142 lines
3.0 KiB
Go
142 lines
3.0 KiB
Go
package commands
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"os"
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"path"
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"sync"
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"git.sr.ht/~rjarry/aerc/logging"
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"github.com/kyoh86/xdg"
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)
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type cmdHistory struct {
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// rolling buffer of prior commands
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//
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// most recent command is at the end of the list,
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// least recent is index 0
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cmdList []string
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// current placement in list
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current int
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// initialize history storage
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initHistfile sync.Once
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histfile io.ReadWriter
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}
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// number of commands to keep in history
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const cmdLimit = 1000
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// CmdHistory is the history of executed commands
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var CmdHistory = cmdHistory{}
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func (h *cmdHistory) Add(cmd string) {
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h.initHistfile.Do(h.initialize)
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// if we're at cap, cut off the first element
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if len(h.cmdList) >= cmdLimit {
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h.cmdList = h.cmdList[1:]
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}
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if len(h.cmdList) == 0 || h.cmdList[len(h.cmdList)-1] != cmd {
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h.cmdList = append(h.cmdList, cmd)
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h.writeHistory()
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}
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// whenever we add a new command, reset the current
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// pointer to the "beginning" of the list
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h.Reset()
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}
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// Prev returns the previous command in history.
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// Since the list is reverse-order, this will return elements
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// increasingly towards index 0.
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func (h *cmdHistory) Prev() string {
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h.initHistfile.Do(h.initialize)
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if h.current <= 0 || len(h.cmdList) == 0 {
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h.current = -1
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return "(Already at beginning)"
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}
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h.current--
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return h.cmdList[h.current]
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}
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// Next returns the next command in history.
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// Since the list is reverse-order, this will return elements
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// increasingly towards index len(cmdList).
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func (h *cmdHistory) Next() string {
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h.initHistfile.Do(h.initialize)
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if h.current >= len(h.cmdList)-1 || len(h.cmdList) == 0 {
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h.current = len(h.cmdList)
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return "(Already at end)"
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}
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h.current++
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return h.cmdList[h.current]
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}
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// Reset the current pointer to the beginning of history.
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func (h *cmdHistory) Reset() {
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h.current = len(h.cmdList)
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}
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func (h *cmdHistory) initialize() {
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var err error
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openFlags := os.O_RDWR | os.O_EXCL
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histPath := path.Join(xdg.CacheHome(), "aerc", "history")
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if _, err := os.Stat(histPath); os.IsNotExist(err) {
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_ = os.MkdirAll(path.Join(xdg.CacheHome(), "aerc"), 0o700) // caught by OpenFile
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openFlags |= os.O_CREATE
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}
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// O_EXCL to make sure that only one aerc writes to the file
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h.histfile, err = os.OpenFile(
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histPath,
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openFlags,
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0o600,
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)
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if err != nil {
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logging.Errorf("failed to open history file: %v", err)
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// basically mirror the old behavior
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h.histfile = bytes.NewBuffer([]byte{})
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return
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}
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s := bufio.NewScanner(h.histfile)
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for s.Scan() {
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h.cmdList = append(h.cmdList, s.Text())
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}
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h.Reset()
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}
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func (h *cmdHistory) writeHistory() {
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if fh, ok := h.histfile.(*os.File); ok {
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err := fh.Truncate(0)
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if err != nil {
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// if we can't delete it, don't break it.
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return
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}
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_, err = fh.Seek(0, io.SeekStart)
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if err != nil {
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// if we can't delete it, don't break it.
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return
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}
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for _, entry := range h.cmdList {
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fmt.Fprintln(fh, entry)
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}
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fh.Sync() //nolint:errcheck // if your computer can't sync you're in bigger trouble
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}
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}
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