Extend placeholder expression for multiple selections

Close #788

4 files changed, 141 insertions, 42 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4358226..4dd6e9c4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 CHANGELOG
 =========
 
+0.16.3
+------
+- Fixed a bug where fzf incorrectly display the lines when straddling tab
+  characters are trimmed
+- Placeholder expression used in `--preview` and `execute` action can
+  optionally take `+` flag to be used with multiple selections
+    - e.g. `git log --oneline | fzf --multi --preview 'git show {+1}'`
+
 0.16.2
 ------
 - Dropped ncurses dependency
diff --git a/man/man1/fzf.1 b/man/man1/fzf.1
index 9a374d5b..e4321baa 100644
--- a/man/man1/fzf.1
+++ b/man/man1/fzf.1
@@ -262,13 +262,21 @@ Execute the given command for the current line and display the result on the
 preview window. \fB{}\fR in the command is the placeholder that is replaced to
 the single-quoted string of the current line. To transform the replacement
 string, specify field index expressions between the braces (See \fBFIELD INDEX
-EXPRESSION\fR for the details). Also, \fB{q}\fR is replaced to the current
-query string.
+EXPRESSION\fR for the details).
 
 .RS
 e.g. \fBfzf --preview="head -$LINES {}"\fR
      \fBls -l | fzf --preview="echo user={3} when={-4..-2}; cat {-1}" --header-lines=1\fR
 
+A placeholder expression starting with \fB+\fR flag will be replaced to the
+space-separated list of the selected lines (or the current line if no selection
+was made) individually quoted.
+
+e.g. \fBfzf --multi --preview="head -10 {+}"\fR
+     \fBgit log --oneline | fzf --multi --preview 'git show {+1}'\fR
+
+Also, \fB{q}\fR is replaced to the current query string.
+
 Note that you can escape a placeholder pattern by prepending a backslash.
 .RE
 .TP
@@ -461,7 +469,7 @@ e.g. \fBfzf --bind=ctrl-j:accept,ctrl-k:kill-line\fR
     \fBdown\fR                  \fIctrl-j  ctrl-n  down\fR
     \fBend-of-line\fR           \fIctrl-e  end\fR
     \fBexecute(...)\fR          (see below for the details)
-    \fBexecute-multi(...)\fR    (see below for the details)
+    \fRexecute-multi(...)\fR    (deprecated in favor of \fB{+}\fR expression)
     \fBforward-char\fR          \fIctrl-f  right\fR
     \fBforward-word\fR          \fIalt-f   shift-right\fR
     \fBignore\fR
diff --git a/src/terminal.go b/src/terminal.go
index 081f7156..43d21d88 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -24,7 +24,7 @@ import (
 var placeholder *regexp.Regexp
 
 func init() {
-	placeholder = regexp.MustCompile("\\\\?(?:{[0-9,-.]*}|{q})")
+	placeholder = regexp.MustCompile("\\\\?(?:{\\+?[0-9,-.]*}|{q})")
 }
 
 type jumpMode int
@@ -436,9 +436,9 @@ func (t *Terminal) output() bool {
 	}
 	found := len(t.selected) > 0
 	if !found {
-		cnt := t.merger.Length()
-		if cnt > 0 && cnt > t.cy {
-			t.printer(t.current())
+		current := t.currentItem()
+		if current != nil {
+			t.printer(current.AsString(t.ansi))
 			found = true
 		}
 	} else {
@@ -1044,7 +1044,27 @@ func quoteEntry(entry string) string {
 	return "'" + strings.Replace(entry, "'", "'\\''", -1) + "'"
 }
 
-func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, query string, items []*Item) string {
+func hasPlusFlag(template string) bool {
+	for _, match := range placeholder.FindAllString(template, -1) {
+		if match[0] == '\\' {
+			continue
+		}
+		if match[1] == '+' {
+			return true
+		}
+	}
+	return false
+}
+
+func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, forcePlus bool, query string, allItems []*Item) string {
+	current := allItems[:1]
+	selected := allItems[1:]
+	if current[0] == nil {
+		current = []*Item{}
+	}
+	if selected[0] == nil {
+		selected = []*Item{}
+	}
 	return placeholder.ReplaceAllStringFunc(template, func(match string) string {
 		// Escaped pattern
 		if match[0] == '\\' {
@@ -1056,6 +1076,16 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, qu
 			return quoteEntry(query)
 		}
 
