Files
kitty/kittens/choose_files/calibre.go
Kovid Goyal 0c4cefd720 Fully fix flicker on first use of calibre preview backend
Also show the user the error from the calibre backend, if any
2025-11-23 12:39:30 +05:30

248 lines
6.8 KiB
Go

package choose_files
import (
"bufio"
"encoding/json"
"errors"
"fmt"
"io"
"io/fs"
"os"
"os/exec"
"path/filepath"
"slices"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/kovidgoyal/kitty/tools/icons"
"github.com/kovidgoyal/kitty/tools/utils"
"github.com/kovidgoyal/kitty/tools/utils/humanize"
"github.com/kovidgoyal/kitty/tools/utils/images"
"golang.org/x/sys/unix"
)
var _ = fmt.Print
var calibre_needs_cleanup atomic.Bool
var calibre_server_load_finished atomic.Bool
type calibre_server_process struct {
proc *exec.Cmd
stdout io.ReadCloser
stdin io.WriteCloser
file_extensions *utils.Set[string]
}
type CalibreMetadata struct {
Title string `json:"title"`
Authors []string `json:"authors"`
Series string `json:"series"`
Series_index float64 `json:"series_index"`
Tags []string `json:"tags"`
Rating float64 `json:"rating"`
Published time.Time `json:"pubdate"`
Timestamp time.Time `json:"timestamp"`
}
type CalibreResponse struct {
Path string `json:"path"`
Filetypes []string `json:"filetypes"`
Cover string `json:"cover"`
Error string `json:"error"`
Metadata CalibreMetadata `json:"metadata"`
}
func ReadLineWithTimeout(r io.Reader, timeout time.Duration) (string, error) {
type result struct {
line string
err error
}
ch := make(chan result, 1)
go func() {
br := bufio.NewReader(r)
line, err := br.ReadString('\n')
ch <- result{strings.TrimRight(line, "\n"), err}
}()
select {
case res := <-ch:
return res.line, res.err
case <-time.After(timeout):
return "", os.ErrDeadlineExceeded
}
}
var calibre_server = sync.OnceValues(func() (ans *calibre_server_process, err error) {
defer func() { calibre_server_load_finished.Store(true) }()
ans = &calibre_server_process{}
ans.proc = exec.Command("calibre-debug", "-c", "from calibre.ebooks.metadata.cli import *; simple_metadata_server()")
ans.proc.Stderr = nil
if ans.stdout, err = ans.proc.StdoutPipe(); err != nil {
return nil, err
}
if ans.stdin, err = ans.proc.StdinPipe(); err != nil {
ans.stdout.Close()
return nil, err
}
ans.proc.SysProcAttr = &unix.SysProcAttr{Setsid: true}
if err = ans.proc.Start(); err != nil {
err = fmt.Errorf("calibre-debug executable not found in PATH, you must install the calibre program to preview these file types: %w", err)
return
}
calibre_needs_cleanup.Store(true)
payload, _ := json.Marshal(map[string]string{"path": ""})
if _, err = ans.stdin.Write(append(payload, '\n')); err != nil {
err = fmt.Errorf("error writing to calibre metadata server: %w", err)
return
}
line, err := ReadLineWithTimeout(ans.stdout, 2*time.Second)
if err != nil {
if errors.Is(err, os.ErrDeadlineExceeded) {
err = fmt.Errorf("timed out waiting for response from calibre metadata server, make sure you are using calibre version >= 8.16")
} else {
err = fmt.Errorf("error reading from calibre metadata server: %w", err)
}
return
}
var r CalibreResponse
if err = json.Unmarshal([]byte(line), &r); err != nil {
err = fmt.Errorf("unexpected response from calibre metadata server: %#v", line)
return
}
ans.file_extensions = utils.NewSet[string](len(r.Filetypes))
for _, ft := range r.Filetypes {
ans.file_extensions.Add("." + ft)
}
return
})
func calibre_cleanup() {
if !calibre_needs_cleanup.Load() {
return
}
calibre_needs_cleanup.Store(false)
calibre, _ := calibre_server()
if calibre.stdin != nil {
calibre.stdin.Close()
}
if calibre.stdout != nil {
calibre.stdout.Close()
}
if calibre.proc != nil {
calibre.proc.Wait()
}
}
func IsSupportedByCalibre(path string) bool {
ext := strings.ToLower(filepath.Ext(filepath.Base(path)))
if len(ext) > 1 {
if calibre_server_load_finished.Load() {
if calibre, err := calibre_server(); err == nil {
return calibre.file_extensions.Has(ext)
}
} else {
// we dont want to delay the render loop waiting for data from
// calibre-server as it causes flicker because the atomic update
// timeout expires, so use a default set of extensions.
