github.com/wmuizelaar/kpt@v0.0.0-20221018115725-bd564717b2ed/internal/util/stack/stack.go (about)

     1  // Copyright 2019 Google LLC
     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 stack
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/GoogleContainerTools/kpt/internal/pkg"
    21  )
    22  
    23  // New returns a new stack for elements of string type.
    24  func New() *Stack {
    25  	return &Stack{}
    26  }
    27  
    28  type Stack struct {
    29  	slice []string
    30  }
    31  
    32  func (s *Stack) Push(str string) {
    33  	s.slice = append(s.slice, str)
    34  }
    35  
    36  func (s *Stack) Pop() string {
    37  	l := len(s.slice)
    38  	if l == 0 {
    39  		panic(fmt.Errorf("can't pop an empty stack"))
    40  	}
    41  	str := s.slice[l-1]
    42  	s.slice = s.slice[:l-1]
    43  	return str
    44  }
    45  
    46  func (s *Stack) Len() int {
    47  	return len(s.slice)
    48  }
    49  
    50  // NewPkgStack returns a new stack for elements of *pkg.Pkg type.
    51  func NewPkgStack() *PkgStack {
    52  	return &PkgStack{}
    53  }
    54  
    55  type PkgStack struct {
    56  	slice []*pkg.Pkg
    57  }
    58  
    59  func (ps *PkgStack) Push(p *pkg.Pkg) {
    60  	ps.slice = append(ps.slice, p)
    61  }
    62  
    63  func (ps *PkgStack) PushAll(pkgs []*pkg.Pkg) {
    64  	for i := range pkgs {
    65  		p := pkgs[i]
    66  		ps.Push(p)
    67  	}
    68  }
    69  
    70  func (ps *PkgStack) Pop() *pkg.Pkg {
    71  	l := len(ps.slice)
    72  	if l == 0 {
    73  		panic(fmt.Errorf("can't pop an empty stack"))
    74  	}
    75  	p := ps.slice[l-1]
    76  	ps.slice = ps.slice[:l-1]
    77  	return p
    78  }
    79  
    80  func (ps *PkgStack) Len() int {
    81  	return len(ps.slice)
    82  }