Consider this PR as a cosmetic one.
Creating Status class object in the code is not so clear. It is not so obvious that defatult costructed Status is success. Also it is not obvious that status with zero code is success and non-zero is failure.
To fix it I created 2 static methods to make construction of some particular status clear to reader.
* Use assert to check code in Status::failure in debut mode
* Rename success_code constant to kSuccessCode
according to style guide
If the shell history file does not contain a timestamps for the lines
osquery will miss the time in rows and will show an confusing error
about attempt to convert empty string to INTEGER.
```
% head -n 3 ~/.zsh_history
ls
cd source
ls
```
```
osquery> select * from shell_history limit 1;
I0621 11:56:37.804193 2629124992 virtual_table.cpp:292] Error casting time () to INTEGER
+------------+------+---------+-------------------------------+
| uid | time | command | history_file |
+------------+------+---------+-------------------------------+
| 1868255265 | | exit | /home/akindyakov/.zsh_history |
+------------+------+---------+-------------------------------+
```
So, default value for the time in shell history can solve the problem.
osquery itself does not care about unicode validity in table columns,
just takes it "as is". It definetely makes sense, because it could be broken.
But thrift extensions interface for python do it.
If, for instance, shell history contains broken unicode test `python_test_example_queries`
will fail.
```bash
% sed -n '5277p' < ~/.zsh_history | xxd -b [146]
00000000: 11000011 10000011 10111111 01101100 01110011 00001010 ...ls.
```
* dispatcher race conditions
dispatcher had 2 race condition.
In joinServices it was accessing service_threads_ with different lock(join_lock). However, if by that time new service was added baad things would happen :) .
Also dispatcher was accessing services_.size() without the lock. ( If by that time service was removed or joined bad things would happen)
* InterruptableRunnable RunnerInterruptPoint redesign
There were several inefficiencies in the old version of RunnerInterruptPoint and InterruptableRunnable.
1) RunnerInterruptPoint was throwing the exception when interrupted, however, the exception was always ignored.
2) InterruptableRunnable used the read-write lock, however only write lock was used.
3) InterruptableRunnable InterruptableRunnable, stored almost similar variable stop_, interrupted_.
4) std::atomic<bool> interrupted_ was used with locks, even though it was accessed by default safest access mode memory_order_seq_cst. So no additional cache invalidation was needed.
5) InterruptableRunnable contained code(in method interrupted() and variables bypass_check_, checked) just for testing. Which was slowing down method interrupted().
6) Some more confusing things. notify_all was not needed, as only one thread could be waiting for the conditional variable. RunnerInterruptPoint:: pause(void) looks ambiguous and that's why was not used anywhere.
I resolved all these problems by merging InterruptableRunnable and RunnerInterruptPoint into the InterruptableRunnable.
1) No use of the exception.
2) 4) Simple mutex, which is only used for pauseMilli. InterruptableRunnable::interrupted and InterruptableRunnable::interrupt function lock-free.
3) Single variable interrupted_.
5) Made InterruptableRunnable::interrupt virtual. Tests override interrupt to make things testable.
6) change to notify_one and removed pause without the specific time.
split(string,string,size_t) contained bug, it was joining on every delimiter, which would result to unusual outcome. However, test could not detect this problem as delim.size() was 1. It turned out, that this split is not used anywhere having delim.size() > 1, so completely fixing bug by changing signature of the method to split(string,char,size_t)
