Added FPDFAnnot_RemoveAnnot()

Added an API for removing annotation and an embedder test for it.

Bug=pdfium:737

Change-Id: I6f01625e8103078b83967a57a5c1a7a26bc0c70a
Reviewed-on: https://pdfium-review.googlesource.com/7039
Commit-Queue: Jane Liu <janeliulwq@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>

3 files changed, 83 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfannot.cpp b/fpdfsdk/fpdfannot.cpp
index 4a288b7df7..3d003d738e 100644
--- a/fpdfsdk/fpdfannot.cpp
+++ b/fpdfsdk/fpdfannot.cpp
@@ -201,6 +201,19 @@ DLLEXPORT void STDCALL FPDFPage_CloseAnnot(FPDF_ANNOTATION annot) {
   delete CPDFAnnotContextFromFPDFAnnotation(annot);
 }
 
+DLLEXPORT FPDF_BOOL STDCALL FPDFPage_RemoveAnnot(FPDF_PAGE page, int index) {
+  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
+  if (!pPage || !pPage->m_pFormDict || index < 0)
+    return false;
+
+  CPDF_Array* pAnnots = pPage->m_pFormDict->GetArrayFor("Annots");
+  if (!pAnnots || static_cast<size_t>(index) >= pAnnots->GetCount())
+    return false;
+
+  pAnnots->RemoveAt(index);
+  return true;
+}
+
 DLLEXPORT FPDF_ANNOTATION_SUBTYPE STDCALL
 FPDFAnnot_GetSubtype(FPDF_ANNOTATION annot) {
   if (!annot)
diff --git a/fpdfsdk/fpdfannot_embeddertest.cpp b/fpdfsdk/fpdfannot_embeddertest.cpp
index 9d9e2d365f..85fe1326bc 100644
--- a/fpdfsdk/fpdfannot_embeddertest.cpp
+++ b/fpdfsdk/fpdfannot_embeddertest.cpp
@@ -392,3 +392,72 @@ TEST_F(FPDFAnnotEmbeddertest, ModifyRectQuadpointsWithAP) {
   FPDFPage_CloseAnnot(annot);
   UnloadPage(page);
 }
+
+TEST_F(FPDFAnnotEmbeddertest, RemoveAnnotation) {
+  // Open a file with 3 annotations on its first page.
+  ASSERT_TRUE(OpenDocument("annotation_ink_multiple.pdf"));
+  FPDF_PAGE page = FPDF_LoadPage(document(), 0);
+  ASSERT_TRUE(page);
+  EXPECT_EQ(3, FPDFPage_GetAnnotCount(page));
+
+  // Check that the annotations have the expected rectangle coordinates.
+  FPDF_ANNOTATION annot = FPDFPage_GetAnnot(page, 0);
+  FS_RECTF rect = FPDFAnnot_GetRect(annot);
+  EXPECT_NEAR(86.1971f, rect.left, 0.001f);
+  FPDFPage_CloseAnnot(annot);
+
+  annot = FPDFPage_GetAnnot(page, 1);
+  rect = FPDFAnnot_GetRect(annot);
+  EXPECT_NEAR(149.8127f, rect.left, 0.001f);
+  FPDFPage_CloseAnnot(annot);
+
+  annot = FPDFPage_GetAnnot(page, 2);
+  rect = FPDFAnnot_GetRect(annot);
+  EXPECT_NEAR(351.8204f, rect.left, 0.001f);
+  FPDFPage_CloseAnnot(annot);
+
+  // Check that nothing happens when attempting to remove an annotation with an
+  // out-of-bound index.
+  EXPECT_FALSE(FPDFPage_RemoveAnnot(page, 4));
+  EXPECT_FALSE(FPDFPage_RemoveAnnot(page, -1));
+  EXPECT_EQ(3, FPDFPage_GetAnnotCount(page));
+
+  // Remove the second annotation.
+  EXPECT_TRUE(FPDFPage_RemoveAnnot(page, 1));
+  EXPECT_EQ(2, FPDFPage_GetAnnotCount(page));
+  EXPECT_FALSE(FPDFPage_GetAnnot(page, 2));
+
+  // Save the document, closing the page and document.
+  EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));
+  FPDF_ClosePage(page);
+
+  // Open the saved document.
+  std::string new_file = GetString();
+  FPDF_FILEACCESS file_access;
+  memset(&file_access, 0, sizeof(file_access));
+  file_access.m_FileLen = new_file.size();
+  file_access.m_GetBlock = GetBlockFromString;
+  file_access.m_Param = &new_file;
+  FPDF_DOCUMENT new_doc = FPDF_LoadCustomDocument(&file_access, nullptr);
+  ASSERT_TRUE(new_doc);
+  FPDF_PAGE new_page = FPDF_LoadPage(new_doc, 0);
+  ASSERT_TRUE(new_page);
+
+  // Check that the saved document has 2 annotations on the first page.
+  EXPECT_EQ(2, FPDFPage_GetAnnotCount(new_page));
+
+  // Check that the remaining 2 annotations are the original 1st and 3rd ones by
+  // verifying their rectangle coordinates.
+  annot = FPDFPage_GetAnnot(new_page, 0);
+  rect = FPDFAnnot_GetRect(annot);
+  EXPECT_NEAR(86.1971f, rect.left, 0.001f);
+  FPDFPage_CloseAnnot(annot);
+
+  annot = FPDFPage_GetAnnot(new_page, 1);
+  rect = FPDFAnnot_GetRect(annot);
+  EXPECT_NEAR(351.8204f, rect.left, 0.001f);
+  FPDFPage_CloseAnnot(annot);
+
+  FPDF_ClosePage(new_page);
+  FPDF_CloseDocument(new_doc);
+}
diff --git a/fpdfsdk/fpdfview_c_api_test.c b/fpdfsdk/fpdfview_c_api_test.c
index 05242c6fe1..f9a3c387c2 100644
--- a/fpdfsdk/fpdfview_c_api_test.c
+++ b/fpdfsdk/fpdfview_c_api_test.c
@@ -40,6 +40,7 @@ int CheckPDFiumCApi() {
     CHK(FPDFPage_GetAnnotCount);
     CHK(FPDFPage_GetAnnot);
     CHK(FPDFPage_CloseAnnot);
+    CHK(FPDFPage_RemoveAnnot);
     CHK(FPDFAnnot_GetSubtype);
     CHK(FPDFAnnot_SetColor);
     CHK(FPDFAnnot_GetColor);