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-rw-r--r--core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp11
-rw-r--r--core/fpdfapi/edit/cpdf_pagecontentmanager.cpp60
-rw-r--r--core/fpdfapi/edit/cpdf_pagecontentmanager.h11
3 files changed, 78 insertions, 4 deletions
diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
index 80b121a572..da6c74e2c7 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
@@ -161,11 +161,14 @@ void CPDF_PageContentGenerator::UpdateContentStreams(
page_content_manager.GetStreamByIndex(stream_index);
ASSERT(old_stream);
- // TODO(pdfium:1051): Remove streams that are now empty. If buf is empty,
- // remove this instead of setting the data.
-
- old_stream->SetData(buf);
+ // If buf is now empty, remove the stream instead of setting the data.
+ if (buf->tellp() <= 0)
+ page_content_manager.ScheduleRemoveStreamByIndex(stream_index);
+ else
+ old_stream->SetData(buf);
}
+
+ page_content_manager.ExecuteScheduledRemovals();
}
ByteString CPDF_PageContentGenerator::RealizeResource(
diff --git a/core/fpdfapi/edit/cpdf_pagecontentmanager.cpp b/core/fpdfapi/edit/cpdf_pagecontentmanager.cpp
index e9ade27bf8..46033bc0d1 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentmanager.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentmanager.cpp
@@ -4,6 +4,11 @@
#include "core/fpdfapi/edit/cpdf_pagecontentmanager.h"
+#include <map>
+#include <numeric>
+#include <vector>
+
+#include "core/fpdfapi/page/cpdf_pageobject.h"
#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/cpdf_document.h"
@@ -85,3 +90,58 @@ size_t CPDF_PageContentManager::AddStream(std::ostringstream* buf) {
contents_stream_ = new_stream;
return 0;
}
+
+void CPDF_PageContentManager::ScheduleRemoveStreamByIndex(size_t stream_index) {
+ streams_to_remove_.insert(stream_index);
+}
+
+void CPDF_PageContentManager::ExecuteScheduledRemovals() {
+ // This method assumes there are no dirty streams in the
+ // CPDF_PageObjectHolder. If there were any, their indexes would need to be
+ // updated.
+ // Since this is only called by CPDF_PageContentGenerator::GenerateContent(),
+ // which cleans up the dirty streams first, this should always be true.
+ ASSERT(obj_holder_->GetDirtyStreams()->empty());
+
+ if (contents_stream_) {
+ // Only stream that can be removed is 0.
+ if (streams_to_remove_.find(0) != streams_to_remove_.end()) {
+ CPDF_Dictionary* page_dict = obj_holder_->GetDict();
+ page_dict->RemoveFor("Contents");
+ contents_stream_ = nullptr;
+ }
+ } else if (contents_array_) {
+ // Initialize a vector with the old stream indexes. This will be used to
+ // build a map from the old to the new indexes.
+ std::vector<size_t> streams_left(contents_array_->GetCount());
+ std::iota(streams_left.begin(), streams_left.end(), 0);
+
+ // In reverse order so as to not change the indexes in the middle of the
+ // loop, remove the streams.
+ for (auto it = streams_to_remove_.rbegin(); it != streams_to_remove_.rend();
+ ++it) {
+ size_t stream_index = *it;
+ contents_array_->RemoveAt(stream_index);
+ streams_left.erase(streams_left.begin() + stream_index);
+ }
+
+ // Create a mapping from the old to the new stream indexes, shifted due to
+ // the deletion of the |streams_to_remove_|.
+ std::map<int32_t, size_t> stream_index_mapping;
+ for (size_t i = 0; i < streams_left.size(); ++i)
+ stream_index_mapping[streams_left[i]] = i;
+
+ // Update the page objects' content stream indexes.
+ for (const auto& obj : *obj_holder_->GetPageObjectList()) {
+ int32_t old_stream_index = obj->GetContentStream();
+ size_t new_stream_index = stream_index_mapping[old_stream_index];
+ obj->SetContentStream(new_stream_index);
+ }
+
+ // Even if there is a single content stream now, keep the array with a
+ // single element. It's valid, a second stream might be added soon, and the
+ // complexity of removing it is not worth it.
+ }
+
+ streams_to_remove_.clear();
+}
diff --git a/core/fpdfapi/edit/cpdf_pagecontentmanager.h b/core/fpdfapi/edit/cpdf_pagecontentmanager.h
index 384405b188..bad8c7a38c 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentmanager.h
+++ b/core/fpdfapi/edit/cpdf_pagecontentmanager.h
@@ -5,6 +5,7 @@
#ifndef CORE_FPDFAPI_EDIT_CPDF_PAGECONTENTMANAGER_H_
#define CORE_FPDFAPI_EDIT_CPDF_PAGECONTENTMANAGER_H_
+#include <set>
#include <sstream>
#include "core/fxcrt/unowned_ptr.h"
@@ -28,11 +29,21 @@ class CPDF_PageContentManager {
// if Contents is not an array, but only a single stream.
size_t AddStream(std::ostringstream* buf);
+ // Schedule the removal of the Content stream at a given index. It will be
+ // removed when ExecuteScheduledRemovals() is called.
+ void ScheduleRemoveStreamByIndex(size_t stream_index);
+
+ // Remove all Content streams for which ScheduleRemoveStreamByIndex() was
+ // called. Update the content stream of all page objects with the shifted
+ // indexes.
+ void ExecuteScheduledRemovals();
+
private:
UnownedPtr<CPDF_PageObjectHolder> const obj_holder_;
UnownedPtr<CPDF_Document> const doc_;
UnownedPtr<CPDF_Array> contents_array_;
UnownedPtr<CPDF_Stream> contents_stream_;
+ std::set<size_t> streams_to_remove_;
};
#endif // CORE_FPDFAPI_EDIT_CPDF_PAGECONTENTMANAGER_H_