the result in the GraphQL query data structure pointed to by v.
+//
+// The implementation is created on top of the JSON tokenizer available
+// in "encoding/json".Decoder.
+func UnmarshalGraphQL(data []byte, v interface{}) error {
+	dec := json.NewDecoder(bytes.NewReader(data))
+	dec.UseNumber()
+	err := (&decoder{tokenizer: dec}).Decode(v)
+	if err != nil {
+		return err
+	}
+	tok, err := dec.Token()
+	switch err {
+	case io.EOF:
+		// Expect to get io.EOF. There shouldn't be any more
+		// tokens left after we've decoded v successfully.
+		return nil
+	case nil:
+		return fmt.Errorf("invalid token '%v' after top-level value", tok)
+	default:
+		return err
+	}
+}
+
+// decoder is a JSON decoder that performs custom unmarshaling behavior
+// for GraphQL query data structures. It's implemented on top of a JSON tokenizer.
+type decoder struct {
+	tokenizer interface {
+		Token() (json.Token, error)
+	}
+
+	// Stack of what part of input JSON we're in the middle of - objects, arrays.
+	parseState []json.Delim
+
+	// Stacks of values where to unmarshal.
+	// The top of each stack is the reflect.Value where to unmarshal next JSON value.
+	//
+	// The reason there's more than one stack is because we might be unmarshaling
+	// a single JSON value into multiple GraphQL fragments or embedded structs, so
+	// we keep track of them all.
+	vs [][]reflect.Value
+}
+
+// Decode decodes a single JSON value from d.tokenizer into v.
+func (d *decoder) Decode(v interface{}) error {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() != reflect.Ptr {
+		return fmt.Errorf("cannot decode into non-pointer %T", v)
+	}
+	d.vs = [][]reflect.Value{{rv.Elem()}}
+	return d.decode()
+}
+
+// decode decodes a single JSON value from d.tokenizer into d.vs.
+func (d *decoder) decode() error {
+	// The loop invariant is that the top of each d.vs stack
+	// is where we try to unmarshal the next JSON value we see.
+	for len(d.vs) > 0 {
+		tok, err := d.tokenizer.Token()
+		if err == io.EOF {
+			return errors.New("unexpected end of JSON input")
+		} else if err != nil {
+			return err
+		}
+
+		switch {
+
+		// Are we inside an object and seeing next key (rather than end of object)?
+		case d.state() == '{' && tok != json.Delim('}'):
+			key, ok := tok.(string)
+			if !ok {
+				return errors.New("unexpected non-key in JSON input")
+			}
+			someFieldExist := false
+			for i := range d.vs {
+				v := d.vs[i][len(d.vs[i])-1]
+				if v.Kind() == reflect.Ptr {
+					v = v.Elem()
+				}
+				var f reflect.Value
+				if v.Kind() == reflect.Struct {
+					f = fieldByGraphQLName(v, key)
+					if f.IsValid() {
+						someFieldExist = true
+					}
+				}
+				d.vs[i] = append(d.vs[i], f)
+			}
+			if !someFieldExist {
+				return fmt.Errorf("struct field for %s doesn't exist in any of %v places to unmarshal", key, len(d.vs))
+			}
+
+			// We've just consumed the current token, which was the key.
+			// Read the next token, which should be the value, and let the rest of code process it.
+			tok, err = d.tokenizer.Token()
+			if err == io.EOF {
+				return errors.New("unexpected end of JSON input")
+			} else if err != nil {
+				return err
+			}
+
+		// Are we inside an array and seeing next value (rather than end of array)?
+		case d.state() == '[' && tok != json.Delim(']'):
+			someSliceExist := false
+			for i := range d.vs {
+				v := d.vs[i][len(d.vs[i])-1]
+				if v.Kind() == reflect.Ptr {
+					v = v.Elem()
+				}
+				var f reflect.Value
+				if v.Kind() == reflect.Slice {
+					v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem()))) // v = append(v, T).
+					f = v.Index(v.Len() - 1)
+					someSliceExist = true
+				}
+				d.vs[i] = append(d.vs[i], f)
+			}
+			if !someSliceExist {
+				return fmt.Errorf("slice doesn't exist in any of %v places to unmarshal", len(d.vs))
+			}
+		}
+
+		switch tok := tok.(type) {
+		case string, json.Number, bool, nil:
+			// Value.
+
+			for i := range d.vs {
+				v := d.vs[i][len(d.vs[i])-1]
+				if !v.IsValid() {
+					continue
+				}
+				err := unmarshalValue(tok, v)
+				if err != nil {
+					return err
+				}
+			}
+			d.popAllVs()
+
+		case json.Delim:
+			switch tok {
+			case '{':
+				// Start of object.
+
+				d.pushState(tok)
+
+				frontier := make([]reflect.Value, len(d.vs)) // Places to look for GraphQL fragments/embedded structs.
+				for i := range d.vs {
+					v := d.vs[i][len(d.vs[i])-1]
+					frontier[i] = v
+					// TODO: Do this recursively or not? Add a test case if needed.
