From 7796278140357a8d5b53693901e9f4c722a35b07 Mon Sep 17 00:00:00 2001
From: Christopher Jones <chrisdjones15@gmail.com>
Date: Fri, 4 Dec 2020 11:05:17 -0600
Subject: [PATCH] Use read/write locks when accessing dictionary
---
.../include/Evaluator/detail/Evaluator.h | 5 +-
DDParsers/src/Evaluator/Evaluator.cpp | 59 +++++++++++++++----
2 files changed, 51 insertions(+), 13 deletions(-)
diff --git a/DDParsers/include/Evaluator/detail/Evaluator.h b/DDParsers/include/Evaluator/detail/Evaluator.h
index 82da50cb0..62d840ca9 100644
--- a/DDParsers/include/Evaluator/detail/Evaluator.h
+++ b/DDParsers/include/Evaluator/detail/Evaluator.h
@@ -133,7 +133,7 @@ namespace dd4hep {
* @see error_position
* @see print_error
*/
- EvalStatus evaluate(const char* expression);
+ EvalStatus evaluate(const char* expression) const;
/**
* Adds to the dictionary a string constant
@@ -149,7 +149,7 @@ namespace dd4hep {
*
* @param name name of the variable.
*/
- std::pair<const char*, int> getEnviron(const char* name);
+ std::pair<const char*, int> getEnviron(const char* name) const;
/**
* Adds to the dictionary a variable with given value.
@@ -306,7 +306,6 @@ namespace dd4hep {
*/
void setStdMath();
-
Struct* imp {0}; // private data
Object(const Object &) = delete; // copy constructor is not allowed
Object & operator=(const Object &) = delete; // assignment is not allowed
diff --git a/DDParsers/src/Evaluator/Evaluator.cpp b/DDParsers/src/Evaluator/Evaluator.cpp
index 449a3deb4..e94f838af 100644
--- a/DDParsers/src/Evaluator/Evaluator.cpp
+++ b/DDParsers/src/Evaluator/Evaluator.cpp
@@ -9,6 +9,7 @@
#include <cmath> // for pow()
#include <sstream>
#include <mutex>
+#include <condition_variable>
#include <cctype>
#include <cerrno>
#include <cstring>
@@ -60,7 +61,45 @@ typedef hash_map<string,Item> dic_type;
/// Internal expression evaluator helper class
struct EVAL::Object::Struct {
+ struct ReadLock {
+ ReadLock(Struct* s): theStruct(s), theLg(s->theLock) {
+ while(theStruct->theWriterWaiting)
+ theStruct->theCond.wait(theLg);
+ ++theStruct->theReadersWaiting;
+ }
+
+ ReadLock(const ReadLock&) = delete;
+ ~ReadLock() {
+ --theStruct->theReadersWaiting;
+ while(theStruct->theReadersWaiting > 0)
+ theStruct->theCond.wait(theLg);
+ theStruct->theCond.notify_one();
+ }
+ Struct* theStruct;
+ std::unique_lock<std::mutex> theLg;
+
+ };
+ struct WriteLock {
+ WriteLock(Struct* s): theStruct(s), theLg(s->theLock) {
+ while(theStruct->theWriterWaiting)
+ theStruct->theCond.wait(theLg);
+ }
+ WriteLock(const WriteLock&) = delete;
+ ~WriteLock() {
+ theStruct->theWriterWaiting = true;
+ while(theStruct->theReadersWaiting > 0)
+ theStruct->theCond.wait(theLg);
+ theStruct->theWriterWaiting = false;
+ theStruct->theCond.notify_all();
+ }
+ Struct* theStruct;
+ std::unique_lock<std::mutex> theLg;
+ };
+
dic_type theDictionary;
+ int theReadersWaiting = 0;
+ bool theWriterWaiting = false;
+ std::condition_variable theCond;
std::mutex theLock;
};
@@ -585,7 +624,7 @@ static int setItem(const char * prefix, const char * name,
// A D D I T E M T O T H E D I C T I O N A R Y
string item_name = prefix + string(pointer,n);
- std::lock_guard<std::mutex> guard(imp->theLock);
+ EVAL::Object::Struct::WriteLock guard(imp);
dic_type::iterator iter = imp->theDictionary.find(item_name);
if (iter != imp->theDictionary.end()) {
iter->second = item;
@@ -659,10 +698,10 @@ Evaluator::Object::~Object() {
}
//---------------------------------------------------------------------------
-Evaluator::Object::EvalStatus Evaluator::Object::evaluate(const char * expression) {
+Evaluator::Object::EvalStatus Evaluator::Object::evaluate(const char * expression) const {
EvalStatus s;
if (expression != 0) {
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::ReadLock guard(imp);
s.theStatus = engine(expression,
expression+strlen(expression)-1,
s.theResult,
@@ -709,7 +748,7 @@ int Evaluator::Object::setEnviron(const char* name, const char* value) {
item.expression = value;
item.function = 0;
item.variable = 0;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::WriteLock guard(imp);
dic_type::iterator iter = imp->theDictionary.find(item_name);
if (iter != imp->theDictionary.end()) {
iter->second = item;
@@ -725,9 +764,9 @@ int Evaluator::Object::setEnviron(const char* name, const char* value) {
}
//---------------------------------------------------------------------------
-std::pair<const char*,int> Evaluator::Object::getEnviron(const char* name) {
+std::pair<const char*,int> Evaluator::Object::getEnviron(const char* name) const {
string item_name = name;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::ReadLock guard(imp);
dic_type::iterator iter = imp->theDictionary.find(item_name);
if (iter != imp->theDictionary.end()) {
return std::make_pair(iter->second.expression.c_str(), EVAL::OK);
@@ -781,7 +820,7 @@ bool Evaluator::Object::findVariable(const char * name) const {
if (name == 0 || *name == '\0') return false;
const char * pointer; int n; REMOVE_BLANKS;
if (n == 0) return false;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::ReadLock guard(imp);
return
(imp->theDictionary.find(string(pointer,n)) == imp->theDictionary.end()) ?
false : true;
@@ -793,7 +832,7 @@ bool Evaluator::Object::findFunction(const char * name, int npar) const {
if (npar < 0 || npar > MAX_N_PAR) return false;
const char * pointer; int n; REMOVE_BLANKS;
if (n == 0) return false;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::ReadLock guard(imp);
return (imp->theDictionary.find(sss[npar]+string(pointer,n)) ==
imp->theDictionary.end()) ? false : true;
}
@@ -803,7 +842,7 @@ void Evaluator::Object::removeVariable(const char * name) {
if (name == 0 || *name == '\0') return;
const char * pointer; int n; REMOVE_BLANKS;
if (n == 0) return;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::WriteLock guard(imp);
imp->theDictionary.erase(string(pointer,n));
}
@@ -813,7 +852,7 @@ void Evaluator::Object::removeFunction(const char * name, int npar) {
if (npar < 0 || npar > MAX_N_PAR) return;
const char * pointer; int n; REMOVE_BLANKS;
if (n == 0) return;
- std::lock_guard<std::mutex> guard(imp->theLock);
+ Struct::WriteLock guard(imp);
imp->theDictionary.erase(sss[npar]+string(pointer,n));
}
--
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