+		plusFlag := forcePlus
+		if match[1] == '+' {
+			match = "{" + match[2:]
+			plusFlag = true
+		}
+		items := current
+		if plusFlag {
+			items = selected
+		}
+
 		replacements := make([]string, len(items))
 
 		if match == "{}" {
@@ -1096,8 +1126,12 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, qu
 	})
 }
 
-func (t *Terminal) executeCommand(template string, items []*Item) {
-	command := replacePlaceholder(template, t.ansi, t.delimiter, string(t.input), items)
+func (t *Terminal) executeCommand(template string, forcePlus bool) {
+	valid, list := t.buildPlusList(template, forcePlus)
+	if !valid {
+		return
+	}
+	command := replacePlaceholder(template, t.ansi, t.delimiter, forcePlus, string(t.input), list)
 	cmd := util.ExecCommand(command)
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
@@ -1123,11 +1157,24 @@ func (t *Terminal) hasPreviewWindow() bool {
 }
 
 func (t *Terminal) currentItem() *Item {
-	return t.merger.Get(t.cy).item
+	cnt := t.merger.Length()
+	if cnt > 0 && cnt > t.cy {
+		return t.merger.Get(t.cy).item
+	}
+	return nil
 }
 
-func (t *Terminal) current() string {
-	return t.currentItem().AsString(t.ansi)
+func (t *Terminal) buildPlusList(template string, forcePlus bool) (bool, []*Item) {
+	current := t.currentItem()
+	if !forcePlus && !hasPlusFlag(template) || len(t.selected) == 0 {
+		return current != nil, []*Item{current, current}
+	}
+	sels := make([]*Item, len(t.selected)+1)
+	sels[0] = current
+	for i, sel := range t.sortSelected() {
+		sels[i+1] = sel.item
+	}
+	return true, sels
 }
 
 // Loop is called to start Terminal I/O
@@ -1184,19 +1231,20 @@ func (t *Terminal) Loop() {
 	if t.hasPreviewer() {
 		go func() {
 			for {
-				var request *Item
+				var request []*Item
 				t.previewBox.Wait(func(events *util.Events) {
 					for req, value := range *events {
 						switch req {
 						case reqPreviewEnqueue:
-							request = value.(*Item)
+							request = value.([]*Item)
 						}
 					}
 					events.Clear()
 				})
-				if request != nil {
+				// We don't display preview window if no match
+				if request[0] != nil {
 					command := replacePlaceholder(t.preview.command,
-						t.ansi, t.delimiter, string(t.input), []*Item{request})
+						t.ansi, t.delimiter, false, string(t.input), request)
 					cmd := util.ExecCommand(command)
 					out, _ := cmd.CombinedOutput()
 					t.reqBox.Set(reqPreviewDisplay, string(out))
@@ -1232,17 +1280,12 @@ func (t *Terminal) Loop() {
 						t.printInfo()
 					case reqList:
 						t.printList()
-						cnt := t.merger.Length()
-						var currentFocus *Item
-						if cnt > 0 && cnt > t.cy {
-							currentFocus = t.currentItem()
-						} else {
-							currentFocus = nil
-						}
+						currentFocus := t.currentItem()
 						if currentFocus != focused {
 							focused = currentFocus
 							if t.isPreviewEnabled() {
-								t.previewBox.Set(reqPreviewEnqueue, focused)
+								_, list := t.buildPlusList(t.preview.command, false)
+								t.previewBox.Set(reqPreviewEnqueue, list)
 							}
 						}
 					case reqJump:
@@ -1348,19 +1391,9 @@ func (t *Terminal) Loop() {
 			switch a.t {
 			case actIgnore:
 			case actExecute:
-				if t.cy >= 0 && t.cy < t.merger.Length() {
-					t.executeCommand(a.a, []*Item{t.currentItem()})
-				}
+				t.executeCommand(a.a, false)
 			case actExecuteMulti:
-				if len(t.selected) > 0 {
-					sels := make([]*Item, len(t.selected))
-					for i, sel := range t.sortSelected() {
-						sels[i] = sel.item
-					}
-					t.executeCommand(a.a, sels)
-				} else {
-					return doAction(action{t: actExecute, a: a.a}, mapkey)
-				}
+				t.executeCommand(a.a, true)
 			case actInvalid:
 				t.mutex.Unlock()
 				return false
@@ -1369,9 +1402,11 @@ func (t *Terminal) Loop() {
 					t.previewer.enabled = !t.previewer.enabled
 					t.tui.Clear()
 					t.resizeWindows()
-					cnt := t.merger.Length()
-					if t.previewer.enabled && cnt > 0 && cnt > t.cy {
-						t.previewBox.Set(reqPreviewEnqueue, t.currentItem())
+					if t.previewer.enabled {
+						valid, list := t.buildPlusList(t.preview.command, false)
+						if valid {
+							t.previewBox.Set(reqPreviewEnqueue, list)
+						}
 					}
 					req(reqList, reqInfo, reqHeader)
 				}
diff --git a/test/test_go.rb b/test/test_go.rb
index cdd96d10..f730f256 100644
--- a/test/test_go.rb
+++ b/test/test_go.rb
@@ -879,7 +879,7 @@ class TestGoFZF < TestBase
 
