-
Notifications
You must be signed in to change notification settings - Fork 190
/
spec.go
503 lines (438 loc) · 11.2 KB
/
spec.go
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
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
package gen
import (
"bytes"
"fmt"
"io"
)
const (
lenAsUint32 = "uint32(len(%s))"
literalFmt = "%s"
intFmt = "%d"
quotedFmt = `"%s"`
mapHeader = "MapHeader"
arrayHeader = "ArrayHeader"
mapKey = "MapKeyPtr"
stringTyp = "String"
u32 = "uint32"
)
// Method is a bitfield representing something that the
// generator knows how to print.
type Method uint8
// are the bits in 'f' set in 'm'?
func (m Method) isset(f Method) bool { return (m&f == f) }
// String implements fmt.Stringer
func (m Method) String() string {
switch m {
case 0, invalidmeth:
return "<invalid method>"
case Decode:
return "decode"
case Encode:
return "encode"
case Marshal:
return "marshal"
case Unmarshal:
return "unmarshal"
case Size:
return "size"
case Test:
return "test"
default:
// return e.g. "decode+encode+test"
modes := [...]Method{Decode, Encode, Marshal, Unmarshal, Size, Test}
any := false
nm := ""
for _, mm := range modes {
if m.isset(mm) {
if any {
nm += "+" + mm.String()
} else {
nm += mm.String()
any = true
}
}
}
return nm
}
}
const (
Decode Method = 1 << iota // msgp.Decodable
Encode // msgp.Encodable
Marshal // msgp.Marshaler
Unmarshal // msgp.Unmarshaler
Size // msgp.Sizer
Test // generate tests
invalidmeth // this isn't a method
encodetest = Encode | Decode | Test // tests for Encodable and Decodable
marshaltest = Marshal | Unmarshal | Test // tests for Marshaler and Unmarshaler
)
type Printer struct {
gens []generator
CompactFloats bool
}
func NewPrinter(m Method, out io.Writer, tests io.Writer) *Printer {
if m.isset(Test) && tests == nil {
panic("cannot print tests with 'nil' tests argument!")
}
gens := make([]generator, 0, 7)
if m.isset(Decode) {
gens = append(gens, decode(out))
}
if m.isset(Encode) {
gens = append(gens, encode(out))
}
if m.isset(Marshal) {
gens = append(gens, marshal(out))
}
if m.isset(Unmarshal) {
gens = append(gens, unmarshal(out))
}
if m.isset(Size) {
gens = append(gens, sizes(out))
}
if m.isset(marshaltest) {
gens = append(gens, mtest(tests))
}
if m.isset(encodetest) {
gens = append(gens, etest(tests))
}
if len(gens) == 0 {
panic("NewPrinter called with invalid method flags")
}
return &Printer{gens: gens}
}
// TransformPass is a pass that transforms individual
// elements. (Note that if the returned is different from
// the argument, it should not point to the same objects.)
type TransformPass func(Elem) Elem
// IgnoreTypename is a pass that just ignores
// types of a given name.
func IgnoreTypename(name string) TransformPass {
return func(e Elem) Elem {
if e.TypeName() == name {
return nil
}
return e
}
}
// ApplyDirective applies a directive to a named pass
// and all of its dependents.
func (p *Printer) ApplyDirective(pass Method, t TransformPass) {
for _, g := range p.gens {
if g.Method().isset(pass) {
g.Add(t)
}
}
}
// Print prints an Elem.
func (p *Printer) Print(e Elem) error {
for _, g := range p.gens {
// Elem.SetVarname() is called before the Print() step in parse.FileSet.PrintTo().
// Elem.SetVarname() generates identifiers as it walks the Elem. This can cause
// collisions between idents created during SetVarname and idents created during Print,
// hence the separate prefixes.
resetIdent("zb")
err := g.Execute(e, Context{compFloats: p.CompactFloats})
resetIdent("za")
if err != nil {
return err
}
}
return nil
}
type contextItem interface {
Arg() string
}
type contextString string
func (c contextString) Arg() string {
return fmt.Sprintf("%q", c)
}
type contextVar string
func (c contextVar) Arg() string {
return string(c)
}
type Context struct {
path []contextItem
compFloats bool
}
func (c *Context) PushString(s string) {
c.path = append(c.path, contextString(s))
}
func (c *Context) PushVar(s string) {
c.path = append(c.path, contextVar(s))
}
func (c *Context) Pop() {
c.path = c.path[:len(c.path)-1]
}
func (c *Context) ArgsStr() string {
var out string
for idx, p := range c.path {
if idx > 0 {
out += ", "
}
out += p.Arg()
}
return out
}
// generator is the interface through
// which code is generated.
type generator interface {
Method() Method
Add(p TransformPass)
Execute(Elem, Context) error // execute writes the method for the provided object.