go func() { _, _ = calibre_server() }()
return slices.Contains([]string{"cb7", "azw3", "kepub", "zip", "htmlz", "rar", "lrf", "cbr", "tpz", "azw1", "mobi", "lit", "pdf", "updb", "pml", "pobi", "fbz", "azw", "fb2", "cbc", "rtf", "snb", "opf", "txt", "epub", "oebzip", "txtz", "imp", "docx", "odt", "pdb", "rb", "prc", "html", "chm", "pmlz", "cbz", "lrx", "azw4"}, ext[1:])
}
}
return false
}
const CALIBRE_METADATA_KEY = "calibre-metadata.json"
type calibre_renderer int
func (c calibre_renderer) Unmarshall(m map[string]string) (any, error) {
data, err := os.ReadFile(m[CALIBRE_METADATA_KEY])
if err != nil {
return nil, err
}
var ans CalibreResponse
if err = json.Unmarshal(data, &ans); err != nil {
return nil, err
}
return &ans, nil
}
func (c calibre_renderer) Render(path string) (m map[string][]byte, mi metadata, img *images.ImageData, err error) {
cpath, err := os.CreateTemp("", "")
if err != nil {
return
}
defer func() {
cpath.Close()
os.Remove(cpath.Name())
}()
calibre, err := calibre_server()
if err != nil {
return
}
payload, err := json.Marshal(map[string]string{"path": path, "cover": cpath.Name()})
if err != nil {
return
}
calibre.stdin.Write(append(payload, '\n'))
line, err := ReadLineWithTimeout(calibre.stdout, 30*time.Second)
if err != nil {
return
}
lb := []byte(line)
var reply CalibreResponse
if err = json.Unmarshal(lb, &reply); err != nil {
return
}
if reply.Cover == cpath.Name() {
var ip ImagePreviewRenderer
if m, mi, img, err = ip.Render(cpath.Name()); err != nil {
return
}
} else {
m = make(map[string][]byte)
}
mi.custom = &reply
m[CALIBRE_METADATA_KEY] = lb
return
}
func (c calibre_renderer) ShowMetadata(h *Handler, s ShowData) (offset int) {
w := func(text string, center bool) {
if s.height > offset {
offset += h.render_wrapped_text_in_region(text, s.x, s.y+offset, s.width, s.height-offset, center)
}
}
ext := filepath.Ext(s.abspath)
text := fmt.Sprintf("%s: %s", ext, humanize.Bytes(uint64(s.metadata.Size())))
icon := icons.IconForPath(s.abspath)
w(icon+" "+text, true)
r := s.custom_metadata.custom.(*CalibreResponse)
w("Title: "+r.Metadata.Title, false)
w("Authors: "+strings.Join(r.Metadata.Authors, " & "), false)
if r.Metadata.Series != "" {
w(fmt.Sprintf("Series: Book %g of %s", r.Metadata.Series_index, r.Metadata.Series), false)
}
if len(r.Metadata.Tags) > 0 {
w("Tags: "+strings.Join(r.Metadata.Authors, ", "), false)
}
return
}
func (c calibre_renderer) String() string {
return "Calibre"
}
func NewCalibrePreview(
abspath string, metadata fs.FileInfo, opts Settings, WakeupMainThread func() bool,
) Preview {
c := calibre_renderer(0)
if ans, err := NewImagePreview(abspath, metadata, opts, WakeupMainThread, c); err == nil {
return ans
} else {
return NewErrorPreview(err)
}
}