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package commands
import (
"bufio"
"bytes"
"fmt"
"io"
"os"
"sync"
"git.sr.ht/~rjarry/aerc/lib/log"
"git.sr.ht/~rjarry/aerc/lib/xdg"
)
type cmdHistory struct {
// rolling buffer of prior commands
//
// most recent command is at the end of the list,
// least recent is index 0
cmdList []string
// current placement in list
current int
// initialize history storage
initHistfile sync.Once
histfile io.ReadWriter
}
// number of commands to keep in history
const cmdLimit = 1000
// CmdHistory is the history of executed commands
var CmdHistory = cmdHistory{}
func (h *cmdHistory) Add(cmd string) {
h.initHistfile.Do(h.initialize)
// if we're at cap, cut off the first element
if len(h.cmdList) >= cmdLimit {
h.cmdList = h.cmdList[1:]
}
if len(h.cmdList) == 0 || h.cmdList[len(h.cmdList)-1] != cmd {
h.cmdList = append(h.cmdList, cmd)
h.writeHistory()
}
// whenever we add a new command, reset the current
// pointer to the "beginning" of the list
h.Reset()
}
// Prev returns the previous command in history.
// Since the list is reverse-order, this will return elements
// increasingly towards index 0.
func (h *cmdHistory) Prev() string {
h.initHistfile.Do(h.initialize)
if h.current <= 0 || len(h.cmdList) == 0 {
h.current = -1
return "(Already at beginning)"
}
h.current--
return h.cmdList[h.current]
}
// Next returns the next command in history.
// Since the list is reverse-order, this will return elements
// increasingly towards index len(cmdList).
func (h *cmdHistory) Next() string {
h.initHistfile.Do(h.initialize)
if h.current >= len(h.cmdList)-1 || len(h.cmdList) == 0 {
h.current = len(h.cmdList)
return "(Already at end)"
}
h.current++
return h.cmdList[h.current]
}
// Reset the current pointer to the beginning of history.
func (h *cmdHistory) Reset() {
h.current = len(h.cmdList)
}
func (h *cmdHistory) initialize() {
var err error
openFlags := os.O_RDWR | os.O_EXCL
histPath := xdg.CachePath("aerc", "history")
if _, err := os.Stat(histPath); os.IsNotExist(err) {
_ = os.MkdirAll(xdg.CachePath("aerc"), 0o700) // caught by OpenFile
openFlags |= os.O_CREATE
}
// O_EXCL to make sure that only one aerc writes to the file
h.histfile, err = os.OpenFile(
histPath,
openFlags,
0o600,
)
if err != nil {
log.Errorf("failed to open history file: %v", err)
// basically mirror the old behavior
h.histfile = bytes.NewBuffer([]byte{})
return
}
s := bufio.NewScanner(h.histfile)
for s.Scan() {
h.cmdList = append(h.cmdList, s.Text())
}
h.Reset()
}
func (h *cmdHistory) writeHistory() {
if fh, ok := h.histfile.(*os.File); ok {
err := fh.Truncate(0)
if err != nil {
// if we can't delete it, don't break it.
return
}
_, err = fh.Seek(0, io.SeekStart)
if err != nil {
// if we can't delete it, don't break it.
return
}
for _, entry := range h.cmdList {
fmt.Fprintln(fh, entry)
}
fh.Sync() //nolint:errcheck // if your computer can't sync you're in bigger trouble
}
}
|
