1 files changed, 381 insertions, 0 deletions
diff --git a/vendor/github.com/graph-gophers/graphql-go/internal/exec/exec.go b/vendor/github.com/graph-gophers/graphql-go/internal/exec/exec.go
new file mode 100644
index 00000000..6b478487
--- /dev/null
+++ b/vendor/github.com/graph-gophers/graphql-go/internal/exec/exec.go
@@ -0,0 +1,381 @@
+package exec
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"sync"
+	"time"
+
+	"github.com/graph-gophers/graphql-go/errors"
+	"github.com/graph-gophers/graphql-go/internal/exec/resolvable"
+	"github.com/graph-gophers/graphql-go/internal/exec/selected"
+	"github.com/graph-gophers/graphql-go/internal/query"
+	"github.com/graph-gophers/graphql-go/log"
+	"github.com/graph-gophers/graphql-go/trace"
+	"github.com/graph-gophers/graphql-go/types"
+)
+
+type Request struct {
+	selected.Request
+	Limiter                  chan struct{}
+	Tracer                   trace.Tracer
+	Logger                   log.Logger
+	PanicHandler             errors.PanicHandler
+	SubscribeResolverTimeout time.Duration
+}
+
+func (r *Request) handlePanic(ctx context.Context) {
+	if value := recover(); value != nil {
+		r.Logger.LogPanic(ctx, value)
+		r.AddError(r.PanicHandler.MakePanicError(ctx, value))
+	}
+}
+
+type extensionser interface {
+	Extensions() map[string]interface{}
+}
+
+func (r *Request) Execute(ctx context.Context, s *resolvable.Schema, op *types.OperationDefinition) ([]byte, []*errors.QueryError) {
+	var out bytes.Buffer
+	func() {
+		defer r.handlePanic(ctx)
+		sels := selected.ApplyOperation(&r.Request, s, op)
+		r.execSelections(ctx, sels, nil, s, s.Resolver, &out, op.Type == query.Mutation)
+	}()
+
+	if err := ctx.Err(); err != nil {
+		return nil, []*errors.QueryError{errors.Errorf("%s", err)}
+	}
+
+	return out.Bytes(), r.Errs
+}
+
+type fieldToExec struct {
+	field    *selected.SchemaField
+	sels     []selected.Selection
+	resolver reflect.Value
+	out      *bytes.Buffer
+}
+
+func resolvedToNull(b *bytes.Buffer) bool {
+	return bytes.Equal(b.Bytes(), []byte("null"))
+}
+
+func (r *Request) execSelections(ctx context.Context, sels []selected.Selection, path *pathSegment, s *resolvable.Schema, resolver reflect.Value, out *bytes.Buffer, serially bool) {
+	async := !serially && selected.HasAsyncSel(sels)
+
+	var fields []*fieldToExec
+	collectFieldsToResolve(sels, s, resolver, &fields, make(map[string]*fieldToExec))
+
+	if async {
+		var wg sync.WaitGroup
+		wg.Add(len(fields))
+		for _, f := range fields {
+			go func(f *fieldToExec) {
+				defer wg.Done()
+				defer r.handlePanic(ctx)
+				f.out = new(bytes.Buffer)
+				execFieldSelection(ctx, r, s, f, &pathSegment{path, f.field.Alias}, true)
+			}(f)
+		}
+		wg.Wait()
+	} else {
+		for _, f := range fields {
+			f.out = new(bytes.Buffer)
+			execFieldSelection(ctx, r, s, f, &pathSegment{path, f.field.Alias}, true)
+		}
+	}
+
+	out.WriteByte('{')
+	for i, f := range fields {
+		// If a non-nullable child resolved to null, an error was added to the
+		// "errors" list in the response, so this field resolves to null.
+		// If this field is non-nullable, the error is propagated to its parent.
+		if _, ok := f.field.Type.(*types.NonNull); ok && resolvedToNull(f.out) {
+			out.Reset()
+			out.Write([]byte("null"))
+			return
+		}
+
+		if i > 0 {
+			out.WriteByte(',')
+		}
+		out.WriteByte('"')
+		out.WriteString(f.field.Alias)
+		out.WriteByte('"')
+		out.WriteByte(':')
+		out.Write(f.out.Bytes())
+	}
+	out.WriteByte('}')
+}
+
+func collectFieldsToResolve(sels []selected.Selection, s *resolvable.Schema, resolver reflect.Value, fields *[]*fieldToExec, fieldByAlias map[string]*fieldToExec) {
+	for _, sel := range sels {
+		switch sel := sel.(type) {
+		case *selected.SchemaField:
+			field, ok := fieldByAlias[sel.Alias]
+			if !ok { // validation already checked for conflict (TODO)
+				field = &fieldToExec{field: sel, resolver: resolver}
+				fieldByAlias[sel.Alias] = field
+				*fields = append(*fields, field)
+			}
+			field.sels = append(field.sels, sel.Sels...)
