From d3a2009d75eac3cda442f545ef0865afae7b35cf Mon Sep 17 00:00:00 2001 From: npm Date: Wed, 26 Oct 2016 11:03:43 -0700 Subject: Traverse PDF page tree only once in CPDF_Document Try 2: main fix was recursively popping elements from the stack. Since the Traverse method can be called on non-root nodes from GetPage(), we have to make sure to properly update the parents. Try 1 at https://codereview.chromium.org/2414423002/ In our current implementation of CPDF_Document::GetPage, we traverse the PDF page tree until we find the index we are looking for. This is slow when we do calls GetPage(0), GetPage(1), ... since in this case the page tree will be traversed n times if there are n pages. This CL makes sure the page tree is only traversed once. Time to load the PDF from the bug below in chrome official build: Before this CL: around 1 minute 25 seconds After this CL: around 4 seconds BUG=chromium:638513 Review-Url: https://codereview.chromium.org/2442403002 --- core/fpdfapi/parser/cpdf_document.cpp | 256 +++++++++++++++++++--------------- core/fpdfapi/parser/cpdf_document.h | 21 ++- 2 files changed, 162 insertions(+), 115 deletions(-) diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp index c5f64a790c..f548a26038 100644 --- a/core/fpdfapi/parser/cpdf_document.cpp +++ b/core/fpdfapi/parser/cpdf_document.cpp @@ -8,6 +8,7 @@ #include #include +#include #include #include "core/fpdfapi/cpdf_modulemgr.h" @@ -240,83 +241,6 @@ void InsertWidthArray1(CFX_Font* pFont, InsertWidthArrayImpl(widths, size, pWidthArray); } -int InsertDeletePDFPage(CPDF_Document* pDoc, - CPDF_Dictionary* pPages, - int nPagesToGo, - CPDF_Dictionary* pPage, - FX_BOOL bInsert, - std::set* pVisited) { - CPDF_Array* pKidList = pPages->GetArrayFor("Kids"); - if (!pKidList) - return -1; - - for (size_t i = 0; i < pKidList->GetCount(); i++) { - CPDF_Dictionary* pKid = pKidList->GetDictAt(i); - if (pKid->GetStringFor("Type") == "Page") { - if (nPagesToGo == 0) { - if (bInsert) { - pKidList->InsertAt(i, new CPDF_Reference(pDoc, pPage->GetObjNum())); - pPage->SetReferenceFor("Parent", pDoc, pPages->GetObjNum()); - } else { - pKidList->RemoveAt(i); - } - pPages->SetIntegerFor( - "Count", pPages->GetIntegerFor("Count") + (bInsert ? 1 : -1)); - return 1; - } - nPagesToGo--; - } else { - int nPages = pKid->GetIntegerFor("Count"); - if (nPagesToGo < nPages) { - if (pdfium::ContainsKey(*pVisited, pKid)) - return -1; - - pdfium::ScopedSetInsertion insertion(pVisited, pKid); - if (InsertDeletePDFPage(pDoc, pKid, nPagesToGo, pPage, bInsert, - pVisited) < 0) { - return -1; - } - pPages->SetIntegerFor( - "Count", pPages->GetIntegerFor("Count") + (bInsert ? 