/
base.go
180 lines (162 loc) · 3.64 KB
/
base.go
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package main
import (
"compress/bzip2"
"compress/gzip"
"errors"
"fmt"
"io"
"net/url"
"os"
"path"
"github.com/nightlyone/deb/diff"
"github.com/nightlyone/deb/repository"
)
// Base is a base for futher repository retrieval actions
type Base struct {
u *url.URL
fs FileSystem
tag string
}
// NewBase creates a base for further repository retrieval actions
func NewBase(base string, tag string) (*Base, error) {
if base == "." || base == "" {
pwd, err := os.Getwd()
if err != nil {
return nil, err
}
base = pwd
}
u, err := url.Parse(base)
if err != nil {
return nil, err
}
if u.Fragment != "" {
return nil, fmt.Errorf("invalid url %q, fragments are not supported", base)
}
// Need to parse a second time, bacause we want it absolute, but url.ParseRequestURI supports no fragments
u, err = url.ParseRequestURI(base)
if err != nil {
return nil, err
}
if u.RawQuery != "" {
return nil, fmt.Errorf("invalid url %q, query parameters are not supported", base)
}
u, _ = u.Parse(u.Path)
switch u.Scheme {
case "":
u.Scheme = "file"
fallthrough
case "file":
return &Base{
u: u,
fs: LocalDir(u.Path),
tag: tag,
}, nil
case "http", "https":
if u.Host == "" {
return nil, fmt.Errorf("invalid remote url %q, host part should not be empty", base)
}
if tag != "" {
u.Host = tag + "." + u.Host
}
return &Base{
u: u,
fs: WebDir(u.String()),
}, nil
default:
return nil, fmt.Errorf("invalid url %q, scheme %q not supported (only file://)", base, u.Scheme)
}
}
func (b *Base) taggedRepository(r *repository.Repository) *repository.Repository {
rep := *r
rep.DebMirrorTag = b.tag
return &rep
}
func readList(r io.ReadCloser, ext string) (list *diff.List, err error) {
var reader io.Reader
defer r.Close()
switch ext {
case ".gz":
reader, err = gzip.NewReader(r)
if err != nil {
return
}
defer reader.(io.Closer).Close()
case ".bz2":
reader = bzip2.NewReader(r)
case "":
reader = r
}
return diff.NewList(reader)
}
func (b *Base) loadMergableLists(mergable []string) (combined *diff.List, err error) {
lists := map[string]*diff.List{}
for _, fn := range mergable {
key := path.Join(path.Dir(fn), "Packages")
list := lists[key]
if list != nil {
continue
}
f, err := b.fs.Open(fn)
if err != nil {
return nil, err
}
list, err = readList(f, path.Ext(fn))
if err != nil {
return nil, err
}
lists[key] = list
}
for _, v := range lists {
if combined == nil {
combined = v
} else {
combined.Merge(v)
}
}
return
}
func (b *Base) Packages(repo *repository.Repository) (combined map[string]*diff.List, err error) {
tagged := b.taggedRepository(repo)
combined = map[string]*diff.List{}
for key, mergable := range tagged.KeySets() {
c, err := b.loadMergableLists(mergable)
if err != nil {
return nil, err
}
combined[key] = c
}
return combined, nil
}
type Changeset struct {
Added []*diff.Package `json:",omitempty"`
Removed []*diff.Package `json:",omitempty"`
Updated []*diff.Update `json:",omitempty"`
}
var errIncompatible = errors.New("Incompatible package lists")
func CalcUpdates(newer, older *Base, repo *repository.Repository) (map[string]Changeset, error) {
o, err := older.Packages(repo)
if err != nil {
return nil, err
}
n, err := newer.Packages(repo)
if err != nil {
return nil, err
}
if len(n) != len(o) {
return nil, errIncompatible
}
changes := map[string]Changeset{}
for key, list := range n {
a, r, u := diff.Changes(list, o[key])
if len(a) == 0 && len(r) == 0 && len(u) == 0 {
continue
}
changes[key] = Changeset{
Added: a,
Removed: r,
Updated: diff.CompressUpdates(u),
}
}
return changes, nil
}