From cdc6b5da52ef40f0ddea27ffc741c01211a5dcd7 Mon Sep 17 00:00:00 2001
From: Jean-Louis Huynen <huynenjl@gmail.com>
Date: Wed, 17 Feb 2021 15:05:17 +0100
Subject: [PATCH] add: [filerwatcher] wip

---
 inputreader/filewatcherreader.go | 92 ++++++++++++++++++++++----------
 1 file changed, 63 insertions(+), 29 deletions(-)

diff --git a/inputreader/filewatcherreader.go b/inputreader/filewatcherreader.go
index 2d98b26..4fd0aa4 100644
--- a/inputreader/filewatcherreader.go
+++ b/inputreader/filewatcherreader.go
@@ -5,7 +5,6 @@ import (
 	"encoding/base64"
 	"github.com/rjeczalik/notify"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 )
@@ -20,9 +19,13 @@ type FileWatcherReader struct {
 	// TearDown channel
 	exit chan string
 	// Current buffer
-	buf []byte
-	// json
 	json bool
+	// Current file
+	curfile *os.File
+	// Current state Watching / Reading
+	watching bool
+	// Insert Separator
+	insertsep bool
 }
 
 // NewFileWatcherReader creates a new FileWatcherReader
@@ -30,8 +33,10 @@ type FileWatcherReader struct {
 func NewFileWatcherReader(f *os.File, j bool) (*FileWatcherReader, error) {
 	r := &FileWatcherReader{
 		folderfd: f,
-		eic: make(chan notify.EventInfo, 1),
-		json: j,
+		eic:      make(chan notify.EventInfo, 4096),
+		json:     j,
+		watching: true,
+		insertsep: false,
 	}
 	// go routine holding the watcher
 	go func() {
@@ -47,43 +52,72 @@ func NewFileWatcherReader(f *os.File, j bool) (*FileWatcherReader, error) {
 // Read  waits for InCloseWrite file event uses a bytes reader to copy
 // the resulting file encoded in b64 in p
 func (fw *FileWatcherReader) Read(p []byte) (n int, err error) {
-	for{
-		select{
+
+	// Watching for new files to read
+	if fw.watching {
+	watchloop:
+		for {
+			select {
 			case ei := <-fw.eic:
-				log.Println("Got event:", ei)
+				//log.Println("Got event:", ei)
 				// New File, let's read its content
 				var err error
-				fw.buf, err = ioutil.ReadFile(ei.Path())
+				fw.curfile, err = os.Open(ei.Path())
 				if err != nil {
 					log.Fatal(err)
 				}
-				// if not json it could be anything so we encode it in b64
-				if !fw.json{
-					// base64 stream encoder
-					b64buf := new(bytes.Buffer)
-					b64encoder := base64.NewEncoder(base64.StdEncoding, b64buf)
-					// Encode in Base64 to b64buf
-					b64encoder.Write(fw.buf)
-					// Close the encoder to flush partially written blocks
-					b64encoder.Close()
-					b64buf.WriteString("\n")
-					//rreader := bytes.NewReader(fw.buf)
-					n, err = b64buf.Read(p)
-				}else{
-					fw.buf = append(fw.buf, "\n"...)
-					rreader := bytes.NewReader(fw.buf)
-					n, err = rreader.Read(p)
-					return n, err
-				}
-				return n, err
+				fw.watching = false
+				break watchloop
 			case <-fw.exit:
 				// Exiting
 				return 0, io.EOF
+			}
 		}
 	}
+
+	// Inserting separator
+	if fw.insertsep{
+		var buf []byte
+		buf = append(buf, "\n"...)
+		rreader := bytes.NewReader(buf)
+		n, err = rreader.Read(p)
+		fw.watching = true
+		fw.insertsep = false
+		log.Println("Inserting file seperator ")
+		fw.curfile.Close()
+		return n, err
+	}
+
+	// Reading
+	// if not json it could be anything so we encode it in b64
+	if !fw.json {
+		// base64 stream encoder
+		b64buffer := new(bytes.Buffer)
+		b64encoder := base64.NewEncoder(base64.StdEncoding, b64buffer)
+		// Read the file using p's length to get he correct size automatically
+		buf := make([]byte, len(p))
+		n, err = fw.curfile.Read(buf)
+		// buf is the input
+		b64encoder.Write(buf)
+		// Close the encoder to flush partially written blocks
+		b64encoder.Close()
+		if err == io.EOF {
+			fw.insertsep = true
+		}
+		// Copy from b64buffer to p
+		n, err = b64buffer.Read(p)
+		// I keep a len(p) buffer size as python knows how to handle the padding
+	} else {
+		n, err = fw.curfile.Read(p)
+		if err == io.EOF {
+			fw.insertsep = true
+		}
+	}
+	//log.Println("nread: ", n)
+	return n, err
 }
 
 // Teardown is called on error to stop the Reading loop if needed
 func (rl *FileWatcherReader) Teardown() {
 	rl.exit <- "exit"
-}
\ No newline at end of file
+}