go.uber.org/yarpc@v1.72.1/yarpctest/single_use.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package yarpctest
    22  
    23  import "fmt"
    24  
    25  // singleUse is a helper for types that can only be used once.
    26  type singleUse struct{ used bool }
    27  
    28  // ensureUnused panics if this object has already been used.
    29  //
    30  // The argument to this function is used for the error message only.
    31  func (s *singleUse) ensureUnused(o interface{}) {
    32  	if s.used {
    33  		panic(fmt.Sprintf("%v cannot be used again", o))
    34  	}
    35  }
    36  
    37  // use marks this object as used.
    38  //
    39  // It panics if the object was already used. The argument to the function is
    40  // used for the error message.
    41  func (s *singleUse) use(o interface{}) {
    42  	s.ensureUnused(o)
    43  	s.used = true
    44  }