+
+		case *selected.TypenameField:
+			_, ok := fieldByAlias[sel.Alias]
+			if !ok {
+				res := reflect.ValueOf(typeOf(sel, resolver))
+				f := s.FieldTypename
+				f.TypeName = res.String()
+
+				sf := &selected.SchemaField{
+					Field:       f,
+					Alias:       sel.Alias,
+					FixedResult: res,
+				}
+
+				field := &fieldToExec{field: sf, resolver: resolver}
+				*fields = append(*fields, field)
+				fieldByAlias[sel.Alias] = field
+			}
+
+		case *selected.TypeAssertion:
+			out := resolver.Method(sel.MethodIndex).Call(nil)
+			if !out[1].Bool() {
+				continue
+			}
+			collectFieldsToResolve(sel.Sels, s, out[0], fields, fieldByAlias)
+
+		default:
+			panic("unreachable")
+		}
+	}
+}
+
+func typeOf(tf *selected.TypenameField, resolver reflect.Value) string {
+	if len(tf.TypeAssertions) == 0 {
+		return tf.Name
+	}
+	for name, a := range tf.TypeAssertions {
+		out := resolver.Method(a.MethodIndex).Call(nil)
+		if out[1].Bool() {
+			return name
+		}
+	}
+	return ""
+}
+
+func execFieldSelection(ctx context.Context, r *Request, s *resolvable.Schema, f *fieldToExec, path *pathSegment, applyLimiter bool) {
+	if applyLimiter {
+		r.Limiter <- struct{}{}
+	}
+
+	var result reflect.Value
+	var err *errors.QueryError
+
+	traceCtx, finish := r.Tracer.TraceField(ctx, f.field.TraceLabel, f.field.TypeName, f.field.Name, !f.field.Async, f.field.Args)
+	defer func() {
+		finish(err)
+	}()
+
+	err = func() (err *errors.QueryError) {
+		defer func() {
+			if panicValue := recover(); panicValue != nil {
+				r.Logger.LogPanic(ctx, panicValue)
+				err = r.PanicHandler.MakePanicError(ctx, panicValue)
+				err.Path = path.toSlice()
+			}
+		}()
+
+		if f.field.FixedResult.IsValid() {
+			result = f.field.FixedResult
+			return nil
+		}
+
+		if err := traceCtx.Err(); err != nil {
+			return errors.Errorf("%s", err) // don't execute any more resolvers if context got cancelled
+		}
+
+		res := f.resolver
+		if f.field.UseMethodResolver() {
+			var in []reflect.Value
+			if f.field.HasContext {
+				in = append(in, reflect.ValueOf(traceCtx))
+			}
+			if f.field.ArgsPacker != nil {
+				in = append(in, f.field.PackedArgs)
+			}
+			callOut := res.Method(f.field.MethodIndex).Call(in)
+			result = callOut[0]
+			if f.field.HasError && !callOut[1].IsNil() {
+				resolverErr := callOut[1].Interface().(error)
+				err := errors.Errorf("%s", resolverErr)
+				err.Path = path.toSlice()
+				err.ResolverError = resolverErr
+				if ex, ok := callOut[1].Interface().(extensionser); ok {
+					err.Extensions = ex.Extensions()
+				}
+				return err
+			}
+		} else {
+			// TODO extract out unwrapping ptr logic to a common place
+			if res.Kind() == reflect.Ptr {
+				res = res.Elem()
+			}
+			result = res.FieldByIndex(f.field.FieldIndex)
+		}
+		return nil
+	}()
+
+	if applyLimiter {
+		<-r.Limiter
+	}
+
+	if err != nil {
+		// If an error occurred while resolving a field, it should be treated as though the field
+		// returned null, and an error must be added to the "errors" list in the response.
+		r.AddError(err)
+		f.out.WriteString("null")
+		return
+	}
+
+	r.execSelectionSet(traceCtx, f.sels, f.field.Type, path, s, result, f.out)
+}
+
+func (r *Request) execSelectionSet(ctx context.Context, sels []selected.Selection, typ types.Type, path *pathSegment, s *resolvable.Schema, resolver reflect.Value, out *bytes.Buffer) {
+	t, nonNull := unwrapNonNull(typ)
+
+	// a reflect.Value of a nil interface will show up as an Invalid value
+	if resolver.Kind() == reflect.Invalid || ((resolver.Kind() == reflect.Ptr || resolver.Kind() == reflect.Interface) && resolver.IsNil()) {
+		// If a field of a non-null type resolves to null (either because the
+		// function to resolve the field returned null or because an error occurred),
+		// add an error to the "errors" list in the response.
