Use SkSet to fix issue when pdf generates an exp number of resources.
The problem fixed - http://code.google.com/p/skia/issues/detail?id=940 - is that getResources will recursively obtain all child resource recursively without checking for duplicates.
If we have lots of duplicates, then we try to build a very large vector (exponential with the number of nodes usually) and sooner or later we end up using too much memory and crash.
A possible solution could have been to make sure resources do not have duplicates, but that requirement is impractical, and it this leaves the solution fragile, if there is any issue in the tree, we crash.
When we emit the pdf, the large number of duplicates is not an issue, because SkPDFCatalog::addObject will deal with duplicates.
I have run the gm with --config pdf, and the images are 100% same bits, while the pdfs have the same size but some very small changes, the order of some objects.
Review URL: https://codereview.appspot.com/6744050
git-svn-id: http://skia.googlecode.com/svn/trunk@7883 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pdf/SkPDFDocument.cpp b/src/pdf/SkPDFDocument.cpp
index c7266d8..fc09286 100644
--- a/src/pdf/SkPDFDocument.cpp
+++ b/src/pdf/SkPDFDocument.cpp
@@ -14,21 +14,13 @@
#include "SkPDFPage.h"
#include "SkPDFTypes.h"
#include "SkStream.h"
+#include "SkTSet.h"
-// Add the resources, starting at firstIndex to the catalog, removing any dupes.
-// A hash table would be really nice here.
-static void addResourcesToCatalog(int firstIndex, bool firstPage,
- SkTDArray<SkPDFObject*>* resourceList,
- SkPDFCatalog* catalog) {
- for (int i = firstIndex; i < resourceList->count(); i++) {
- int index = resourceList->find((*resourceList)[i]);
- if (index != i) {
- (*resourceList)[i]->unref();
- resourceList->removeShuffle(i);
- i--;
- } else {
- catalog->addObject((*resourceList)[i], firstPage);
- }
+static void addResourcesToCatalog(bool firstPage,
+ SkTSet<SkPDFObject*>* resourceSet,
+ SkPDFCatalog* catalog) {
+ for (int i = 0; i < resourceSet->count(); i++) {
+ catalog->addObject((*resourceSet)[i], firstPage);
}
}
@@ -57,11 +49,12 @@
SkPDFDocument::SkPDFDocument(Flags flags)
: fXRefFileOffset(0),
- fSecondPageFirstResourceIndex(0),
fTrailerDict(NULL) {
fCatalog.reset(new SkPDFCatalog(flags));
fDocCatalog = SkNEW_ARGS(SkPDFDict, ("Catalog"));
fCatalog->addObject(fDocCatalog, true);
+ fFirstPageResources = NULL;
+ fOtherPageResources = NULL;
}
SkPDFDocument::~SkPDFDocument() {
@@ -73,11 +66,14 @@
fPageTree[i]->clear();
}
fPageTree.safeUnrefAll();
- fPageResources.safeUnrefAll();
+ fFirstPageResources->safeUnrefAll();
+ fOtherPageResources->safeUnrefAll();
fSubstitutes.safeUnrefAll();
fDocCatalog->unref();
SkSafeUnref(fTrailerDict);
+ SkDELETE(fFirstPageResources);
+ SkDELETE(fOtherPageResources);
}
bool SkPDFDocument::emitPDF(SkWStream* stream) {
@@ -90,6 +86,9 @@
}
}
+ fFirstPageResources = SkNEW(SkTSet<SkPDFObject*>);
+ fOtherPageResources = SkNEW(SkTSet<SkPDFObject*>);
+
// We haven't emitted the document before if fPageTree is empty.
if (fPageTree.isEmpty()) {
SkPDFDict* pageTreeRoot;
@@ -108,15 +107,35 @@
*/
bool firstPage = true;
+ /* The references returned in newResources are transfered to
+ * fFirstPageResources or fOtherPageResources depending on firstPage and
+ * knownResources doesn't have a reference but just relies on the other
+ * two sets to maintain a reference.