}
type passes []TransformPass
func (p *passes) Add(t TransformPass) {
*p = append(*p, t)
}
func (p *passes) applyall(e Elem) Elem {
for _, t := range *p {
e = t(e)
if e == nil {
return nil
}
}
return e
}
type traversal interface {
gMap(*Map)
gSlice(*Slice)
gArray(*Array)
gPtr(*Ptr)
gBase(*BaseElem)
gStruct(*Struct)
}
// type-switch dispatch to the correct
// method given the type of 'e'
func next(t traversal, e Elem) {
switch e := e.(type) {
case *Map:
t.gMap(e)
case *Struct:
t.gStruct(e)
case *Slice:
t.gSlice(e)
case *Array:
t.gArray(e)
case *Ptr:
t.gPtr(e)
case *BaseElem:
t.gBase(e)
default:
panic("bad element type")
}
}
// possibly-immutable method receiver
func imutMethodReceiver(p Elem) string {
switch e := p.(type) {
case *Struct:
// TODO(HACK): actually do real math here.
if len(e.Fields) <= 3 {
for i := range e.Fields {
if be, ok := e.Fields[i].FieldElem.(*BaseElem); !ok || (be.Value == IDENT || be.Value == Bytes) {
goto nope
}
}
return p.TypeName()
}
nope:
return "*" + p.TypeName()
// gets dereferenced automatically
case *Array:
return "*" + p.TypeName()
// everything else can be
// by-value.
default:
return p.TypeName()
}
}
// if necessary, wraps a type
// so that its method receiver
// is of the write type.
func methodReceiver(p Elem) string {
switch p.(type) {
// structs and arrays are
// dereferenced automatically,
// so no need to alter varname
case *Struct, *Array:
return "*" + p.TypeName()
// set variable name to
// *varname
default:
p.SetVarname("(*" + p.Varname() + ")")
return "*" + p.TypeName()
}
}
func unsetReceiver(p Elem) {
switch p.(type) {
case *Struct, *Array:
default:
p.SetVarname("z")
}
}
// shared utility for generators
type printer struct {
w io.Writer
err error
}
// writes "var {{name}} {{typ}};"
func (p *printer) declare(name string, typ string) {
p.printf("\nvar %s %s", name, typ)
}
// does:
//
// if m == nil {
// m = make(type, size)
// } else if len(m) > 0 {
//
// for key := range m { delete(m, key) }
// }
func (p *printer) resizeMap(size string, m *Map) {
vn := m.Varname()
if !p.ok() {
return
}
p.printf("\nif %s == nil {", vn)
p.printf("\n%s = make(%s, %s)", vn, m.TypeName(), size)
p.printf("\n} else if len(%s) > 0 {", vn)
p.clearMap(vn)
p.closeblock()
}
// assign key to value based on varnames
func (p *printer) mapAssign(m *Map) {
if !p.ok() {
return
}
p.printf("\n%s[%s] = %s", m.Varname(), m.Keyidx, m.Validx)
}
// clear map keys
func (p *printer) clearMap(name string) {
p.printf("\nfor key := range %[1]s { delete(%[1]s, key) }", name)
}
func (p *printer) wrapErrCheck(ctx string) {
p.print("\nif err != nil {")
p.printf("\nerr = msgp.WrapError(err, %s)", ctx)
p.printf("\nreturn")
p.print("\n}")
}
func (p *printer) resizeSlice(size string, s *Slice) {
p.printf("\nif cap(%[1]s) >= int(%[2]s) { %[1]s = (%[1]s)[:%[2]s] } else { %[1]s = make(%[3]s, %[2]s) }", s.Varname(), size, s.TypeName())
}
// resizeSliceNoNil will resize a slice and will not allow nil slices.
