aboutsummaryrefslogtreecommitdiffstats
path: root/vendor/github.com/99designs/gqlgen/codegen/field.go
blob: 264b59ce9a77355230ae224525e84427e4f4f0d0 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
package codegen

import (
	"fmt"
	"go/types"
	"log"
	"reflect"
	"strconv"
	"strings"

	"github.com/99designs/gqlgen/codegen/config"
	"github.com/99designs/gqlgen/codegen/templates"
	"github.com/pkg/errors"
	"github.com/vektah/gqlparser/ast"
)

type Field struct {
	*ast.FieldDefinition

	TypeReference    *config.TypeReference
	GoFieldType      GoFieldType      // The field type in go, if any
	GoReceiverName   string           // The name of method & var receiver in go, if any
	GoFieldName      string           // The name of the method or var in go, if any
	IsResolver       bool             // Does this field need a resolver
	Args             []*FieldArgument // A list of arguments to be passed to this field
	MethodHasContext bool             // If this is bound to a go method, does the method also take a context
	NoErr            bool             // If this is bound to a go method, does that method have an error as the second argument
	Object           *Object          // A link back to the parent object
	Default          interface{}      // The default value
	Directives       []*Directive
}

func (b *builder) buildField(obj *Object, field *ast.FieldDefinition) (*Field, error) {
	dirs, err := b.getDirectives(field.Directives)
	if err != nil {
		return nil, err
	}

	f := Field{
		FieldDefinition: field,
		Object:          obj,
		Directives:      dirs,
		GoFieldName:     templates.ToGo(field.Name),
		GoFieldType:     GoFieldVariable,
		GoReceiverName:  "obj",
	}

	if field.DefaultValue != nil {
		var err error
		f.Default, err = field.DefaultValue.Value(nil)
		if err != nil {
			return nil, errors.Errorf("default value %s is not valid: %s", field.Name, err.Error())
		}
	}

	for _, arg := range field.Arguments {
		newArg, err := b.buildArg(obj, arg)
		if err != nil {
			return nil, err
		}
		f.Args = append(f.Args, newArg)
	}

	if err = b.bindField(obj, &f); err != nil {
		f.IsResolver = true
		log.Println(err.Error())
	}

	if f.IsResolver && !f.TypeReference.IsPtr() && f.TypeReference.IsStruct() {
		f.TypeReference = b.Binder.PointerTo(f.TypeReference)
	}

	return &f, nil
}

func (b *builder) bindField(obj *Object, f *Field) error {
	defer func() {
		if f.TypeReference == nil {
			tr, err := b.Binder.TypeReference(f.Type, nil)
			if err != nil {
				panic(err)
			}
			f.TypeReference = tr
		}
	}()

	switch {
	case f.Name == "__schema":
		f.GoFieldType = GoFieldMethod
		f.GoReceiverName = "ec"
		f.GoFieldName = "introspectSchema"
		return nil
	case f.Name == "__type":
		f.GoFieldType = GoFieldMethod
		f.GoReceiverName = "ec"
		f.GoFieldName = "introspectType"
		return nil
	case obj.Root:
		f.IsResolver = true
		return nil
	case b.Config.Models[obj.Name].Fields[f.Name].Resolver:
		f.IsResolver = true
		return nil
	case obj.Type == config.MapType:
		f.GoFieldType = GoFieldMap
		return nil
	case b.Config.Models[obj.Name].Fields[f.Name].FieldName != "":
		f.GoFieldName = b.Config.Models[obj.Name].Fields[f.Name].FieldName
	}

	target, err := b.findBindTarget(obj.Type.(*types.Named), f.GoFieldName)
	if err != nil {
		return err
	}

	pos := b.Binder.ObjectPosition(target)

	switch target := target.(type) {
	case nil:
		objPos := b.Binder.TypePosition(obj.Type)
		return fmt.Errorf(
			"%s:%d adding resolver method for %s.%s, nothing matched",
			objPos.Filename,
			objPos.Line,
			obj.Name,
			f.Name,
		)

