Generating new page: retry on collision

1 files changed, 17 insertions, 9 deletions

diff --git a/whiteboard.cpp b/whiteboard.cpp
index 09674b5..b3367cf 100644
--- a/whiteboard.cpp
+++ b/whiteboard.cpp
@@ -36,23 +36,31 @@ namespace {
   return result & 0x7FFFFFFF;
  }
 
+ fs::path data_path;
+
  std::string generate_id()
  {
   static std::random_device r;
   static std::default_random_engine e1(r());
   static std::uniform_int_distribution<int> uniform_dist(0, 15);
 
-  std::string result;
-  for (int i = 0; i < 6; i++) {
-   char c{static_cast<char>('0' + uniform_dist(e1))};
-   if (c > '9')
-    c = c - '9' + 'a';
-   result.push_back(c);
+  // limit tries
+  for (int j = 0; j < 100000; j++) {
+   std::string result;
+   for (int i = 0; i < 6; i++) {
+    char c{static_cast<char>('0' + uniform_dist(e1))};
+    if (c > '9')
+     c = c - '9' + 'a';
+    result.push_back(c);
+   }
+   fs::path path{data_path / result};
+
+   if (!fs::exists(path))
+   return result;
   }
-  return result;
- }
 
- fs::path data_path;
+  return "endofcodes";
+ }
 
  void setFileById(const std::string& data, const std::string& id)
  {