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      1 // Copyright 2015 Google Inc. All rights reserved
      2 //
      3 // Licensed under the Apache License, Version 2.0 (the "License");
      4 // you may not use this file except in compliance with the License.
      5 // You may obtain a copy of the License at
      6 //
      7 //      http://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 // Unless required by applicable law or agreed to in writing, software
     10 // distributed under the License is distributed on an "AS IS" BASIS,
     11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 // See the License for the specific language governing permissions and
     13 // limitations under the License.
     14 
     15 package kati
     16 
     17 import (
     18 	"bytes"
     19 	"fmt"
     20 	"io"
     21 	"strings"
     22 )
     23 
     24 // Var is an interface of make variable.
     25 type Var interface {
     26 	Value
     27 	Append(*Evaluator, string) (Var, error)
     28 	AppendVar(*Evaluator, Value) (Var, error)
     29 	Flavor() string
     30 	Origin() string
     31 	IsDefined() bool
     32 }
     33 
     34 type targetSpecificVar struct {
     35 	v  Var
     36 	op string
     37 }
     38 
     39 func (v *targetSpecificVar) Append(ev *Evaluator, s string) (Var, error) {
     40 	nv, err := v.v.Append(ev, s)
     41 	if err != nil {
     42 		return nil, err
     43 	}
     44 	return &targetSpecificVar{
     45 		v:  nv,
     46 		op: v.op,
     47 	}, nil
     48 }
     49 func (v *targetSpecificVar) AppendVar(ev *Evaluator, v2 Value) (Var, error) {
     50 	nv, err := v.v.AppendVar(ev, v2)
     51 	if err != nil {
     52 		return nil, err
     53 	}
     54 	return &targetSpecificVar{
     55 		v:  nv,
     56 		op: v.op,
     57 	}, nil
     58 }
     59 func (v *targetSpecificVar) Flavor() string {
     60 	return v.v.Flavor()
     61 }
     62 func (v *targetSpecificVar) Origin() string {
     63 	return v.v.Origin()
     64 }
     65 func (v *targetSpecificVar) IsDefined() bool {
     66 	return v.v.IsDefined()
     67 }
     68 func (v *targetSpecificVar) String() string {
     69 	// TODO: If we add the info of |op| a test starts
     70 	// failing. Shouldn't we use this only for debugging?
     71 	return v.v.String()
     72 	// return v.v.String() + " (op=" + v.op + ")"
     73 }
     74 func (v *targetSpecificVar) Eval(w evalWriter, ev *Evaluator) error {
     75 	return v.v.Eval(w, ev)
     76 }
     77 
     78 func (v *targetSpecificVar) serialize() serializableVar {
     79 	return serializableVar{
     80 		Type:     v.op,
     81 		Children: []serializableVar{v.v.serialize()},
     82 	}
     83 }
     84 
     85 func (v *targetSpecificVar) dump(d *dumpbuf) {
     86 	d.Byte(valueTypeTSV)
     87 	d.Str(v.op)
     88 	v.v.dump(d)
     89 }
     90 
     91 type simpleVar struct {
     92 	// space separated. note that each string may contain spaces, so
     93 	// it is not word list.
