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tree_ls.go
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tree_ls.go
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package gitfmt
import (
"errors"
"fmt"
"strings"
"github.com/bitwormhole/gitlib/git"
)
// FormatTree ...
func FormatTree(tree *git.Tree) ([]byte, error) {
tf := treeFormatter{}
return tf.format(tree)
}
// ParseTree ...
func ParseTree(data []byte) (*git.Tree, error) {
tp := treeReader{}
tp.init(data)
return tp.readAll()
}
////////////////////////////////////////////////////////////////////////////////
type treeFormatter struct{}
func (inst *treeFormatter) format(tree *git.Tree) ([]byte, error) {
return nil, errors.New("no impl")
}
////////////////////////////////////////////////////////////////////////////////
type treeReader struct {
data []byte
pos int
end int
idSize int // in bytes
}
func (inst *treeReader) init(data []byte) {
if data == nil {
data = []byte{}
}
inst.data = data
inst.pos = 0
inst.end = len(data)
}
func (inst *treeReader) readAll() (*git.Tree, error) {
tree := &git.Tree{}
for !inst.isEOF() {
item := &git.TreeItem{}
err := inst.readItem(item)
if err != nil {
return nil, err
}
tree.Items = append(tree.Items, item)
}
return tree, nil
}
func (inst *treeReader) isEOF() bool {
return inst.end <= inst.pos
}
func (inst *treeReader) readItem(dst *git.TreeItem) error {
err := inst.readItemHead(dst)
if err != nil {
return err
}
return inst.readItemID(dst)
}
func (inst *treeReader) readItemHead(dst *git.TreeItem) error {
i0 := inst.pos // the begin of item
i1 := i0 // the SPACE gap between mode & name
i2 := i0 // end of head, '\0'
end := inst.end
data := inst.data
for i := i1; i < end; i++ {
b := data[i]
if b == 0 {
i2 = i
break
} else if b == ' ' && i1 == i0 {
i1 = i
}
}
if i0 < i1 && i1 < i2 && i2 < end {
mode := data[i0:i1]
name := data[i1+1 : i2]
dst.Mode = inst.parseItemMode(mode)
dst.Name = string(name)
} else {
return fmt.Errorf("bad tree item head")
}
inst.pos = i2 + 1
inst.idSize = 20 // 20(bytes) = 160(bits)
return nil
}
func (inst *treeReader) parseItemMode(data []byte) git.TreeItemMode {
str := string(data)
str = strings.TrimSpace(str)
return git.TreeItemMode(str)
}
func (inst *treeReader) readItemID(dst *git.TreeItem) error {
i1 := inst.pos
i2 := inst.pos + inst.idSize
if 0 < i1 && i1 < i2 && i2 <= inst.end {
// continue
} else {
return fmt.Errorf("EOF with exception")
}
idData := inst.data[i1:i2]
id, err := CreateObjectID(idData)
if err != nil {
return err
}
dst.ID = id
inst.pos = i2
return nil
}
////////////////////////////////////////////////////////////////////////////////