From d6e6ddf99685dbd365c0154796ffd0cb2df584f6 Mon Sep 17 00:00:00 2001
From: "xubin.gao" <xubin.gao@hiwifi.tw>
Date: Sun, 29 Dec 2019 19:24:56 +0800
Subject: [PATCH] Add gfile.ReadLines and gfile.ReadByteLines read file content
 line by line

---
 os/gfile/gfile_contents.go          | 35 +++++++++++++++++
 os/gfile/gfile_z_readline_test.go   | 59 +++++++++++++++++++++++++++++
 os/gfile/testdata/readline/file.log |  5 +++
 3 files changed, 99 insertions(+)
 create mode 100644 os/gfile/gfile_z_readline_test.go
 create mode 100644 os/gfile/testdata/readline/file.log

diff --git a/os/gfile/gfile_contents.go b/os/gfile/gfile_contents.go
index 4823e0f8b..bf3c77594 100644
--- a/os/gfile/gfile_contents.go
+++ b/os/gfile/gfile_contents.go
@@ -7,9 +7,12 @@
 package gfile
 
 import (
+	"bufio"
 	"io"
 	"io/ioutil"
 	"os"
+
+	"github.com/gogf/gf/util/gconv"
 )
 
 var (
@@ -160,3 +163,35 @@ func GetBytesByTwoOffsetsByPath(path string, start int64, end int64) []byte {
 	}
 	return nil
 }
+
+// ReadLines reads file content line by line, which is passed to the callback function <callback> as string.
+// It matches each line of text, separated by chars '\r' or '\n', stripped any trailing end-of-line marker.
+//
+// Note that the parameter passed to callback function might be an empty value, and the last non-empty line
+// will be passed to callback function <callback> even if it has no newline marker.
+func ReadLines(file string, callback func(text string)) error {
+	cb := func(bytes []byte) {
+		callback(gconv.UnsafeBytesToStr(bytes))
+	}
+	return ReadByteLines(file, cb)
+}
+
+// ReadByteLines reads file content line by line, which is passed to the callback function <callback> as []byte.
+// It matches each line of text, separated by chars '\r' or '\n', stripped any trailing end-of-line marker.
+//
+// Note that the parameter passed to callback function might be an empty value, and the last non-empty line
+// will be passed to callback function <callback> even if it has no newline marker.
+func ReadByteLines(file string, callback func(bytes []byte)) error {
+	f, err := os.Open(file)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+
+	for scanner.Scan() {
+		callback(scanner.Bytes())
+	}
+	return nil
+}
diff --git a/os/gfile/gfile_z_readline_test.go b/os/gfile/gfile_z_readline_test.go
new file mode 100644
index 000000000..8fe537cf1
--- /dev/null
+++ b/os/gfile/gfile_z_readline_test.go
@@ -0,0 +1,59 @@
+// Copyright 2017-2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package gfile_test
+
+import (
+	"github.com/gogf/gf/debug/gdebug"
+	"testing"
+
+	"github.com/gogf/gf/os/gfile"
+	"github.com/gogf/gf/test/gtest"
+)
+
+func Test_NotFound(t *testing.T) {
+	gtest.Case(t, func() {
+		teatFile := gfile.Dir(gdebug.CallerFilePath()) + gfile.Separator + "testdata/readline/error.log"
+		callback := func(line string) {
+		}
+		err := gfile.ReadLines(teatFile, callback)
+		gtest.AssertNE(err, nil)
+	})
+}
+
+func Test_ReadLines(t *testing.T) {
+	gtest.Case(t, func() {
+		expectList := []string{"a", "b", "c", "d", "e"}
+
+		getList := make([]string, 0)
+		callback := func(line string) {
+			getList = append(getList, line)
+		}
+
+		teatFile := gfile.Dir(gdebug.CallerFilePath()) + gfile.Separator + "testdata/readline/file.log"
+		err := gfile.ReadLines(teatFile, callback)
+
+		gtest.AssertEQ(getList, expectList)
+		gtest.AssertEQ(err, nil)
+	})
+}
+
+func Test_ReadByteLines(t *testing.T) {
+	gtest.Case(t, func() {
+		expectList := [][]byte{[]byte("a"), []byte("b"), []byte("c"), []byte("d"), []byte("e")}
+
+		getList := make([][]byte, 0)
+		callback := func(line []byte) {
+			getList = append(getList, line)
+		}
+
+		teatFile := gfile.Dir(gdebug.CallerFilePath()) + gfile.Separator + "testdata/readline/file.log"
+		err := gfile.ReadByteLines(teatFile, callback)
+
+		gtest.AssertEQ(getList, expectList)
+		gtest.AssertEQ(err, nil)
+	})
+}
diff --git a/os/gfile/testdata/readline/file.log b/os/gfile/testdata/readline/file.log
new file mode 100644
index 000000000..940532533
--- /dev/null
+++ b/os/gfile/testdata/readline/file.log
@@ -0,0 +1,5 @@
+a
+b
+c
+d
+e