arn.go

Documentation: github.com/aws/aws-sdk-go-v2/internal/endpoints/awsrulesfn

     1  package awsrulesfn
     2  
     3  import (
     4  	"strings"
     5  )
     6  
     7  // ARN provides AWS ARN components broken out into a data structure.
     8  type ARN struct {
     9  	Partition  string
    10  	Service    string
    11  	Region     string
    12  	AccountId  string
    13  	ResourceId OptionalStringSlice
    14  }
    15  
    16  const (
    17  	arnDelimiters      = ":"
    18  	resourceDelimiters = "/:"
    19  	arnSections        = 6
    20  	arnPrefix          = "arn:"
    21  
    22  	// zero-indexed
    23  	sectionPartition = 1
    24  	sectionService   = 2
    25  	sectionRegion    = 3
    26  	sectionAccountID = 4
    27  	sectionResource  = 5
    28  )
    29  
    30  // ParseARN returns an [ARN] value parsed from the input string provided. If
    31  // the ARN cannot be parsed nil will be returned, and error added to
    32  // [ErrorCollector].
    33  func ParseARN(input string) *ARN {
    34  	if !strings.HasPrefix(input, arnPrefix) {
    35  		return nil
    36  	}
    37  
    38  	sections := strings.SplitN(input, arnDelimiters, arnSections)
    39  	if numSections := len(sections); numSections != arnSections {
    40  		return nil
    41  	}
    42  
    43  	if sections[sectionPartition] == "" {
    44  		return nil
    45  	}
    46  	if sections[sectionService] == "" {
    47  		return nil
    48  	}
    49  	if sections[sectionResource] == "" {
    50  		return nil
    51  	}
    52  
    53  	return &ARN{
    54  		Partition:  sections[sectionPartition],
    55  		Service:    sections[sectionService],
    56  		Region:     sections[sectionRegion],
    57  		AccountId:  sections[sectionAccountID],
    58  		ResourceId: splitResource(sections[sectionResource]),
    59  	}
    60  }
    61  
    62  // splitResource splits the resource components by the ARN resource delimiters.
    63  func splitResource(v string) []string {
    64  	var parts []string
    65  	var offset int
    66  
    67  	for offset <= len(v) {
    68  		idx := strings.IndexAny(v[offset:], "/:")
    69  		if idx < 0 {
    70  			parts = append(parts, v[offset:])
    71  			break
    72  		}
    73  		parts = append(parts, v[offset:idx+offset])
    74  		offset += idx + 1
    75  	}
    76  
    77  	return parts
    78  }
    79  
    80  // OptionalStringSlice provides a helper to safely get the index of a string
    81  // slice that may be out of bounds. Returns pointer to string if index is
    82  // valid. Otherwise returns nil.
    83  type OptionalStringSlice []string
    84  
    85  // Get returns a string pointer of the string at index i if the index is valid.
    86  // Otherwise returns nil.
    87  func (s OptionalStringSlice) Get(i int) *string {
    88  	if i < 0 || i >= len(s) {
    89  		return nil
    90  	}
    91  
    92  	v := s[i]
    93  	return &v
    94  }
    95
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