diff options
Diffstat (limited to 'cpp/src/Ice/GC.cpp')
| -rwxr-xr-x | cpp/src/Ice/GC.cpp | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/cpp/src/Ice/GC.cpp b/cpp/src/Ice/GC.cpp index 938ee6fab56..463eff13fd4 100755 --- a/cpp/src/Ice/GC.cpp +++ b/cpp/src/Ice/GC.cpp @@ -163,10 +163,11 @@ IceInternal::GC::collectGarbage() // // gcObjects contains the set of class instances that have at least one member of class type, // that is, gcObjects contains all those instances that can point at other instances. - // Call this the the candiate set. + // Call this the candidate set. // Build a multiset of instances that are immediately (not recursively) reachable from instances - // in the candidate set. This adds leaf nodes (class instances that are pointed at, but cannot - // point at anything themselves) to the multiset. + // in the candidate set. This adds adds all immediately reachable nodes to the reachable set, but + // does not add nodes that cannot participate in a cycle (class instances that are pointed at, but cannot + // point at anything themselves because they have no class members) to the multiset. // GCObjectMultiSet reachable; { @@ -177,7 +178,7 @@ IceInternal::GC::collectGarbage() } // - // Create a map of reference counts. + // Create a map of reference counts of all objects in the reachable set. // typedef map<GCShared*, int> ObjectCounts; ObjectCounts counts; @@ -188,7 +189,7 @@ IceInternal::GC::collectGarbage() pos = counts.find(*i); // - // If this instance is not in the counts set yet, insert it with its reference count - 1; + // If this instance is not in the counts map yet, insert it with its reference count - 1; // otherwise, decrement its reference count. // if(pos == counts.end()) @@ -203,8 +204,8 @@ IceInternal::GC::collectGarbage() } // - // Any instances with a ref count > 0 are referenced from outside the set of class instances (and therefore - // reachable from the program, for example, via Ptr variable on the stack). Remove these instances + // Any instances with a ref count > 0 are referenced from outside the reachable class instances (and + // therefore reachable from the program, for example, via Ptr variable on the stack). Remove these instances // (and all instances reachable from them) from the overall set of objects. // { @@ -230,7 +231,15 @@ IceInternal::GC::collectGarbage() ObjectCounts::const_iterator i; for(i = counts.begin(); i != counts.end(); ++i) { - i->first->__gcClear(); // Decrement ref count of objects pointed at by this object. + // + // For classes with members that point at potentially-cyclic instances, __gcClear() + // decrements the reference count of those instances and clears the + // corrsponding Ptr members. + // For classes that cannot be part of a cycle (because they do not contain class members) + // and are therefore true leaves, __gcClear() assigns 0 to the corresponding class member, + // which either decrements the ref count or, if it reaches zero, deletes the instance as usual. + // + i->first->__gcClear(); } for(i = counts.begin(); i != counts.end(); ++i) { @@ -255,7 +264,7 @@ IceInternal::GC::collectGarbage() counts.clear(); { - Monitor<Mutex>::Lock sync2(*this); + Monitor<Mutex>::Lock sync(*this); _collecting = false; } |