From 447458ca25bef556a4347fc395b68da9a09a2a3b Mon Sep 17 00:00:00 2001
From: EntireTwix <willkatz.dev@gmail.com>
Date: Fri, 9 Apr 2021 02:16:50 -0700
Subject: [PATCH] :racehorse: reworked locking based on frequency of fucking
 called

---
 include/bank.hpp | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/include/bank.hpp b/include/bank.hpp
index 768151a..81770b8 100644
--- a/include/bank.hpp
+++ b/include/bank.hpp
@@ -18,20 +18,23 @@ private:
         users;
 
     /**
-     * @brief any function that WRITES to users in a way that CHANGES its SIZE OR takes MORE THEN ONE OPERATION must share lock this lock 
-     * as to be stopped when saving, as saving data must not be corrupted. one operation writes that done modify size aswell as reads are 
-     * permitted while saving so they do not have to share this lock
+     * @brief size_lock should be grabbed if the operation MODIFIES the size (unique) or READS from the users where size changes could distort (shared)
      * 
      */
     std::shared_mutex size_lock;
-    std::shared_mutex bal_lock;
+
+    /**
+     * @brief send_funds_l should be grabbed if balances are being MODIFIED (shared) or if an operation needs to READ without the intermediary states that sendfunds has (unique)
+     * 
+     */
+    std::shared_mutex send_funds_l;
 
 public:
     std::string admin_pass;
 
     bool AddUser(const std::string &name, std::string &&init_pass)
     {
-        std::shared_lock<std::shared_mutex> lock{size_lock};
+        std::unique_lock<std::shared_mutex> lock{size_lock};
         return users.try_emplace_l(
             name, [](User &) {}, std::move(init_pass));
     }
@@ -40,7 +43,7 @@ public:
         bool state = (admin_pass == attempt);
         if (state)
         {
-            std::shared_lock<std::shared_mutex> lock{size_lock};
+            std::unique_lock<std::shared_mutex> lock{size_lock};
             state = users.try_emplace_l(
                 name, [](User &) {}, init_bal, std::move(init_pass));
         }
@@ -49,12 +52,12 @@ public:
 
     bool DelUser(const std::string &name, const std::string &attempt)
     {
-        std::shared_lock<std::shared_mutex> lock{size_lock};
+        std::unique_lock<std::shared_mutex> lock{size_lock};
         return users.erase_if(name, [&attempt](const User &u) { return (attempt == u.password); });
     }
     bool AdminDelUser(const std::string &name, const std::string &attempt)
     {
-        std::shared_lock<std::shared_mutex> lock{size_lock};
+        std::unique_lock<std::shared_mutex> lock{size_lock};
         return users.erase_if(name, [this, &attempt](const User &) { return (admin_pass == attempt); });
     }
 
@@ -69,7 +72,7 @@ public:
 
         //if A exists, A can afford it, and A's password matches
         bool state = false;
-        std::shared_lock<std::shared_mutex> lock{bal_lock}; //because SendFunds requires 3 locking operations
+        std::shared_lock<std::shared_mutex> lock{send_funds_l}; //because SendFunds requires 3 locking operations
         users.modify_if(a_name, [&state, amount, &attempt](User &a) {
             if (state = (a.balance >= amount) && (a.password == attempt), state)
             {
@@ -143,7 +146,7 @@ public:
     {
         Json::Value temp;
         Json::UInt i = 0;
-        std::unique_lock<std::shared_mutex> lock{size_lock};
+        std::shared_lock<std::shared_mutex> lock{size_lock}; //gives readers of users the lock
         for (const auto &u : users)
         {
             //we know it contains this key but we call this func to grab mutex
@@ -162,7 +165,8 @@ public:
 
         //loading info into json temp
         {
-            std::scoped_lock<std::shared_mutex, std::shared_mutex> lock{size_lock, bal_lock}; //grabbing it from any busy add/del/sendfunds opperations
+            std::shared_lock<std::shared_mutex> lock{size_lock};          //gives readers of users the lock
+            std::unique_lock<std::shared_mutex> halt_funds{send_funds_l}; //halts all send fund requests
             for (const auto &u : users)
             {
                 //we know it contains this key but we call this func to grab mutex