From a9dff6da7391297b64bb5be473b76c3c590f34a1 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Wed, 29 Apr 2020 02:45:54 +0300
Subject: Add support for encrypted files

---
 matrix/matrix.go | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

(limited to 'matrix')

diff --git a/matrix/matrix.go b/matrix/matrix.go
index 8d7595e..27ed053 100644
--- a/matrix/matrix.go
+++ b/matrix/matrix.go
@@ -17,7 +17,6 @@
 package matrix
 
 import (
-	"bytes"
 	"context"
 	"crypto/tls"
 	"encoding/gob"
@@ -38,6 +37,7 @@ import (
 
 	"maunium.net/go/mautrix"
 	"maunium.net/go/mautrix/crypto"
+	"maunium.net/go/mautrix/crypto/attachment"
 	"maunium.net/go/mautrix/event"
 	"maunium.net/go/mautrix/format"
 	"maunium.net/go/mautrix/id"
@@ -1061,7 +1061,7 @@ func cp(src, dst string) error {
 	return out.Close()
 }
 
-func (c *Container) DownloadToDisk(uri id.ContentURI, target string) (fullPath string, err error) {
+func (c *Container) DownloadToDisk(uri id.ContentURI, file *attachment.EncryptedFile, target string) (fullPath string, err error) {
 	cachePath := c.GetCachePath(uri)
 	if target == "" {
 		fullPath = cachePath
@@ -1072,21 +1072,27 @@ func (c *Container) DownloadToDisk(uri id.ContentURI, target string) (fullPath s
 	}
 
 	if _, statErr := os.Stat(cachePath); os.IsNotExist(statErr) {
-		var file *os.File
-		file, err = os.OpenFile(cachePath, os.O_CREATE|os.O_WRONLY, 0600)
+		var body io.ReadCloser
+		body, err = c.client.Download(uri)
 		if err != nil {
 			return
 		}
-		defer file.Close()
 
-		var body io.ReadCloser
-		body, err = c.client.Download(uri)
+		var data []byte
+		data, err = ioutil.ReadAll(body)
+		_ = body.Close()
 		if err != nil {
 			return
 		}
-		defer body.Close()
 
-		_, err = io.Copy(file, body)
+		if file != nil {
+			data, err = file.Decrypt(data)
+			if err != nil {
+				return
+			}
+		}
+
+		err = ioutil.WriteFile(cachePath, data, 0600)
 		if err != nil {
 			return
 		}
@@ -1106,7 +1112,7 @@ func (c *Container) DownloadToDisk(uri id.ContentURI, target string) (fullPath s
 // Download fetches the given Matrix content (mxc) URL and returns the data, homeserver, file ID and potential errors.
 //
 // The file will be either read from the media cache (if found) or downloaded from the server.
-func (c *Container) Download(uri id.ContentURI) (data []byte, err error) {
+func (c *Container) Download(uri id.ContentURI, file *attachment.EncryptedFile) (data []byte, err error) {
 	cacheFile := c.GetCachePath(uri)
 	var info os.FileInfo
 	if info, err = os.Stat(cacheFile); err == nil && !info.IsDir() {
@@ -1116,7 +1122,7 @@ func (c *Container) Download(uri id.ContentURI) (data []byte, err error) {
 		}
 	}
 
-	data, err = c.download(uri, cacheFile)
+	data, err = c.download(uri, file, cacheFile)
 	return
 }
 
@@ -1124,21 +1130,25 @@ func (c *Container) GetDownloadURL(uri id.ContentURI) string {
 	return c.client.GetDownloadURL(uri)
 }
 
-func (c *Container) download(uri id.ContentURI, cacheFile string) (data []byte, err error) {
+func (c *Container) download(uri id.ContentURI, file *attachment.EncryptedFile, cacheFile string) (data []byte, err error) {
 	var body io.ReadCloser
 	body, err = c.client.Download(uri)
 	if err != nil {
 		return
 	}
-	defer body.Close()
 
-	var buf bytes.Buffer
-	_, err = io.Copy(&buf, body)
+	data, err = ioutil.ReadAll(body)
+	_ = body.Close()
 	if err != nil {
 		return
 	}
 
-	data = buf.Bytes()
+	if file != nil {
+		data, err = file.Decrypt(data)
+		if err != nil {
+			return
+		}
+	}
 
 	err = ioutil.WriteFile(cacheFile, data, 0600)
 	return
-- 
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