   def test_execute_multi
     output = '/tmp/fzf-test-execute-multi'
-    opts = %[--multi --bind \\"alt-a:execute-multi(echo {}/{} >> #{output}; sync)\\"]
+    opts = %[--multi --bind \\"alt-a:execute-multi(echo {}/{+} >> #{output}; sync)\\"]
     writelines tempname, %w[foo'bar foo"bar foo$bar foobar]
     tmux.send_keys "cat #{tempname} | #{fzf opts}", :Enter
     tmux.until { |lines| lines[-2].include? '4/4' }
@@ -902,6 +902,43 @@ class TestGoFZF < TestBase
     File.unlink output rescue nil
   end
 
+  def test_execute_plus_flag
+    output = tempname + ".tmp"
+    File.unlink output rescue nil
+    writelines tempname, ["foo bar", "123 456"]
+
+    tmux.send_keys "cat #{tempname} | #{FZF} --multi --bind 'x:execute(echo {+}/{}/{+2}/{2} >> #{output})'", :Enter
+
+    execute = lambda do
+      tmux.send_keys 'x', 'y'
+      tmux.until { |lines| lines[-2].include? '0/2' }
+      tmux.send_keys :BSpace
+      tmux.until { |lines| lines[-2].include? '2/2' }
+    end
+
+    tmux.until { |lines| lines[-2].include? '2/2' }
+    execute.call
+
+    tmux.send_keys :Up
+    tmux.send_keys :Tab
+    execute.call
+
+    tmux.send_keys :Tab
+    execute.call
+
+    tmux.send_keys :Enter
+    tmux.prepare
+    readonce
+
+    assert_equal [
+      %[foo bar/foo bar/bar/bar],
+      %[123 456/foo bar/456/bar],
+      %[123 456 foo bar/foo bar/456 bar/bar]
+    ], File.readlines(output).map(&:chomp)
+  rescue
+    File.unlink output rescue nil
+  end
+
   def test_execute_shell
     # Custom script to use as $SHELL
     output = tempname + '.out'
@@ -1198,7 +1235,7 @@ class TestGoFZF < TestBase
   end
 
   def test_preview
-    tmux.send_keys %[seq 1000 | sed s/^2$// | #{FZF} --preview 'sleep 0.2; echo {{}-{}}' --bind ?:toggle-preview], :Enter
+    tmux.send_keys %[seq 1000 | sed s/^2$// | #{FZF} -m --preview 'sleep 0.2; echo {{}-{+}}' --bind ?:toggle-preview], :Enter
     tmux.until { |lines| lines[1].include?(' {1-1}') }
     tmux.send_keys :Up
     tmux.until { |lines| lines[1].include?(' {-}') }
@@ -1212,6 +1249,17 @@ class TestGoFZF < TestBase
     tmux.until { |lines| lines[-2].start_with? '  28/1000' }
     tmux.send_keys 'foobar'
     tmux.until { |lines| !lines[1].include?('{') }
+    tmux.send_keys 'C-u'
+    tmux.until { |lines| lines.match_count == 1000 }
+    tmux.until { |lines| lines[1].include?(' {1-1}') }
+    tmux.send_keys :BTab
+    tmux.until { |lines| lines[1].include?(' {-1}') }
+    tmux.send_keys :BTab
+    tmux.until { |lines| lines[1].include?(' {3-1 }') }
+    tmux.send_keys :BTab
+    tmux.until { |lines| lines[1].include?(' {4-1  3}') }
+    tmux.send_keys :BTab
+    tmux.until { |lines| lines[1].include?(' {5-1  3 4}') }
   end
 
   def test_preview_hidden