func (p *printer) resizeSliceNoNil(size string, s *Slice) {
p.printf("\nif %[1]s != nil && cap(%[1]s) >= int(%[2]s) {", s.Varname(), size)
p.printf("\n%[1]s = (%[1]s)[:%[2]s]", s.Varname(), size)
p.printf("\n} else { %[1]s = make(%[3]s, %[2]s) }", s.Varname(), size, s.TypeName())
}
func (p *printer) arrayCheck(want string, got string) {
p.printf("\nif %[1]s != %[2]s { err = msgp.ArrayError{Wanted: %[2]s, Got: %[1]s}; return }", got, want)
}
func (p *printer) closeblock() { p.print("\n}") }
// does:
//
// for idx := range iter {
// {{generate inner}}
// }
func (p *printer) rangeBlock(ctx *Context, idx string, iter string, t traversal, inner Elem) {
ctx.PushVar(idx)
p.printf("\n for %s := range %s {", idx, iter)
next(t, inner)
p.closeblock()
ctx.Pop()
}
func (p *printer) nakedReturn() {
if p.ok() {
p.print("\nreturn\n}\n")
}
}
func (p *printer) comment(s string) {
p.print("\n// " + s)
}
func (p *printer) printf(format string, args ...interface{}) {
if p.err == nil {
_, p.err = fmt.Fprintf(p.w, format, args...)
}
}
func (p *printer) print(format string) {
if p.err == nil {
_, p.err = io.WriteString(p.w, format)
}
}
func (p *printer) initPtr(pt *Ptr) {
if pt.Needsinit() {
vname := pt.Varname()
p.printf("\nif %s == nil { %s = new(%s); }", vname, vname, pt.Value.TypeName())
}
}
func (p *printer) ok() bool { return p.err == nil }
func tobaseConvert(b *BaseElem) string {
return b.ToBase() + "(" + b.Varname() + ")"
}
func (p *printer) varWriteMapHeader(receiver string, sizeVarname string, maxSize int) {
if maxSize <= 15 {
p.printf("\nerr = %s.Append(0x80 | uint8(%s))", receiver, sizeVarname)
} else {
p.printf("\nerr = %s.WriteMapHeader(%s)", receiver, sizeVarname)
}
}
func (p *printer) varAppendMapHeader(sliceVarname string, sizeVarname string, maxSize int) {
if maxSize <= 15 {
p.printf("\n%s = append(%s, 0x80 | uint8(%s))", sliceVarname, sliceVarname, sizeVarname)
} else {
p.printf("\n%s = msgp.AppendMapHeader(%s, %s)", sliceVarname, sliceVarname, sizeVarname)
}
}
// bmask is a bitmask of a the specified number of bits
type bmask struct {
bitlen int
varname string
}
// typeDecl returns the variable declaration as a var statement
func (b *bmask) typeDecl() string {
return fmt.Sprintf("var %s %s /* %d bits */", b.varname, b.typeName(), b.bitlen)
}
// typeName returns the type, e.g. "uint8" or "[2]uint64"
func (b *bmask) typeName() string {
if b.bitlen <= 8 {
return "uint8"
}
if b.bitlen <= 16 {
return "uint16"
}
if b.bitlen <= 32 {
return "uint32"
}
if b.bitlen <= 64 {
return "uint64"
}
return fmt.Sprintf("[%d]uint64", (b.bitlen+64-1)/64)
}
// readExpr returns the expression to read from a position in the bitmask.
// Compare ==0 for false or !=0 for true.
func (b *bmask) readExpr(bitoffset int) string {
if bitoffset < 0 || bitoffset >= b.bitlen {
panic(fmt.Errorf("bitoffset %d out of range for bitlen %d", bitoffset, b.bitlen))
}
var buf bytes.Buffer
buf.Grow(len(b.varname) + 16)
buf.WriteByte('(')
buf.WriteString(b.varname)
if b.bitlen > 64 {
fmt.Fprintf(&buf, "[%d]", (bitoffset / 64))
}
buf.WriteByte('&')
fmt.Fprintf(&buf, "0x%X", (uint64(1) << (uint64(bitoffset) % 64)))
buf.WriteByte(')')
return buf.String()
}
// setStmt returns the statement to set the specified bit in the bitmask.
func (b *bmask) setStmt(bitoffset int) string {
var buf bytes.Buffer
buf.Grow(len(b.varname) + 16)
buf.WriteString(b.varname)
if b.bitlen > 64 {
fmt.Fprintf(&buf, "[%d]", (bitoffset / 64))
}
fmt.Fprintf(&buf, " |= 0x%X", (uint64(1) << (uint64(bitoffset) % 64)))
return buf.String()
}