1 : -1)); - return 1; - } - nPagesToGo -= nPages; - } - } - return 0; -} - -int InsertNewPage(CPDF_Document* pDoc, - int iPage, - CPDF_Dictionary* pPageDict, - CFX_ArrayTemplate& pageList) { - CPDF_Dictionary* pRoot = pDoc->GetRoot(); - CPDF_Dictionary* pPages = pRoot ? pRoot->GetDictFor("Pages") : nullptr; - if (!pPages) - return -1; - - int nPages = pDoc->GetPageCount(); - if (iPage < 0 || iPage > nPages) - return -1; - - if (iPage == nPages) { - CPDF_Array* pPagesList = pPages->GetArrayFor("Kids"); - if (!pPagesList) { - pPagesList = new CPDF_Array; - pPages->SetFor("Kids", pPagesList); - } - pPagesList->Add(new CPDF_Reference(pDoc, pPageDict->GetObjNum())); - pPages->SetIntegerFor("Count", nPages + 1); - pPageDict->SetReferenceFor("Parent", pDoc, pPages->GetObjNum()); - } else { - std::set stack = {pPages}; - if (InsertDeletePDFPage(pDoc, pPages, iPage, pPageDict, TRUE, &stack) < 0) - return -1; - } - pageList.InsertAt(iPage, pPageDict->GetObjNum()); - return iPage; -} - int CountPages(CPDF_Dictionary* pPages, std::set* visited_pages) { int count = pPages->GetIntegerFor("Count"); @@ -413,6 +337,7 @@ CPDF_Document::CPDF_Document(std::unique_ptr pParser) m_pParser(std::move(pParser)), m_pRootDict(nullptr), m_pInfoDict(nullptr), + m_iLastPageTraversed(-1), m_bLinearized(false), m_iFirstPageNo(0), m_dwFirstPageObjNum(0), @@ -477,40 +402,71 @@ void CPDF_Document::LoadPages() { m_PageList.SetSize(RetrievePageCount()); } -CPDF_Dictionary* CPDF_Document::FindPDFPage(CPDF_Dictionary* pPages, - int iPage, - int nPagesToGo, - int level) { +void CPDF_Document::PopAndPropagate() { + m_pTreeTraversal.pop(); + if (m_pTreeTraversal.empty()) + return; + std::pair* top = &m_pTreeTraversal.top(); + top->second++; + if (top->second == + static_cast(top->first->GetArrayFor("Kids")->GetCount() - 1)) { + PopAndPropagate(); + } +} + +CPDF_Dictionary* CPDF_Document::TraversePDFPages(int iPage, int nPagesToGo) { + std::pair* lastProc = &m_pTreeTraversal.top(); + CPDF_Dictionary* pPages = lastProc->first; CPDF_Array* pKidList = pPages->GetArrayFor("Kids"); - if (!pKidList) - return nPagesToGo == 0 ? pPages : nullptr; + if (!pKidList) { + PopAndPropagate(); + if (nPagesToGo != 1) + return nullptr; + m_PageList.SetAt(iPage, pPages->GetObjNum()); + return pPages; + } - if (level >= FX_MAX_PAGE_LEVEL) + if (m_pTreeTraversal.size() >= FX_MAX_PAGE_LEVEL) { + PopAndPropagate(); return nullptr; + } - for (size_t i = 0; i < pKidList->GetCount(); i++) { + CPDF_Dictionary* page = nullptr; + for (size_t i = lastProc->second + 1; i < pKidList->GetCount(); i++) { CPDF_Dictionary* pKid = pKidList->GetDictAt(i); if (!pKid) { nPagesToGo--; + lastProc->second++; continue; } - if (pKid == pPages) + if (pKid == pPages) { + lastProc->second++; continue; + } if (!pKid->KeyExist("Kids")) { - if (nPagesToGo == 0) - return pKid; - - m_PageList.SetAt(iPage - nPagesToGo, pKid->GetObjNum()); + m_PageList.SetAt(iPage - nPagesToGo + 1, pKid->GetObjNum()); nPagesToGo--; + lastProc->second++; + if (nPagesToGo == 0) { + page = pKid; + break; + } } else { int nPages = pKid->GetIntegerFor("Count"); - if (nPagesToGo < nPages) - return FindPDFPage(pKid, iPage, nPagesToGo, level + 1); - + m_pTreeTraversal.push(std::make_pair(pKid, -1)); + CPDF_Dictionary* pageKid = TraversePDFPages(iPage, nPagesToGo); + if (nPagesToGo <= nPages) { + page = pageKid; + break; + } nPagesToGo -= nPages; } } - return nullptr; + if (!m_pTreeTraversal.empty() && lastProc == &m_pTreeTraversal.top() && + lastProc->second == static_cast(pKidList->GetCount() - 1)) { + PopAndPropagate(); + } + return page; } CPDF_Dictionary* CPDF_Document::GetPagesDict() const { @@ -534,21 +490,20 @@ CPDF_Dictionary* CPDF_Document::GetPage(int iPage) { } int objnum = m_PageList.GetAt(iPage); - if (objnum) { - if (CPDF_Dictionary* pDict = ToDictionary(GetOrParseIndirectObject(objnum))) - return pDict; + if (!objnum) { + CPDF_Dictionary* pPages = GetPagesDict(); + if (!pPages) + return nullptr; + if (m_pTreeTraversal.empty()) + m_pTreeTraversal.push(std::make_pair(pPages, -1)); + CPDF_Dictionary* page = + TraversePDFPages(iPage, iPage - m_iLastPageTraversed); + m_iLastPageTraversed = iPage; + return page; } - - CPDF_Dictionary* pPages = GetPagesDict(); - if (!pPages) - return nullptr; - - CPDF_Dictionary* pPage = FindPDFPage(pPages, iPage, iPage, 0); - if (!pPage) - return nullptr; - - m_PageList.SetAt(iPage, pPage->GetObjNum()); - return pPage; + if (CPDF_Dictionary* pDict = ToDictionary(GetOrParseIndirectObject(objnum))) + return pDict; + return nullptr; } void CPDF_Document::SetPageObjNum(int iPage, uint32_t objNum) { @@ -710,13 +665,94 @@ CPDF_Dictionary* CPDF_Document::CreateNewPage(int iPage) { CPDF_Dictionary* pDict = new CPDF_Dictionary(m_pByteStringPool); pDict->SetNameFor("Type", "Page"); uint32_t dwObjNum = AddIndirectObject(pDict); - if (InsertNewPage(this, iPage, pDict, m_PageList) < 0) { + if (InsertNewPage(iPage, pDict, m_PageList) < 0) { ReleaseIndirectObject(dwObjNum); return nullptr; } return pDict; } +int CPDF_Document::InsertDeletePDFPage(CPDF_Dictionary* pPages, + int nPagesToGo, + CPDF_Dictionary* pPage, + FX_BOOL bInsert, + std::set* pVisited) { + CPDF_Array* pKidList = pPages->GetArrayFor("Kids"); + if (!pKidList) + return -1; + + for (size_t i = 0; i < pKidList->GetCount(); i++) { + CPDF_Dictionary* pKid = pKidList->GetDictAt(i); + if (pKid->GetStringFor("Type") == "Page") { + if (nPagesToGo == 0) { + if (bInsert) { + pKidList->InsertAt(i, new CPDF_Reference(this, pPage->GetObjNum())); + pPage->SetReferenceFor("Parent", this, pPages->GetObjNum()); + } else { + pKidList->RemoveAt(i); + } + pPages->SetIntegerFor( + "Count", pPages->GetIntegerFor("Count") + (bInsert ? 1 : -1)); + // Tree will change, so reset tree transversal variables + m_iLastPageTraversed = -1; + m_pTreeTraversal = std::stack>(); + return 1; + } + nPagesToGo--; + } else { + int nPages = pKid->GetIntegerFor("Count"); + if (nPagesToGo < nPages) { + if (pdfium::ContainsKey(*pVisited, pKid)) + return -1; + + pdfium::ScopedSetInsertion insertion(pVisited, pKid); + if (InsertDeletePDFPage(pKid, nPagesToGo, pPage, bInsert, pVisited) < + 0) { + return -1; + } + pPages->SetIntegerFor( + "Count", pPages->GetIntegerFor("Count") + (bInsert ? 