     94 	value  []string
     95 	origin string
     96 }
     97 
     98 func (v *simpleVar) Flavor() string  { return "simple" }
     99 func (v *simpleVar) Origin() string  { return v.origin }
    100 func (v *simpleVar) IsDefined() bool { return true }
    101 
    102 func (v *simpleVar) String() string { return strings.Join(v.value, " ") }
    103 func (v *simpleVar) Eval(w evalWriter, ev *Evaluator) error {
    104 	space := false
    105 	for _, v := range v.value {
    106 		if space {
    107 			writeByte(w, ' ')
    108 		}
    109 		io.WriteString(w, v)
    110 		space = true
    111 	}
    112 	return nil
    113 }
    114 func (v *simpleVar) serialize() serializableVar {
    115 	return serializableVar{
    116 		Type:   "simple",
    117 		V:      v.String(),
    118 		Origin: v.origin,
    119 	}
    120 }
    121 func (v *simpleVar) dump(d *dumpbuf) {
    122 	d.Byte(valueTypeSimple)
    123 	d.Int(len(v.value))
    124 	for _, v := range v.value {
    125 		d.Str(v)
    126 	}
    127 	d.Str(v.origin)
    128 }
    129 
    130 func (v *simpleVar) Append(ev *Evaluator, s string) (Var, error) {
    131 	val, _, err := parseExpr([]byte(s), nil, parseOp{})
    132 	if err != nil {
    133 		return nil, err
    134 	}
    135 	abuf := newEbuf()
    136 	err = val.Eval(abuf, ev)
    137 	if err != nil {
    138 		return nil, err
    139 	}
    140 	v.value = append(v.value, abuf.String())
    141 	abuf.release()
    142 	return v, nil
    143 }
    144 
    145 func (v *simpleVar) AppendVar(ev *Evaluator, val Value) (Var, error) {
    146 	abuf := newEbuf()
    147 	err := val.Eval(abuf, ev)
    148 	if err != nil {
    149 		return nil, err
    150 	}
    151 	v.value = append(v.value, abuf.String())
    152 	abuf.release()
    153 	return v, nil
    154 }
    155 
    156 type automaticVar struct {
    157 	value []byte
    158 }
    159 
    160 func (v *automaticVar) Flavor() string  { return "simple" }
    161 func (v *automaticVar) Origin() string  { return "automatic" }
    162 func (v *automaticVar) IsDefined() bool { return true }
    163 
    164 func (v *automaticVar) String() string { return string(v.value) }
    165 func (v *automaticVar) Eval(w evalWriter, ev *Evaluator) error {
    166 	w.Write(v.value)
    167 	return nil
    168 }
    169 func (v *automaticVar) serialize() serializableVar {
    170 	return serializableVar{Type: ""}
    171 }
    172 func (v *automaticVar) dump(d *dumpbuf) {
    173 	d.err = fmt.Errorf("cannnot dump automatic var:%s", v.value)
    174 }
    175 
    176 func (v *automaticVar) Append(ev *Evaluator, s string) (Var, error) {
    177 	val, _, err := parseExpr([]byte(s), nil, parseOp{})
    178 	if err != nil {
    179 		return nil, err
    180 	}
    181 	abuf := newEbuf()
    182 	err = val.Eval(abuf, ev)
    183 	if err != nil {
    184 		return nil, err
    185 	}
    186 	value := []string{string(v.value), abuf.String()}
    187 	abuf.release()
    188 	return &simpleVar{
    189 		value:  value,
    190 		origin: "file",
    191 	}, nil
    192 }
    193 
    194 func (v *automaticVar) AppendVar(ev *Evaluator, val Value) (Var, error) {
    195 	abuf := newEbuf()
    196 	err := val.Eval(abuf, ev)
    197 	if err != nil {
    198 		return nil, err
    199 	}
    200 	value := []string{string(v.value), abuf.String()}
    201 	abuf.release()
    202 	return &simpleVar{
    203 		value:  value,
    204 		origin: "file",
    205 	}, nil
    206 }
    207 
    208 type recursiveVar struct {
    209 	expr   Value
    210 	origin string
    211 }
    212 
    213 func (v *recursiveVar) Flavor() string  { return "recursive" }
    214 func (v *recursiveVar) Origin() string  { return v.origin }
    215 func (v *recursiveVar) IsDefined() bool { return true }
    216 
    217 func (v *recursiveVar) String() string { return v.expr.String() }
    218 func (v *recursiveVar) Eval(w evalWriter, ev *Evaluator) error {
    219 	v.expr.Eval(w, ev)
    220 	return nil
    221 }
    222 func (v *recursiveVar) serialize() serializableVar {
    223 	return serializableVar{
    224 		Type:     "recursive",
    225 		Children: []serializableVar{v.expr.serialize()},
    226 		Origin:   v.origin,
    227 	}
    228 }
    229 func (v *recursiveVar) dump(d *dumpbuf) {
    230 	d.Byte(valueTypeRecursive)
    231 	v.expr.dump(d)
    232 	d.Str(v.origin)
    233 }
    234 
    235 func (v *recursiveVar) Append(_ *Evaluator, s string) (Var, error) {
    236 	var exp expr
    237 	if e, ok := v.expr.(expr); ok {
    238 		exp = append(e, literal(" "))
    239 	} else {
    240 		exp = expr{v.expr, literal(" ")}
    241 	}
    242 	sv, _, err := parseExpr([]byte(s), nil, parseOp{alloc: true})
    243 	if err != nil {
    244 		return nil, err
    245 	}
    246 	if aexpr, ok := sv.(expr); ok {
    247 		exp = append(exp, aexpr...)