	case *types.Func:
		sig := target.Type().(*types.Signature)
		if sig.Results().Len() == 1 {
			f.NoErr = true
		} else if sig.Results().Len() != 2 {
			return fmt.Errorf("method has wrong number of args")
		}
		params := sig.Params()
		// If the first argument is the context, remove it from the comparison and set
		// the MethodHasContext flag so that the context will be passed to this model's method
		if params.Len() > 0 && params.At(0).Type().String() == "context.Context" {
			f.MethodHasContext = true
			vars := make([]*types.Var, params.Len()-1)
			for i := 1; i < params.Len(); i++ {
				vars[i-1] = params.At(i)
			}
			params = types.NewTuple(vars...)
		}

		if err = b.bindArgs(f, params); err != nil {
			return errors.Wrapf(err, "%s:%d", pos.Filename, pos.Line)
		}

		result := sig.Results().At(0)
		tr, err := b.Binder.TypeReference(f.Type, result.Type())
		if err != nil {
			return err
		}

		// success, args and return type match. Bind to method
		f.GoFieldType = GoFieldMethod
		f.GoReceiverName = "obj"
		f.GoFieldName = target.Name()
		f.TypeReference = tr

		return nil

	case *types.Var:
		tr, err := b.Binder.TypeReference(f.Type, target.Type())
		if err != nil {
			return err
		}

		// success, bind to var
		f.GoFieldType = GoFieldVariable
		f.GoReceiverName = "obj"
		f.GoFieldName = target.Name()
		f.TypeReference = tr

		return nil
	default:
		panic(fmt.Errorf("unknown bind target %T for %s", target, f.Name))
	}
}

// findField attempts to match the name to a struct field with the following
// priorites:
// 1. Any method with a matching name
// 2. Any Fields with a struct tag (see config.StructTag)
// 3. Any fields with a matching name
// 4. Same logic again for embedded fields
func (b *builder) findBindTarget(named *types.Named, name string) (types.Object, error) {
	for i := 0; i < named.NumMethods(); i++ {
		method := named.Method(i)
		if !method.Exported() {
			continue
		}

		if !strings.EqualFold(method.Name(), name) {
			continue
		}

		return method, nil
	}

	strukt, ok := named.Underlying().(*types.Struct)
	if !ok {
		return nil, fmt.Errorf("not a struct")
	}
	return b.findBindStructTarget(strukt, name)
}

func (b *builder) findBindStructTarget(strukt *types.Struct, name string) (types.Object, error) {
	// struct tags have the highest priority
	if b.Config.StructTag != "" {
		var foundField *types.Var
		for i := 0; i < strukt.NumFields(); i++ {
			field := strukt.Field(i)
			if !field.Exported() {
				continue
			}
			tags := reflect.StructTag(strukt.Tag(i))
			if val, ok := tags.Lookup(b.Config.StructTag); ok && equalFieldName(val, name) {
				if foundField != nil {
					return nil, errors.Errorf("tag %s is ambigious; multiple fields have the same tag value of %s", b.Config.StructTag, val)
				}

				foundField = field
			}
		}
		if foundField != nil {
			return foundField, nil
		}
	}

	// Then matching field names
	for i := 0; i < strukt.NumFields(); i++ {
		field := strukt.Field(i)
		if !field.Exported() {
			continue
		}
		if equalFieldName(field.Name(), name) { // aqui!
			return field, nil
		}
	}

