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authornpm <npm@chromium.org>2016-10-18 10:38:20 -0700
committerCommit bot <commit-bot@chromium.org>2016-10-18 10:38:20 -0700
commit7c29e27dae139a205755c1a29b7f3ac8b36ec0da (patch)
tree9cc6b44a5c498e7b4c0ddf3dddb4a30654852ea5 /core/fpdfapi/parser/cpdf_document.cpp
parentf3c5fc09f0818ec378890ade42bef40eebd3f0a9 (diff)
downloadpdfium-7c29e27dae139a205755c1a29b7f3ac8b36ec0da.tar.xz
Traverse PDF page tree only once in CPDF_Documentchromium/2895
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: 1 minute 40 seconds After this CL: 5 seconds BUG=chromium:638513 Review-Url: https://codereview.chromium.org/2414423002
Diffstat (limited to 'core/fpdfapi/parser/cpdf_document.cpp')
-rw-r--r--core/fpdfapi/parser/cpdf_document.cpp245
1 files changed, 135 insertions, 110 deletions
diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp
index c5f64a790c..ba20ff6223 100644
--- a/core/fpdfapi/parser/cpdf_document.cpp
+++ b/core/fpdfapi/parser/cpdf_document.cpp
@@ -8,6 +8,7 @@
#include <memory>
#include <set>
+#include <utility>
#include <vector>
#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<CPDF_Dictionary*>* 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<CPDF_Dictionary*> 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<uint32_t>& 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<CPDF_Dictionary*> 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<CPDF_Dictionary*>* visited_pages) {
int count = pPages->GetIntegerFor("Count");
@@ -413,6 +337,7 @@ CPDF_Document::CPDF_Document(std::unique_ptr<CPDF_Parser> 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 +402,63 @@ void CPDF_Document::LoadPages() {
m_PageList.SetSize(RetrievePageCount());
}
-CPDF_Dictionary* CPDF_Document::FindPDFPage(CPDF_Dictionary* pPages,
- int iPage,
- int nPagesToGo,
- int level) {
+CPDF_Dictionary* CPDF_Document::TraversePDFPages(int iPage, int nPagesToGo) {
+ std::pair<CPDF_Dictionary*, int>* lastProc = &m_pTreeTraversal.top();
+ CPDF_Dictionary* pPages = lastProc->first;
CPDF_Array* pKidList = pPages->GetArrayFor("Kids");
- if (!pKidList)
- return nPagesToGo == 0 ? pPages : nullptr;
+ if (!pKidList) {
+ m_pTreeTraversal.pop();
+ 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) {
+ m_pTreeTraversal.pop();
return nullptr;
+ }
- for (size_t i = 0; i < pKidList->GetCount(); i++) {
+ bool shouldFinish = pPages->GetIntegerFor("Count") <= nPagesToGo;
+ 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 the stack top is current element, kid was completely processed.
+ if (lastProc == &m_pTreeTraversal.top())
+ lastProc->second++;
+ if (nPagesToGo <= nPages) {
+ page = pageKid;
+ break;
+ }
nPagesToGo -= nPages;
}
}
- return nullptr;
+ if (shouldFinish ||
+ lastProc->second == static_cast<int>(pKidList->GetCount() - 1)) {
+ m_pTreeTraversal.pop();
+ }
+ return page;
}
CPDF_Dictionary* CPDF_Document::GetPagesDict() const {
@@ -534,21 +482,20 @@ 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 || m_iLastPageTraversed < iPage) {
+ CPDF_Dictionary* pPages = GetPagesDict();
+ if (!pPages)
+ return nullptr;
+ if (m_pTreeTraversal.empty())
+ m_pTreeTraversal.push(std::make_pair(pPages, -1));
+ CPDF_Dictionary* page = TraversePDFPages(m_iLastPageTraversed + 1,
+ 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 +657,91 @@ 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<CPDF_Dictionary*>* 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<std::pair<CPDF_Dictionary*, int>>();
+ return 1;
+ }
+ nPagesToGo--;
+ } else {
+ int nPages = pKid->GetIntegerFor("Count");
+ if (nPagesToGo < nPages) {
+ if (pdfium::ContainsKey(*pVisited, pKid))
+ return -1;
+
+ pdfium::ScopedSetInsertion<CPDF_Dictionary*> 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<uint32_t>& 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());
+ } else {
+ std::set<CPDF_Dictionary*> 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 +752,7 @@ void CPDF_Document::DeletePage(int iPage) {
return;
std::set<CPDF_Dictionary*> stack = {pPages};
- if (InsertDeletePDFPage(this, pPages, iPage, nullptr, FALSE, &stack) < 0)
+ if (InsertDeletePDFPage(pPages, iPage, nullptr, FALSE, &stack) < 0)
return;
m_PageList.RemoveAt(iPage);