Add functions to collect bookmarks from Pdfium

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 213214f5311a35a1064722d5b26b97cb7d3cb06c..76ed9e0fc7a73c25ea15e4a5ad8337524f2623fc 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -30,6 +30,7 @@
 #include "ppapi/cpp/trusted/browser_font_trusted.h"
 #include "ppapi/cpp/url_response_info.h"
 #include "ppapi/cpp/var.h"
+#include "ppapi/cpp/var_dictionary.h"
 #include "third_party/pdfium/fpdfsdk/include/fpdf_ext.h"
 #include "third_party/pdfium/fpdfsdk/include/fpdf_flatten.h"
 #include "third_party/pdfium/fpdfsdk/include/fpdf_searchex.h"
@@ -527,6 +528,39 @@ void FormatStringForOS(base::string16* text) {
 #endif
 }
 
+// Returns a VarDictionary (representing a bookmark), which in turn contains
+// child VarDictionaries (representing the child bookmarks).
+// If NULL is passed in as the bookmark then we traverse from the "root".
+// Note that the "root" bookmark contains no useful information.
+pp::VarDictionary TraverseBookmarks(FPDF_DOCUMENT doc, FPDF_BOOKMARK bookmark) {
+  pp::VarDictionary dict;
+  base::string16 title;
+  size_t buffer_size = FPDFBookmark_GetTitle(bookmark, NULL, 0);

[raymes, 2015/01/14 00:26:06]

-We should use unsigned long here rather than size_t (the same as the api).
-The problem here is that we are passing the buffer size to WriteInto rather
than the length of the text. We should use

title_length = buffer_size / sizeof(base::string16::value_type)

to compute the title length and then 

if (title_length > 1) 
......WriteInto(... title_length)

[Alexandre Carlton, 2015/01/15 22:53:49]

Done. This resolves the trailing \u0000 characters.

+  if (buffer_size > 0) {
+    FPDFBookmark_GetTitle(bookmark,
+        WriteInto(&title, buffer_size), buffer_size);
+  }

[raymes, 2015/01/13 07:13:26]

See https://codereview.chromium.org/833263003/. We may have to resize the string
to avoid the trailing NULLs

[Alexandre Carlton, 2015/01/15 22:53:49]

Done.

+  dict.Set(pp::Var("title"), pp::Var(base::UTF16ToUTF8(title)));
+
+  FPDF_DEST dest = FPDFBookmark_GetDest(doc, bookmark);
+  // Some bookmarks don't have a page to select.
+  if (dest) {
+    int page_index = FPDFDest_GetPageIndex(doc, dest);
+    dict.Set(pp::Var("page"), pp::Var(page_index));
+  }
+
+  pp::VarArray children;
+  int child_index = 0;
+  for (FPDF_BOOKMARK child_bookmark = FPDFBookmark_GetFirstChild(doc, bookmark);
+      child_bookmark != NULL;
+      child_bookmark = FPDFBookmark_GetNextSibling(doc, child_bookmark)) {
+    children.Set(child_index, TraverseBookmarks(doc, child_bookmark));
+    child_index++;
+  }
+  dict.Set(pp::Var("children"), children);
+  return dict;
+}
+
 }  // namespace
 
 bool InitializeSDK(void* data) {
@@ -2297,6 +2331,13 @@ int PDFiumEngine::GetNumberOfPages() {
   return pages_.size();
 }
 
+
+pp::VarArray PDFiumEngine::GetBookmarks() {
+  pp::VarDictionary dict = TraverseBookmarks(doc_, NULL);
+  // The root bookmark contains no useful information.
+  return pp::VarArray(dict.Get(pp::Var("children")));
+}
+
 int PDFiumEngine::GetNamedDestinationPage(const std::string& destination) {
   // Look for the destination.
   FPDF_DEST dest = FPDF_GetNamedDestByName(doc_, destination.c_str());