From 11ae24f1f3fe39c1382c6cb37d3cddeeb757c91c Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Thu, 9 Sep 2021 12:19:46 +0200
Subject: [PATCH] Use std::string for monitor names

Makes it a lot easier to deal with the allocation of memory for the
string, avoiding any limits.
---
 vncviewer/MonitorArrangement.cxx | 52 ++++++++++++++++----------------
 vncviewer/MonitorArrangement.h   |  2 +-
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/vncviewer/MonitorArrangement.cxx b/vncviewer/MonitorArrangement.cxx
index 60637b95..a8813fe4 100644
--- a/vncviewer/MonitorArrangement.cxx
+++ b/vncviewer/MonitorArrangement.cxx
@@ -330,16 +330,16 @@ std::pair<int, int> MonitorArrangement::origin()
 
 std::string MonitorArrangement::description(int m)
 {
+  std::string name;
+  int x, y, w, h;
+  std::stringstream ss;
+
   assert(m < Fl::screen_count());
-  const size_t name_len = 1024;
-  char name[name_len] = {};
-  int bytes_written = get_monitor_name(m, name, name_len);
 
-  int x, y, w, h;
+  name = get_monitor_name(m);
   Fl::screen_xywh(x, y, w, h, m);
-  std::stringstream ss;
 
-  if (bytes_written > 0)
+  if (!name.empty())
     ss << name << " (" << w << "x" << h << ")";
   else
     ss << w << "x" << h;
@@ -357,7 +357,7 @@ static BOOL CALLBACK EnumDisplayMonitorsCallback(
 }
 #endif
 
-int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
+std::string MonitorArrangement::get_monitor_name(int m)
 {
 #if defined(WIN32)
   std::set<HMONITOR> sys_monitors;
@@ -384,23 +384,23 @@ int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
     if ((info.rcMonitor.bottom - info.rcMonitor.top) != h)
       continue;
 
-    return snprintf(name, name_len, "%.*s", (int)(name_len - 1), info.szDevice);
+    return info.szDevice;
   }
 
-  return -1;
+  return "";
 #elif defined(__APPLE__)
   CGDisplayCount count;
-  int bytes_written = 0;
   CGDirectDisplayID displays[16];
+  std::string name;
 
   if (CGGetActiveDisplayList(16, displays, &count) != kCGErrorSuccess)
-    return -1;
+    return "";
 
   if (count != (unsigned)Fl::screen_count())
-    return -1;
+    return "";
 
   if (m >= (int)count)
-    return -1;
+    return "";
 
   // Notice: Here we assume indices to be ordered the same as in FLTK (we rely on that in cocoa.mm as well).
   CGDirectDisplayID displayID = displays[m];
@@ -428,15 +428,17 @@ int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
       // with that encoding will fit.
       CFIndex localized_name_max_size = CFStringGetMaximumSizeForEncoding(localized_name_len, kCFStringEncodingUTF8) + 1;
 
-      if (name_len > (size_t)localized_name_max_size) {
+      if (localized_name_max_size != kCFNotFound) {
+        char *utf8_name = new char[localized_name_max_size];
         if (CFStringGetCString(
           /* ref = */ localized_name,
-          /* dest = */ name,
-          /* dest_len = */ name_len,
+          /* dest = */ utf8_name,
+          /* dest_len = */ localized_name_max_size,
           /* encoding = */ kCFStringEncodingUTF8))
         {
-          bytes_written = strlen(name);
+          name = utf8_name;
         }
+        delete [] utf8_name;
       }
     }
 
@@ -444,7 +446,8 @@ int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
   }
 
   CFRelease(info);
-  return bytes_written;
+
+  return name;
 
 #else
 #if defined (HAVE_XRANDR)
@@ -457,13 +460,13 @@ int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
 
   if (!XQueryExtension(fl_display, "RANDR", &xi_major, &ev, &err)) {
     vlog.info(_("Failed to get monitor name because X11 RandR could not be found"));
-    return -1;
+    return "";
   }
 
   XRRScreenResources *res = XRRGetScreenResources(fl_display, DefaultRootWindow(fl_display));
   if (!res) {
     vlog.error(_("Failed to get system monitor configuration"));
-    return -1;
+    return "";
   }
 
   for (int i = 0; i < res->ncrtc; i++) {
@@ -487,18 +490,15 @@ int MonitorArrangement::get_monitor_name(int m, char name[], size_t name_len)
           continue;
         }
 
-        if (strlen(output->name) >= name_len)
-          return -1;
-
-        return snprintf(name, name_len, "%.*s", (int)name_len, output->name);
+        return output->name;
       }
     }
   }
 
-  return -1;
+  return "";
 
 #endif // !HAVE_XRANDR
-  return 0;
+  return "";
 #endif
 }
 
diff --git a/vncviewer/MonitorArrangement.h b/vncviewer/MonitorArrangement.h
index e69198b6..fa8741f3 100644
--- a/vncviewer/MonitorArrangement.h
+++ b/vncviewer/MonitorArrangement.h
@@ -73,7 +73,7 @@ private:
 
   // Get a textual description of the given monitor.
   std::string description(int m);
-  int get_monitor_name(int m, char name[], size_t name_len);
+  std::string get_monitor_name(int m);
 
   static int fltk_event_handler(int event);
   static void monitor_pressed(Fl_Widget *widget, void *user_data);
-- 
2.39.5