[Spice-commits] vdagent/file_xfer.cpp

[Jonathon Jongsma]

 vdagent/file_xfer.cpp |   39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

New commits:
commit 241425b7da80626f0d3bc471202e753f0f1dd178
Author: Frediano Ziglio <fziglio at redhat.com>
Date:   Wed Apr 26 15:34:53 2017 -0500

    Support file transfer for existing files
    
    Previously, if the user attempted to transfer a file that had the same
    name as a file that already exists on the guest, we would just fail the
    transfer. This patch tries to match the behavior of the linux vdagent
    where we try to append an integer onto the name of the new file to make
    it unique. For example, if you tried to transfer 'file.doc' to the guest
    and that file already existed, it would try to create 'file (1).doc'
    instead. If that also failed, it would attempt 'file (2).doc', etc, up
    to 63.
    
    Resolves: rhbz#1410181
    Acked-by: Jonathon Jongsma <jjongsma at redhat.com>

diff --git a/vdagent/file_xfer.cpp b/vdagent/file_xfer.cpp
index f763ed3..de1aea1 100644
--- a/vdagent/file_xfer.cpp
+++ b/vdagent/file_xfer.cpp
@@ -28,6 +28,8 @@
 #endif // compiler specific definitions
 
 #include <stdio.h>
+#include <spice/macros.h>
+
 #include "file_xfer.h"
 #include "as_user.h"
 
@@ -99,13 +101,40 @@ void FileXfer::handle_start(VDAgentFileXferStartMessage* start,
 
     file_path[wlen++] = TEXT('\\');
     file_path[wlen] = TEXT('\0');
-    if((wlen = MultiByteToWideChar(CP_UTF8, 0, file_name, -1, file_path + wlen, MAX_PATH - wlen)) == 0){
-        vd_printf("failed converting file_name:%s to WideChar", file_name);
-        return;
+
+    const int MAX_ATTEMPTS = 64; // matches behavior of linux vdagent
+    const size_t POSTFIX_LEN = 6; // up to 2 digits in parentheses and final NULL: " (xx)"
+    char *extension = strrchr(file_name, '.');
+    if (!extension)
+        extension = strchr(file_name, 0);
+
+    for (int attempt = 0; attempt < MAX_ATTEMPTS; attempt++) {
+        char dest_filename[SPICE_N_ELEMENTS(file_name) + POSTFIX_LEN];
+        if (attempt == 0) {
+            strcpy(dest_filename, file_name);
+        } else {
+            sprintf(dest_filename, "%.*s (%d)%s", int(extension - file_name), file_name,
+                    attempt, extension);
+        }
+        if ((MultiByteToWideChar(CP_UTF8, 0, dest_filename, -1, file_path + wlen, MAX_PATH - wlen)) == 0) {
+            vd_printf("failed converting file_name:%s to WideChar", dest_filename);
+            return;
+        }
+        handle = CreateFile(file_path, GENERIC_WRITE, 0, NULL, CREATE_NEW, 0, NULL);
+        if (handle != INVALID_HANDLE_VALUE) {
+            break;
+        }
+
+        // If the file already exists, we can re-try with a new filename. If
+        // it's a different error, there's not much we can do.
+        if (GetLastError() != ERROR_FILE_EXISTS) {
+            vd_printf("Failed creating %ls %lu", file_path, GetLastError());
+            return;
+        }
     }
-    handle = CreateFile(file_path, GENERIC_WRITE, 0, NULL, CREATE_NEW, 0, NULL);
+
     if (handle == INVALID_HANDLE_VALUE) {
-        vd_printf("failed creating %ls %lu", file_path, GetLastError());
+        vd_printf("Failed creating %ls. More than 63 copies exist?", file_path);
         return;
     }
     task = new FileXferTask(handle, file_size, file_path);