From a809085bff595080269599dbe788dd7fdf616ab4 Mon Sep 17 00:00:00 2001 From: Laurent Demailly Date: Fri, 18 Apr 2025 18:46:24 +0000 Subject: [PATCH 1/2] term: support pluggable history Expose a new History interface that allows replacement of the default ring buffer to customize what gets added or not; as well as to allow saving/restoring history on either the default ringbuffer or a custom replacement. Fixes golang/go#68780 Change-Id: I7e61dc6bb438749c8502223705518ef8ff9025b4 GitHub-Last-Rev: 621281355fd577da77f135c4e15552eba3ead584 GitHub-Pull-Request: golang/term#20 Reviewed-on: https://go-review.googlesource.com/c/term/+/659835 Reviewed-by: Michael Pratt Auto-Submit: Jorropo LUCI-TryBot-Result: Go LUCI Reviewed-by: Jorropo Reviewed-by: Austin Clements --- terminal.go | 68 +++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 58 insertions(+), 10 deletions(-) diff --git a/terminal.go b/terminal.go index 14f8947..13e9a64 100644 --- a/terminal.go +++ b/terminal.go @@ -6,6 +6,7 @@ package term import ( "bytes" + "fmt" "io" "runtime" "strconv" @@ -36,6 +37,26 @@ var vt100EscapeCodes = EscapeCodes{ Reset: []byte{keyEscape, '[', '0', 'm'}, } +// A History provides a (possibly bounded) queue of input lines read by [Terminal.ReadLine]. +type History interface { + // Add will be called by [Terminal.ReadLine] to add + // a new, most recent entry to the history. + // It is allowed to drop any entry, including + // the entry being added (e.g., if it's deemed an invalid entry), + // the least-recent entry (e.g., to keep the history bounded), + // or any other entry. + Add(entry string) + + // Len returns the number of entries in the history. + Len() int + + // At returns an entry from the history. + // Index 0 is the most-recently added entry and + // index Len()-1 is the least-recently added entry. + // If index is < 0 or >= Len(), it panics. + At(idx int) string +} + // Terminal contains the state for running a VT100 terminal that is capable of // reading lines of input. type Terminal struct { @@ -86,9 +107,14 @@ type Terminal struct { remainder []byte inBuf [256]byte - // history contains previously entered commands so that they can be - // accessed with the up and down keys. - history stRingBuffer + // History records and retrieves lines of input read by [ReadLine] which + // a user can retrieve and navigate using the up and down arrow keys. + // + // It is not safe to call ReadLine concurrently with any methods on History. + // + // [NewTerminal] sets this to a default implementation that records the + // last 100 lines of input. + History History // historyIndex stores the currently accessed history entry, where zero // means the immediately previous entry. historyIndex int @@ -111,6 +137,7 @@ func NewTerminal(c io.ReadWriter, prompt string) *Terminal { termHeight: 24, echo: true, historyIndex: -1, + History: &stRingBuffer{}, } } @@ -450,6 +477,23 @@ func visualLength(runes []rune) int { return length } +// histroryAt unlocks the terminal and relocks it while calling History.At. +func (t *Terminal) historyAt(idx int) (string, bool) { + t.lock.Unlock() // Unlock to avoid deadlock if History methods use the output writer. + defer t.lock.Lock() // panic in At (or Len) protection. + if idx < 0 || idx >= t.History.Len() { + return "", false + } + return t.History.At(idx), true +} + +// historyAdd unlocks the terminal and relocks it while calling History.Add. +func (t *Terminal) historyAdd(entry string) { + t.lock.Unlock() // Unlock to avoid deadlock if History methods use the output writer. + defer t.lock.Lock() // panic in Add protection. + t.History.Add(entry) +} + // handleKey processes the given key and, optionally, returns a line of text // that the user has entered. func (t *Terminal) handleKey(key rune) (line string, ok bool) { @@ -497,7 +541,7 @@ func (t *Terminal) handleKey(key rune) (line string, ok bool) { t.pos = len(t.line) t.moveCursorToPos(t.pos) case keyUp: - entry, ok := t.history.NthPreviousEntry(t.historyIndex + 1) + entry, ok := t.historyAt(t.historyIndex + 1) if !ok { return "", false } @@ -516,7 +560,7 @@ func (t *Terminal) handleKey(key rune) (line string, ok bool) { t.setLine(runes, len(runes)) t.historyIndex-- default: - entry, ok := t.history.NthPreviousEntry(t.historyIndex - 1) + entry, ok := t.historyAt(t.historyIndex - 1) if ok { t.historyIndex-- runes := []rune(entry) @@ -781,7 +825,7 @@ func (t *Terminal) readLine() (line string, err error) { if lineOk { if t.echo { t.historyIndex = -1 - t.history.Add(line) + t.historyAdd(line) } if lineIsPasted { err = ErrPasteIndicator @@ -938,19 +982,23 @@ func (s *stRingBuffer) Add(a string) { } } -// NthPreviousEntry returns the value passed to the nth previous call to Add. +func (s *stRingBuffer) Len() int { + return s.size +} + +// At returns the value passed to the nth previous call to Add. // If n is zero then the immediately prior value is returned, if one, then the // next most recent, and so on. If such an element doesn't exist then ok is // false. -func (s *stRingBuffer) NthPreviousEntry(n int) (value string, ok bool) { +func (s *stRingBuffer) At(n int) string { if n < 0 || n >= s.size { - return "", false + panic(fmt.Sprintf("term: history index [%d] out of range [0,%d)", n, s.size)) } index := s.head - n if index < 0 { index += s.max } - return s.entries[index], true + return s.entries[index] } // readPasswordLine reads from reader until it finds \n or io.EOF. From 2ec7864a3e7b8faa620696c32a0738119e2477e1 Mon Sep 17 00:00:00 2001 From: Gopher Robot Date: Mon, 5 May 2025 06:02:04 -0700 Subject: [PATCH 2/2] go.mod: update golang.org/x dependencies Update golang.org/x dependencies to their latest tagged versions. Change-Id: I044141b4808276d77216779c66fa057da6143ad3 Reviewed-on: https://go-review.googlesource.com/c/term/+/669916 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Auto-Submit: Gopher Robot Reviewed-by: Dmitri Shuralyov --- go.mod | 2 +- go.sum | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/go.mod b/go.mod index eb31235..595089d 100644 --- a/go.mod +++ b/go.mod @@ -2,4 +2,4 @@ module golang.org/x/term go 1.23.0 -require golang.org/x/sys v0.32.0 +require golang.org/x/sys v0.33.0 diff --git a/go.sum b/go.sum index 5d30cb5..9e6ab4c 100644 --- a/go.sum +++ b/go.sum @@ -1,2 +1,2 @@ -golang.org/x/sys v0.32.0 h1:s77OFDvIQeibCmezSnk/q6iAfkdiQaJi4VzroCFrN20= -golang.org/x/sys v0.32.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k= +golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw= +golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=