+		if nonNull {
+			err := errors.Errorf("graphql: got nil for non-null %q", t)
+			err.Path = path.toSlice()
+			r.AddError(err)
+		}
+		out.WriteString("null")
+		return
+	}
+
+	switch t.(type) {
+	case *types.ObjectTypeDefinition, *types.InterfaceTypeDefinition, *types.Union:
+		r.execSelections(ctx, sels, path, s, resolver, out, false)
+		return
+	}
+
+	// Any pointers or interfaces at this point should be non-nil, so we can get the actual value of them
+	// for serialization
+	if resolver.Kind() == reflect.Ptr || resolver.Kind() == reflect.Interface {
+		resolver = resolver.Elem()
+	}
+
+	switch t := t.(type) {
+	case *types.List:
+		r.execList(ctx, sels, t, path, s, resolver, out)
+
+	case *types.ScalarTypeDefinition:
+		v := resolver.Interface()
+		data, err := json.Marshal(v)
+		if err != nil {
+			panic(errors.Errorf("could not marshal %v: %s", v, err))
+		}
+		out.Write(data)
+
+	case *types.EnumTypeDefinition:
+		var stringer fmt.Stringer = resolver
+		if s, ok := resolver.Interface().(fmt.Stringer); ok {
+			stringer = s
+		}
+		name := stringer.String()
+		var valid bool
+		for _, v := range t.EnumValuesDefinition {
+			if v.EnumValue == name {
+				valid = true
+				break
+			}
+		}
+		if !valid {
+			err := errors.Errorf("Invalid value %s.\nExpected type %s, found %s.", name, t.Name, name)
+			err.Path = path.toSlice()
+			r.AddError(err)
+			out.WriteString("null")
+			return
+		}
+		out.WriteByte('"')
+		out.WriteString(name)
+		out.WriteByte('"')
+
+	default:
+		panic("unreachable")
+	}
+}
+
+func (r *Request) execList(ctx context.Context, sels []selected.Selection, typ *types.List, path *pathSegment, s *resolvable.Schema, resolver reflect.Value, out *bytes.Buffer) {
+	l := resolver.Len()
+	entryouts := make([]bytes.Buffer, l)
+
+	if selected.HasAsyncSel(sels) {
+		// Limit the number of concurrent goroutines spawned as it can lead to large
+		// memory spikes for large lists.
+		concurrency := cap(r.Limiter)
+		sem := make(chan struct{}, concurrency)
+		for i := 0; i < l; i++ {
+			sem <- struct{}{}
+			go func(i int) {
+				defer func() { <-sem }()
+				defer r.handlePanic(ctx)
+				r.execSelectionSet(ctx, sels, typ.OfType, &pathSegment{path, i}, s, resolver.Index(i), &entryouts[i])
+			}(i)
+		}
+		for i := 0; i < concurrency; i++ {
+			sem <- struct{}{}
+		}
+	} else {
+		for i := 0; i < l; i++ {
+			r.execSelectionSet(ctx, sels, typ.OfType, &pathSegment{path, i}, s, resolver.Index(i), &entryouts[i])
+		}
+	}
+
+	_, listOfNonNull := typ.OfType.(*types.NonNull)
+
+	out.WriteByte('[')
+	for i, entryout := range entryouts {
+		// If the list wraps a non-null type and one of the list elements
+		// resolves to null, then the entire list resolves to null.
+		if listOfNonNull && resolvedToNull(&entryout) {
+			out.Reset()
+			out.WriteString("null")
+			return
+		}
+
+		if i > 0 {
+			out.WriteByte(',')
+		}
+		out.Write(entryout.Bytes())
+	}
+	out.WriteByte(']')
+}
+
+func unwrapNonNull(t types.Type) (types.Type, bool) {
+	if nn, ok := t.(*types.NonNull); ok {
+		return nn.OfType, true
+	}
+	return t, false
+}
+
+type pathSegment struct {
+	parent *pathSegment
+	value  interface{}
+}
+
+func (p *pathSegment) toSlice() []interface{} {
+	if p == nil {
+		return nil
+	}
+	return append(p.parent.toSlice(), p.value)
+}