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Thread safety implementation using locking #836

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Merged
johnhaley81 merged 20 commits into from
Jan 12, 2016
Merged

Thread safety implementation using locking #836

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f07b098
Add LockMaster
srajko Dec 17, 2015
64ba08a
Use LockMaster for sync and async functions
srajko Dec 17, 2015
cb92954
Move template specializations out of class definition
srajko Dec 17, 2015
81740e3
Add repo locking for commits
srajko Dec 17, 2015
12eca23
Remove use of auto
srajko Dec 17, 2015
7579e3a
Add temporary unlock during callbacks
srajko Dec 17, 2015
7d31f52
Test callback deadlock
srajko Dec 18, 2015
908b8b5
Clean up mutexes
srajko Dec 18, 2015
c33fa10
Ensure mutexes are locked all at the same time
srajko Dec 18, 2015
65a998d
Add opt-in / opt-out mechanism for thread safety
srajko Dec 18, 2015
040a4ee
Fix uv_mutex_trylock response handling
srajko Dec 23, 2015
5efab3f
Remove use of shared_ptr
srajko Dec 30, 2015
4b506f7
Address c++11 warnings
srajko Dec 31, 2015
7257e5e
Move LockMaster to its own files
srajko Dec 31, 2015
fb4603d
Reorganize and clean up code
srajko Jan 1, 2016
90d8073
Use auto, range-based for loops, and for_each
srajko Jan 4, 2016
ab3d2da
Use ObjectInfo instead of pair for readability
srajko Jan 4, 2016
dbce34f
Initialize LockMaster before using it
srajko Jan 5, 2016
1c6ea17
Remove unused else
srajko Jan 6, 2016
7a5a37f
Make thread safety enable / disable more robust to toggling
srajko Jan 6, 2016
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Use ObjectInfo instead of pair for readability
  • Loading branch information
@srajko
srajko committed Jan 4, 2016
commit ab3d2da58d6d2e64fb8eeadb15d2d431bd15d781
34 changes: 22 additions & 12 deletions generate/templates/manual/src/lock_master.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -7,13 +7,24 @@

#include "../include/lock_master.h"

// information about a lockable object
// - the mutex used to lock it and the number of outstanding locks
struct ObjectInfo {
uv_mutex_t *mutex;
unsigned useCount;

ObjectInfo(uv_mutex_t *mutex, unsigned useCount)
: mutex(mutex), useCount(useCount)
{}
};

// LockMaster implementation details
// implemented in a separate class to keep LockMaster opaque
class LockMasterImpl {
// STATIC variables / methods

// A map from objects that are locked (or were locked), to information on their mutex
static std::map<const void *, std::pair<uv_mutex_t *, unsigned> > mutexes;
static std::map<const void *, ObjectInfo> mutexes;
// A mutex used for the mutexes map
static uv_mutex_t mapMutex;

Expand Down Expand Up @@ -64,7 +75,7 @@ class LockMasterImpl {
void Unlock(bool releaseMutexes);
};

std::map<const void *, std::pair<uv_mutex_t *, unsigned> > LockMasterImpl::mutexes;
std::map<const void *, ObjectInfo> LockMasterImpl::mutexes;
uv_mutex_t LockMasterImpl::mapMutex;
uv_key_t LockMasterImpl::currentLockMasterKey;
uv_async_t LockMasterImpl::cleanupMutexesHandle;
Expand All @@ -81,12 +92,11 @@ void LockMasterImpl::CleanupMutexes(uv_async_t *async) {

for (auto it = mutexes.begin(); it != mutexes.end(); )
{
uv_mutex_t *mutex = it->second.first;
unsigned use_count = it->second.second;
// if the mutex is only referenced by the mutexes map,
// we can destroy it (because any LockMaster that is using the mutex would
// hold it in its objectMutexes)
if (!use_count) {
uv_mutex_t *mutex = it->second.mutex;
unsigned useCount = it->second.useCount;
// if the mutex is not used by any LockMasters,
// we can destroy it
if (!useCount) {
uv_mutex_destroy(mutex);
free(mutex);
auto to_erase = it;
Expand Down Expand Up @@ -117,14 +127,14 @@ std::vector<uv_mutex_t *> LockMasterImpl::GetMutexes(int useCountDelta) {
mutexIt = mutexes.insert(
std::make_pair(
object,
std::make_pair((uv_mutex_t *)malloc(sizeof(uv_mutex_t)), 0U)
ObjectInfo((uv_mutex_t *)malloc(sizeof(uv_mutex_t)), 0U)
)
).first;
uv_mutex_init(mutexIt->second.first);
uv_mutex_init(mutexIt->second.mutex);
}

objectMutexes.push_back(mutexIt->second.first);
mutexIt->second.second += useCountDelta;
objectMutexes.push_back(mutexIt->second.mutex);
mutexIt->second.useCount += useCountDelta;
}
}

Expand Down