+ */
+ SkTSet<SkPDFObject*> knownResources;
+
+ // mergeInto returns the number of duplicates.
+ // If there are duplicates, there is a bug and we mess ref counting.
+ int duplicates = 0;
+ knownResources.mergeInto(*fFirstPageResources);
for (int i = 0; i < fPages.count(); i++) {
- int resourceCount = fPageResources.count();
- fPages[i]->finalizePage(fCatalog.get(), firstPage, &fPageResources);
- addResourcesToCatalog(resourceCount, firstPage, &fPageResources,
- fCatalog.get());
- if (i == 0) {
+ if (i == 1) {
firstPage = false;
- fSecondPageFirstResourceIndex = fPageResources.count();
+ duplicates = knownResources.mergeInto(*fOtherPageResources);
}
+ SkTSet<SkPDFObject*> newResources;
+ fPages[i]->finalizePage(
+ fCatalog.get(), firstPage, knownResources, &newResources);
+ addResourcesToCatalog(firstPage, &newResources, fCatalog.get());
+ if (firstPage) {
+ duplicates = fFirstPageResources->mergeInto(newResources);
+ } else {
+ duplicates = fOtherPageResources->mergeInto(newResources);
+ }
+ SkASSERT(duplicates == 0);
+
+ duplicates = knownResources.mergeInto(newResources);
+ SkASSERT(duplicates == 0);
}
// Build font subsetting info before proceeding.
@@ -128,8 +147,8 @@
fileOffset += fCatalog->setFileOffset(fPages[0], fileOffset);
fileOffset += fPages[0]->getPageSize(fCatalog.get(),
(size_t) fileOffset);
- for (int i = 0; i < fSecondPageFirstResourceIndex; i++) {
- fileOffset += fCatalog->setFileOffset(fPageResources[i],
+ for (int i = 0; i < fFirstPageResources->count(); i++) {
+ fileOffset += fCatalog->setFileOffset((*fFirstPageResources)[i],
fileOffset);
}
// Add the size of resources of substitute objects used on page 1.
@@ -147,11 +166,9 @@
fileOffset += fPages[i]->getPageSize(fCatalog.get(), fileOffset);
}
- for (int i = fSecondPageFirstResourceIndex;
- i < fPageResources.count();
- i++) {
- fileOffset += fCatalog->setFileOffset(fPageResources[i],
- fileOffset);
+ for (int i = 0; i < fOtherPageResources->count(); i++) {
+ fileOffset += fCatalog->setFileOffset(
+ (*fOtherPageResources)[i], fileOffset);
}
fileOffset += fCatalog->setSubstituteResourcesOffsets(fileOffset,
@@ -163,8 +180,8 @@
fDocCatalog->emitObject(stream, fCatalog.get(), true);
fPages[0]->emitObject(stream, fCatalog.get(), true);
fPages[0]->emitPage(stream, fCatalog.get());
- for (int i = 0; i < fSecondPageFirstResourceIndex; i++) {
- fPageResources[i]->emit(stream, fCatalog.get(), true);
+ for (int i = 0; i < fFirstPageResources->count(); i++) {
+ (*fFirstPageResources)[i]->emit(stream, fCatalog.get(), true);
}
fCatalog->emitSubstituteResources(stream, true);
// TODO(vandebo): Support linearized format
@@ -181,10 +198,8 @@
fPages[i]->emitPage(stream, fCatalog.get());
}
- for (int i = fSecondPageFirstResourceIndex;
- i < fPageResources.count();
- i++) {
- fPageResources[i]->emit(stream, fCatalog.get(), true);
+ for (int i = 0; i < fOtherPageResources->count(); i++) {
+ (*fOtherPageResources)[i]->emit(stream, fCatalog.get(), true);
}
fCatalog->emitSubstituteResources(stream, false);