    248 	} else {
    249 		exp = append(exp, sv)
    250 	}
    251 	v.expr = exp
    252 	return v, nil
    253 }
    254 
    255 func (v *recursiveVar) AppendVar(ev *Evaluator, val Value) (Var, error) {
    256 	var buf bytes.Buffer
    257 	buf.WriteString(v.expr.String())
    258 	buf.WriteByte(' ')
    259 	buf.WriteString(val.String())
    260 	e, _, err := parseExpr(buf.Bytes(), nil, parseOp{alloc: true})
    261 	if err != nil {
    262 		return nil, err
    263 	}
    264 	v.expr = e
    265 	return v, nil
    266 }
    267 
    268 type undefinedVar struct{}
    269 
    270 func (undefinedVar) Flavor() string  { return "undefined" }
    271 func (undefinedVar) Origin() string  { return "undefined" }
    272 func (undefinedVar) IsDefined() bool { return false }
    273 func (undefinedVar) String() string  { return "" }
    274 func (undefinedVar) Eval(_ evalWriter, _ *Evaluator) error {
    275 	return nil
    276 }
    277 func (undefinedVar) serialize() serializableVar {
    278 	return serializableVar{Type: "undefined"}
    279 }
    280 func (undefinedVar) dump(d *dumpbuf) {
    281 	d.Byte(valueTypeUndefined)
    282 }
    283 
    284 func (undefinedVar) Append(*Evaluator, string) (Var, error) {
    285 	return undefinedVar{}, nil
    286 }
    287 
    288 func (undefinedVar) AppendVar(_ *Evaluator, val Value) (Var, error) {
    289 	return undefinedVar{}, nil
    290 }
    291 
    292 // Vars is a map for make variables.
    293 type Vars map[string]Var
    294 
    295 // usedEnvs tracks what environment variables are used.
    296 var usedEnvs = map[string]bool{}
    297 
    298 // Lookup looks up named make variable.
    299 func (vt Vars) Lookup(name string) Var {
    300 	if v, ok := vt[name]; ok {
    301 		if strings.HasPrefix(v.Origin(), "environment") {
    302 			usedEnvs[name] = true
    303 		}
    304 		return v
    305 	}
    306 	return undefinedVar{}
    307 }
    308 
    309 // origin precedence
    310 //  override / environment override
    311 //  command line
    312 //  file
    313 //  environment
    314 //  default
    315 // TODO(ukai): is this correct order?
    316 var originPrecedence = map[string]int{
    317 	"override":             4,
    318 	"environment override": 4,
    319 	"command line":         3,
    320 	"file":                 2,
    321 	"environment":          2,
    322 	"default":              1,
    323 	"undefined":            0,
    324 	"automatic":            0,
    325 }
    326 
    327 // Assign assigns v to name.
    328 func (vt Vars) Assign(name string, v Var) {
    329 	vo := v.Origin()
    330 	// assign automatic always win.
    331 	// assign new value to automatic always win.
    332 	if vo != "automatic" {
    333 		vp := originPrecedence[v.Origin()]
    334 		var op int
    335 		if ov, ok := vt[name]; ok {
    336 			op = originPrecedence[ov.Origin()]
    337 		}
    338 		if op > vp {
    339 			return
    340 		}
    341 	}
    342 	vt[name] = v
    343 }
    344 
    345 // NewVars creates new Vars.
    346 func NewVars(vt Vars) Vars {
    347 	r := make(Vars)
    348 	r.Merge(vt)
    349 	return r
    350 }
    351 
    352 // Merge merges vt2 into vt.
    353 func (vt Vars) Merge(vt2 Vars) {
    354 	for k, v := range vt2 {
    355 		vt[k] = v
    356 	}
    357 }
    358 
    359 // save saves value of the variable named name.
    360 // calling returned value will restore to the old value at the time
    361 // when save called.
    362 func (vt Vars) save(name string) func() {
    363 	if v, ok := vt[name]; ok {
    364 		return func() {
    365 			vt[name] = v
    366 		}
    367 	}
    368 	return func() {
    369 		delete(vt, name)
    370 	}
    371 }
    372