Replace --header-file with --header (#346)

and allow using --header and --header-lines at the same time.

Close #346.

src/core.go

@@ -238,7 +238,7 @@ func Run(opts *Options) {
 					}
 
 				case EvtHeader:
-					terminal.UpdateHeader(value.([]string), opts.HeaderLines)
+					terminal.UpdateHeader(value.([]string))
 
 				case EvtSearchFin:
 					switch val := value.(type) {

src/options.go

@@ -1,7 +1,6 @@
 package fzf
 
 import (
-	"io/ioutil"
 	"os"
 	"regexp"
 	"strconv"
@@ -45,7 +44,7 @@ const usage = `usage: fzf [options]
     --bind=KEYBINDS       Custom key bindings. Refer to the man page.
     --history=FILE        History file
     --history-size=N      Maximum number of history entries (default: 1000)
-    --header-file=FILE    The file whose content to be printed as header
+    --header=STR          String to print as header
     --header-lines=N      The first N lines of the input are treated as header
 
   Scripting
@@ -604,12 +603,8 @@ func checkToggleSort(keymap map[int]actionType, str string) map[int]actionType {
 	return keymap
 }
 
-func readHeaderFile(filename string) []string {
-	content, err := ioutil.ReadFile(filename)
-	if err != nil {
-		errorExit("failed to read header file: " + filename)
-	}
-	return strings.Split(strings.TrimSuffix(string(content), "\n"), "\n")
+func strLines(str string) []string {
+	return strings.Split(strings.TrimSuffix(str, "\n"), "\n")
 }
 
 func parseMargin(margin string) [4]string {
@@ -793,16 +788,13 @@ func parseOptions(opts *Options, allArgs []string) {
 			setHistory(nextString(allArgs, &i, "history file path required"))
 		case "--history-size":
 			setHistoryMax(nextInt(allArgs, &i, "history max size required"))
-		case "--no-header-file":
+		case "--no-header":
 			opts.Header = []string{}
 		case "--no-header-lines":
 			opts.HeaderLines = 0
-		case "--header-file":
-			opts.Header = readHeaderFile(
-				nextString(allArgs, &i, "header file name required"))
-			opts.HeaderLines = 0
+		case "--header":
+			opts.Header = strLines(nextString(allArgs, &i, "header string required"))
 		case "--header-lines":
-			opts.Header = []string{}
 			opts.HeaderLines = atoi(
 				nextString(allArgs, &i, "number of header lines required"))
 		case "--no-margin":
@@ -843,11 +835,9 @@ func parseOptions(opts *Options, allArgs []string) {
 				setHistory(value)
 			} else if match, value := optString(arg, "--history-size="); match {
 				setHistoryMax(atoi(value))
-			} else if match, value := optString(arg, "--header-file="); match {
-				opts.Header = readHeaderFile(value)
-				opts.HeaderLines = 0
+			} else if match, value := optString(arg, "--header="); match {
+				opts.Header = strLines(value)
 			} else if match, value := optString(arg, "--header-lines="); match {
-				opts.Header = []string{}
 				opts.HeaderLines = atoi(value)
 			} else if match, value := optString(arg, "--margin="); match {
 				opts.Margin = parseMargin(value)

src/terminal.go

@@ -42,6 +42,7 @@ type Terminal struct {
 	history    *History
 	cycle      bool
 	header     []string
+	header0    []string
 	ansi       bool
 	margin     [4]string
 	marginInt  [4]int
@@ -185,6 +186,12 @@ func defaultKeymap() map[int]actionType {
 // NewTerminal returns new Terminal object
 func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 	input := []rune(opts.Query)
+	var header []string
+	if opts.Reverse {
+		header = opts.Header
+	} else {
+		header = reverseStringArray(opts.Header)
+	}
 	return &Terminal{
 		inlineInfo: opts.InlineInfo,
 		prompt:     opts.Prompt,
@@ -207,7 +214,8 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 		margin:     opts.Margin,
 		marginInt:  [4]int{0, 0, 0, 0},
 		cycle:      opts.Cycle,
-		header:     opts.Header,
+		header:     header,
+		header0:    header,
 		ansi:       opts.Ansi,
 		reading:    true,
 		merger:     EmptyMerger,
@@ -241,18 +249,19 @@ func (t *Terminal) UpdateCount(cnt int, final bool) {
 	}
 }
 
-// UpdateHeader updates the header
-func (t *Terminal) UpdateHeader(header []string, lines int) {
-	t.mutex.Lock()
-	t.header = make([]string, lines)
-	copy(t.header, header)
-	if !t.reverse {
-		reversed := make([]string, lines)
-		for idx, str := range t.header {
-			reversed[lines-idx-1] = str
-		}
-		t.header = reversed
+func reverseStringArray(input []string) []string {
+	size := len(input)
+	reversed := make([]string, size)
+	for idx, str := range input {
+		reversed[size-idx-1] = str
 	}
+	return reversed
+}
+
+// UpdateHeader updates the header
+func (t *Terminal) UpdateHeader(header []string) {
+	t.mutex.Lock()
+	t.header = append(append([]string{}, t.header0...), header...)
 	t.mutex.Unlock()
 	t.reqBox.Set(reqHeader, nil)
 }
@@ -436,9 +445,6 @@ func (t *Terminal) printHeader() {
 	max := t.maxHeight()
 	var state *ansiState
 	for idx, lineStr := range t.header {
-		if !t.reverse {
-			idx = len(t.header) - idx - 1
-		}
 		line := idx + 2
 		if t.inlineInfo {
 			line--