terraform/command/hcl_printer.go

197 lines
3.6 KiB
Go

package command
// Marshal an object as an hcl value.
import (
"bytes"
"fmt"
"regexp"
"github.com/hashicorp/hcl/hcl/printer"
)
// This will only work operate on []interface{}, map[string]interface{}, and
// primitive types.
func encodeHCL(i interface{}) ([]byte, error) {
state := &encodeState{}
err := state.encode(i)
if err != nil {
return nil, err
}
hcl := state.Bytes()
if len(hcl) == 0 {
return hcl, nil
}
// the HCL parser requires an assignment. Strip it off again later
fakeAssignment := append([]byte("X = "), hcl...)
// use the real hcl parser to verify our output, and format it canonically
hcl, err = printer.Format(fakeAssignment)
if err != nil {
return nil, err
}
// now strip that first assignment off
eq := regexp.MustCompile(`=\s+`).FindIndex(hcl)
// strip of an extra \n if it's there
end := len(hcl)
if hcl[end-1] == '\n' {
end -= 1
}
return hcl[eq[1]:end], nil
}
type encodeState struct {
bytes.Buffer
}
func (e *encodeState) encode(i interface{}) error {
switch v := i.(type) {
case []interface{}:
return e.encodeList(v)
case map[string]interface{}:
return e.encodeMap(v)
case int, int8, int32, int64, uint8, uint32, uint64:
return e.encodeInt(i)
case float32, float64:
return e.encodeFloat(i)
case string:
return e.encodeString(v)
case nil:
return nil
default:
return fmt.Errorf("invalid type %T", i)
}
}
func (e *encodeState) encodeList(l []interface{}) error {
e.WriteString("[")
for i, v := range l {
err := e.encode(v)
if err != nil {
return err
}
if i < len(l)-1 {
e.WriteString(", ")
}
}
e.WriteString("]")
return nil
}
func (e *encodeState) encodeMap(m map[string]interface{}) error {
e.WriteString("{\n")
for i, k := range sortedKeys(m) {
v := m[k]
e.WriteString(k + " = ")
err := e.encode(v)
if err != nil {
return err
}
if i < len(m)-1 {
e.WriteString("\n")
}
}
e.WriteString("}")
return nil
}
func (e *encodeState) encodeInt(i interface{}) error {
_, err := fmt.Fprintf(e, "%d", i)
return err
}
func (e *encodeState) encodeFloat(f interface{}) error {
_, err := fmt.Fprintf(e, "%g", f)
return err
}
func (e *encodeState) encodeString(s string) error {
e.Write(quoteHCLString(s))
return nil
}
// Quote an HCL string, which may contain interpolations.
// Since the string was already parsed from HCL, we have to assume the
// required characters are sanely escaped. All we need to do is escape double
// quotes in the string, unless they are in an interpolation block.
func quoteHCLString(s string) []byte {
out := make([]byte, 0, len(s))
out = append(out, '"')
// our parse states
var (
outer = 1 // the starting state for the string
dollar = 2 // look for '{' in the next character
interp = 3 // inside an interpolation block
escape = 4 // take the next character and pop back to prev state
)
// we could have nested interpolations
state := stack{}
state.push(outer)
for i := 0; i < len(s); i++ {
switch state.peek() {
case outer:
switch s[i] {
case '"':
out = append(out, '\\')
case '$':
state.push(dollar)
case '\\':
state.push(escape)
}
case dollar:
state.pop()
switch s[i] {
case '{':
state.push(interp)
case '\\':
state.push(escape)
}
case interp:
switch s[i] {
case '}':
state.pop()
}
case escape:
state.pop()
}
out = append(out, s[i])
}
out = append(out, '"')
return out
}
type stack []int
func (s *stack) push(i int) {
*s = append(*s, i)
}
func (s *stack) pop() int {
last := len(*s) - 1
i := (*s)[last]
*s = (*s)[:last]
return i
}
func (s *stack) peek() int {
return (*s)[len(*s)-1]
}