1 : -1)); + return 1; + } + nPagesToGo -= nPages; + } + } + return 0; +} + +int CPDF_Document::InsertNewPage(int iPage, + CPDF_Dictionary* pPageDict, + CFX_ArrayTemplate& pageList) { + CPDF_Dictionary* pRoot = GetRoot(); + CPDF_Dictionary* pPages = pRoot ? pRoot->GetDictFor("Pages") : nullptr; + if (!pPages) + return -1; + + int nPages = GetPageCount(); + if (iPage < 0 || iPage > nPages) + return -1; + + if (iPage == nPages) { + CPDF_Array* pPagesList = pPages->GetArrayFor("Kids"); + if (!pPagesList) { + pPagesList = new CPDF_Array; + pPages->SetFor("Kids", pPagesList); + } + pPagesList->Add(new CPDF_Reference(this, pPageDict->GetObjNum())); + pPages->SetIntegerFor("Count", nPages + 1); + pPageDict->SetReferenceFor("Parent", this, pPages->GetObjNum()); + // Reset tree transversal variables + m_iLastPageTraversed = -1; + m_pTreeTraversal = std::stack>(); + } else { + std::set stack = {pPages}; + if (InsertDeletePDFPage(pPages, iPage, pPageDict, TRUE, &stack) < 0) + return -1; + } + pageList.InsertAt(iPage, pPageDict->GetObjNum()); + return iPage; +} + void CPDF_Document::DeletePage(int iPage) { CPDF_Dictionary* pPages = GetPagesDict(); if (!pPages) @@ -727,7 +763,7 @@ void CPDF_Document::DeletePage(int iPage) { return; std::set stack = {pPages}; - if (InsertDeletePDFPage(this, pPages, iPage, nullptr, FALSE, &stack) < 0) + if (InsertDeletePDFPage(pPages, iPage, nullptr, FALSE, &stack) < 0) return; m_PageList.RemoveAt(iPage); diff --git a/core/fpdfapi/parser/cpdf_document.h b/core/fpdfapi/parser/cpdf_document.h index ea7bd328aa..ef9f663c3b 100644 --- a/core/fpdfapi/parser/cpdf_document.h +++ b/core/fpdfapi/parser/cpdf_document.h @@ -9,6 +9,7 @@ #include #include +#include #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h" #include "core/fpdfapi/parser/cpdf_object.h" @@ -105,10 +106,7 @@ class CPDF_Document : public CPDF_IndirectObjectHolder { protected: // Retrieve page count information by getting count value from the tree nodes int RetrievePageCount() const; - CPDF_Dictionary* FindPDFPage(CPDF_Dictionary* pPages, - int iPage, - int nPagesToGo, - int level); + CPDF_Dictionary* TraversePDFPages(int iPage, int nPagesToGo); int FindPageIndex(CPDF_Dictionary* pNode, uint32_t& skip_count, uint32_t objnum, @@ -124,10 +122,23 @@ class CPDF_Document : public CPDF_IndirectObjectHolder { FX_BOOL bVert, CFX_ByteString basefont, std::function Insert); - + int InsertDeletePDFPage(CPDF_Dictionary* pPages, + int nPagesToGo, + CPDF_Dictionary* pPage, + FX_BOOL bInsert, + std::set* pVisited); + int InsertNewPage(int iPage, + CPDF_Dictionary* pPageDict, + CFX_ArrayTemplate& pageList); + void PopAndPropagate(); std::unique_ptr m_pParser; CPDF_Dictionary* m_pRootDict; CPDF_Dictionary* m_pInfoDict; + // Stack of page nodes to know current position in page tree. Int is the index + // of last processed child. + std::stack> m_pTreeTraversal; + // Index of last page (leaf) processed from page tree. + int m_iLastPageTraversed; bool m_bLinearized; int m_iFirstPageNo; uint32_t m_dwFirstPageObjNum; -- cgit v1.2.3