+					if v.Kind() == reflect.Ptr && v.IsNil() {
+						v.Set(reflect.New(v.Type().Elem())) // v = new(T).
+					}
+				}
+				// Find GraphQL fragments/embedded structs recursively, adding to frontier
+				// as new ones are discovered and exploring them further.
+				for len(frontier) > 0 {
+					v := frontier[0]
+					frontier = frontier[1:]
+					if v.Kind() == reflect.Ptr {
+						v = v.Elem()
+					}
+					if v.Kind() != reflect.Struct {
+						continue
+					}
+					for i := 0; i < v.NumField(); i++ {
+						if isGraphQLFragment(v.Type().Field(i)) || v.Type().Field(i).Anonymous {
+							// Add GraphQL fragment or embedded struct.
+							d.vs = append(d.vs, []reflect.Value{v.Field(i)})
+							frontier = append(frontier, v.Field(i))
+						}
+					}
+				}
+			case '[':
+				// Start of array.
+
+				d.pushState(tok)
+
+				for i := range d.vs {
+					v := d.vs[i][len(d.vs[i])-1]
+					// TODO: Confirm this is needed, write a test case.
+					//if v.Kind() == reflect.Ptr && v.IsNil() {
+					//	v.Set(reflect.New(v.Type().Elem())) // v = new(T).
+					//}
+
+					// Reset slice to empty (in case it had non-zero initial value).
+					if v.Kind() == reflect.Ptr {
+						v = v.Elem()
+					}
+					if v.Kind() != reflect.Slice {
+						continue
+					}
+					v.Set(reflect.MakeSlice(v.Type(), 0, 0)) // v = make(T, 0, 0).
+				}
+			case '}', ']':
+				// End of object or array.
+				d.popAllVs()
+				d.popState()
+			default:
+				return errors.New("unexpected delimiter in JSON input")
+			}
+		default:
+			return errors.New("unexpected token in JSON input")
+		}
+	}
+	return nil
+}
+
+// pushState pushes a new parse state s onto the stack.
+func (d *decoder) pushState(s json.Delim) {
+	d.parseState = append(d.parseState, s)
+}
+
+// popState pops a parse state (already obtained) off the stack.
+// The stack must be non-empty.
+func (d *decoder) popState() {
+	d.parseState = d.parseState[:len(d.parseState)-1]
+}
+
+// state reports the parse state on top of stack, or 0 if empty.
+func (d *decoder) state() json.Delim {
+	if len(d.parseState) == 0 {
+		return 0
+	}
+	return d.parseState[len(d.parseState)-1]
+}
+
+// popAllVs pops from all d.vs stacks, keeping only non-empty ones.
+func (d *decoder) popAllVs() {
+	var nonEmpty [][]reflect.Value
+	for i := range d.vs {
+		d.vs[i] = d.vs[i][:len(d.vs[i])-1]
+		if len(d.vs[i]) > 0 {
+			nonEmpty = append(nonEmpty, d.vs[i])
+		}
+	}
+	d.vs = nonEmpty
+}
+
+// fieldByGraphQLName returns a struct field of struct v that matches GraphQL name,
+// or invalid reflect.Value if none found.
+func fieldByGraphQLName(v reflect.Value, name string) reflect.Value {
+	for i := 0; i < v.NumField(); i++ {
+		if hasGraphQLName(v.Type().Field(i), name) {
+			return v.Field(i)
+		}
+	}
+	return reflect.Value{}
+}
+
+// hasGraphQLName reports whether struct field f has GraphQL name.
+func hasGraphQLName(f reflect.StructField, name string) bool {
+	value, ok := f.Tag.Lookup("graphql")
+	if !ok {
+		// TODO: caseconv package is relatively slow. Optimize it, then consider using it here.
+		//return caseconv.MixedCapsToLowerCamelCase(f.Name) == name
+		return strings.EqualFold(f.Name, name)
+	}
+	value = strings.TrimSpace(value) // TODO: Parse better.
+	if strings.HasPrefix(value, "...") {
+		// GraphQL fragment. It doesn't have a name.
+		return false
+	}
+	if i := strings.Index(value, "("); i != -1 {
+		value = value[:i]
+	}
+	if i := strings.Index(value, ":"); i != -1 {
+		value = value[:i]
+	}
+	return strings.TrimSpace(value) == name
+}
+
+// isGraphQLFragment reports whether struct field f is a GraphQL fragment.
+func isGraphQLFragment(f reflect.StructField) bool {
+	value, ok := f.Tag.Lookup("graphql")
+	if !ok {
+		return false
+	}
+	value = strings.TrimSpace(value) // TODO: Parse better.
+	return strings.HasPrefix(value, "...")
+}
+
+// unmarshalValue unmarshals JSON value into v.
+func unmarshalValue(value json.Token, v reflect.Value) error {
+	b, err := json.Marshal(value) // TODO: Short-circuit (if profiling says it's worth it).
+	if err != nil {
+		return err
+	}
+	if !v.CanAddr() {
+		return fmt.Errorf("value %v is not addressable", v)
+	}
+	return json.Unmarshal(b, v.Addr().Interface())
+}