	// Then look in embedded structs
	for i := 0; i < strukt.NumFields(); i++ {
		field := strukt.Field(i)
		if !field.Exported() {
			continue
		}

		if !field.Anonymous() {
			continue
		}

		fieldType := field.Type()
		if ptr, ok := fieldType.(*types.Pointer); ok {
			fieldType = ptr.Elem()
		}

		switch fieldType := fieldType.(type) {
		case *types.Named:
			f, err := b.findBindTarget(fieldType, name)
			if err != nil {
				return nil, err
			}
			if f != nil {
				return f, nil
			}
		case *types.Struct:
			f, err := b.findBindStructTarget(fieldType, name)
			if err != nil {
				return nil, err
			}
			if f != nil {
				return f, nil
			}
		default:
			panic(fmt.Errorf("unknown embedded field type %T", field.Type()))
		}
	}

	return nil, nil
}

func (f *Field) HasDirectives() bool {
	return len(f.ImplDirectives()) > 0
}

func (f *Field) DirectiveObjName() string {
	if f.Object.Root {
		return "nil"
	}
	return f.GoReceiverName
}

func (f *Field) ImplDirectives() []*Directive {
	var d []*Directive
	loc := ast.LocationFieldDefinition
	if f.Object.IsInputType() {
		loc = ast.LocationInputFieldDefinition
	}
	for i := range f.Directives {
		if !f.Directives[i].Builtin && f.Directives[i].IsLocation(loc) {
			d = append(d, f.Directives[i])
		}
	}
	return d
}

func (f *Field) IsReserved() bool {
	return strings.HasPrefix(f.Name, "__")
}

func (f *Field) IsMethod() bool {
	return f.GoFieldType == GoFieldMethod
}

func (f *Field) IsVariable() bool {
	return f.GoFieldType == GoFieldVariable
}

func (f *Field) IsMap() bool {
	return f.GoFieldType == GoFieldMap
}

func (f *Field) IsConcurrent() bool {
	if f.Object.DisableConcurrency {
		return false
	}
	return f.MethodHasContext || f.IsResolver
}

func (f *Field) GoNameUnexported() string {
	return templates.ToGoPrivate(f.Name)
}

func (f *Field) ShortInvocation() string {
	return fmt.Sprintf("%s().%s(%s)", f.Object.Definition.Name, f.GoFieldName, f.CallArgs())
}

func (f *Field) ArgsFunc() string {
	if len(f.Args) == 0 {
		return ""
	}

	return "field_" + f.Object.Definition.Name + "_" + f.Name + "_args"
}

func (f *Field) ResolverType() string {
	if !f.IsResolver {
		return ""
	}

	return fmt.Sprintf("%s().%s(%s)", f.Object.Definition.Name, f.GoFieldName, f.CallArgs())
}

func (f *Field) ShortResolverDeclaration() string {
	res := "(ctx context.Context"

	if !f.Object.Root {
		res += fmt.Sprintf(", obj *%s", templates.CurrentImports.LookupType(f.Object.Type))
	}
	for _, arg := range f.Args {
		res += fmt.Sprintf(", %s %s", arg.VarName, templates.CurrentImports.LookupType(arg.TypeReference.GO))
	}

	result := templates.CurrentImports.LookupType(f.TypeReference.GO)
	if f.Object.Stream {
		result = "<-chan " + result
	}

	res += fmt.Sprintf(") (%s, error)", result)
	return res
}

func (f *Field) ComplexitySignature() string {
	res := fmt.Sprintf("func(childComplexity int")
	for _, arg := range f.Args {
		res += fmt.Sprintf(", %s %s", arg.VarName, templates.CurrentImports.LookupType(arg.TypeReference.GO))
	}
	res += ") int"
	return res
}

func (f *Field) ComplexityArgs() string {
	var args []string
	for _, arg := range f.Args {
		args = append(args, "args["+strconv.Quote(arg.Name)+"].("+templates.CurrentImports.LookupType(arg.TypeReference.GO)+")")
	}

	return strings.Join(args, ", ")
}

func (f *Field) CallArgs() string {
	var args []string

	if f.IsResolver {
		args = append(args, "rctx")

		if !f.Object.Root {
			args = append(args, "obj")
		}
	} else {
		if f.MethodHasContext {
			args = append(args, "ctx")
		}
	}

	for _, arg := range f.Args {
		args = append(args, "args["+strconv.Quote(arg.Name)+"].("+templates.CurrentImports.LookupType(arg.TypeReference.GO)+")")
	}

	return strings.Join(args, ", ")
}