From 6755a86734176caa1a3c38ad6db5bc3a01be8505 Mon Sep 17 00:00:00 2001 From: Jay Berkenbilt Date: Sun, 6 Jun 2010 18:03:21 +0000 Subject: comment on memory leak fix git-svn-id: svn+q:///qpdf/trunk@979 71b93d88-0707-0410-a8cf-f5a4172ac649 --- libqpdf/QPDF.cc | 14 ++++++++++++++ libqpdf/QPDFObjectHandle.cc | 4 ++++ 2 files changed, 18 insertions(+) diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc index f68efc83..cbc2450c 100644 --- a/libqpdf/QPDF.cc +++ b/libqpdf/QPDF.cc @@ -277,6 +277,20 @@ QPDF::QPDF() : QPDF::~QPDF() { + // If two objects are mutually referential (through each object + // having an array or dictionary that contains an indirect + // reference to the other), the circular references in the + // PointerHolder objects will prevent the objects from being + // deleted. Walk through all objects in the object cache, which + // is those objects that we read from the file, and break all + // resolved references. At this point, obviously no one is still + // using the QPDF object, but we'll explicitly clear the xref + // table anyway just to prevent any possibility of resolve() + // succeeding. Note that we can't break references like this at + // any time when the QPDF object is active. If we do, the next + // reference will reread the object from the file, which would + // have the effect of undoing any modifications that may have been + // made to any of the objects. this->xref_table.clear(); for (std::map::iterator iter = this->obj_cache.begin(); iter != obj_cache.end(); ++iter) diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc index 022c9e05..677c2347 100644 --- a/libqpdf/QPDFObjectHandle.cc +++ b/libqpdf/QPDFObjectHandle.cc @@ -44,6 +44,10 @@ QPDFObjectHandle::QPDFObjectHandle(QPDFObject* data) : void QPDFObjectHandle::releaseResolved() { + // Recursively break any resolved references to indirect objects. + // Do not cross over indirect object boundaries to avoid an + // infinite loop. This method may only be called during final + // destruction. See comments in QPDF::~QPDF(). if (isIndirect()) { if (this->obj.getPointer()) -- cgit v1.2.3-54-g00ecf