github.com/prudhvitella/terraform@v0.6.7-0.20151120205041-cf87ede5ddc5/digraph/basic.go (about)

     1  package digraph
     2  
     3  import (
     4  	"fmt"
     5  	"strings"
     6  )
     7  
     8  // BasicNode is a digraph Node that has a name and out edges
     9  type BasicNode struct {
    10  	Name      string
    11  	NodeEdges []Edge
    12  }
    13  
    14  func (b *BasicNode) Edges() []Edge {
    15  	return b.NodeEdges
    16  }
    17  
    18  func (b *BasicNode) AddEdge(edge Edge) {
    19  	b.NodeEdges = append(b.NodeEdges, edge)
    20  }
    21  
    22  func (b *BasicNode) String() string {
    23  	if b.Name == "" {
    24  		return "Node"
    25  	}
    26  	return fmt.Sprintf("%v", b.Name)
    27  }
    28  
    29  // BasicEdge is a digraph Edge that has a name, head and tail
    30  type BasicEdge struct {
    31  	Name     string
    32  	EdgeHead *BasicNode
    33  	EdgeTail *BasicNode
    34  }
    35  
    36  func (b *BasicEdge) Head() Node {
    37  	return b.EdgeHead
    38  }
    39  
    40  // Tail returns the end point of the Edge
    41  func (b *BasicEdge) Tail() Node {
    42  	return b.EdgeTail
    43  }
    44  
    45  func (b *BasicEdge) String() string {
    46  	if b.Name == "" {
    47  		return "Edge"
    48  	}
    49  	return fmt.Sprintf("%v", b.Name)
    50  }
    51  
    52  // ParseBasic is used to parse a string in the format of:
    53  // a -> b ; edge name
    54  // b -> c
    55  // Into a series of basic node and basic edges
    56  func ParseBasic(s string) map[string]*BasicNode {
    57  	lines := strings.Split(s, "\n")
    58  	nodes := make(map[string]*BasicNode)
    59  	for _, line := range lines {
    60  		var edgeName string
    61  		if idx := strings.Index(line, ";"); idx >= 0 {
    62  			edgeName = strings.Trim(line[idx+1:], " \t\r\n")
    63  			line = line[:idx]
    64  		}
    65  		parts := strings.SplitN(line, "->", 2)
    66  		if len(parts) != 2 {
    67  			continue
    68  		}
    69  		head_name := strings.Trim(parts[0], " \t\r\n")
    70  		tail_name := strings.Trim(parts[1], " \t\r\n")
    71  		head := nodes[head_name]
    72  		if head == nil {
    73  			head = &BasicNode{Name: head_name}
    74  			nodes[head_name] = head
    75  		}
    76  		tail := nodes[tail_name]
    77  		if tail == nil {
    78  			tail = &BasicNode{Name: tail_name}
    79  			nodes[tail_name] = tail
    80  		}
    81  		edge := &BasicEdge{
    82  			Name:     edgeName,
    83  			EdgeHead: head,
    84  			EdgeTail: tail,
    85  		}
    86  		head.AddEdge(edge)
    87  	}
    88  	return nodes
    89  }