smoke.go

     1  // build -goexperiment arenas
     2  
     3  // Copyright 2023 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  import (
    10  	"arena"
    11  	"log"
    12  	"reflect"
    13  )
    14  
    15  func main() {
    16  	a := arena.NewArena()
    17  	defer a.Free()
    18  
    19  	const iValue = 10
    20  
    21  	i := arena.New[int](a)
    22  	*i = iValue
    23  
    24  	if *i != iValue {
    25  		// This test doesn't reasonably expect this to fail. It's more likely
    26  		// that *i crashes for some reason. Still, why not check it.
    27  		log.Fatalf("bad i value: got %d, want %d", *i, iValue)
    28  	}
    29  
    30  	const wantLen = 125
    31  	const wantCap = 1912
    32  
    33  	sl := arena.MakeSlice[*int](a, wantLen, wantCap)
    34  	if len(sl) != wantLen {
    35  		log.Fatalf("bad arena slice length: got %d, want %d", len(sl), wantLen)
    36  	}
    37  	if cap(sl) != wantCap {
    38  		log.Fatalf("bad arena slice capacity: got %d, want %d", cap(sl), wantCap)
    39  	}
    40  	sl = sl[:cap(sl)]
    41  	for j := range sl {
    42  		sl[j] = i
    43  	}
    44  	for j := range sl {
    45  		if *sl[j] != iValue {
    46  			// This test doesn't reasonably expect this to fail. It's more likely
    47  			// that sl[j] crashes for some reason. Still, why not check it.
    48  			log.Fatalf("bad sl[j] value: got %d, want %d", *sl[j], iValue)
    49  		}
    50  	}
    51  
    52  	t := reflect.TypeOf(int(0))
    53  	v := reflect.ArenaNew(a, t)
    54  	if want := reflect.PointerTo(t); v.Type() != want {
    55  		log.Fatalf("unexpected type for arena-allocated value: got %s, want %s", v.Type(), want)
    56  	}
    57  	i2 := v.Interface().(*int)
    58  	*i2 = iValue
    59  
    60  	if *i2 != iValue {
    61  		// This test doesn't reasonably expect this to fail. It's more likely
    62  		// that *i crashes for some reason. Still, why not check it.
    63  		log.Fatalf("bad i2 value: got %d, want %d", *i2, iValue)
    64  	}
    65  }
    66
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