Add tests for GetNamedDests() API.

Follow-on work from patch at https://codereview.chromium.org/845643008. This
incorporates that patch, plus adds tests for it and similar conditions.  A few
changes are introduced to correct expected behaviour.

This also incoprorates Deepak's fix in https://codereview.chromium.org/845643008/

This incorporates a formerly unlanded tool to generate small valid PDF
files from template input, which is needed to cover all the error cases
here. See https://codereview.chromium.org/791993006/

BUG=450133
R=bo_xu@foxitsoftware.com

Review URL: https://codereview.chromium.org/837723009

2 files changed, 104 insertions, 1 deletions

diff --git a/fpdfsdk/src/fpdfview.cpp b/fpdfsdk/src/fpdfview.cpp
index 3f6bdd94b3..fba5d65bce 100644
--- a/fpdfsdk/src/fpdfview.cpp
+++ b/fpdfsdk/src/fpdfview.cpp
@@ -848,8 +848,10 @@ DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDest(FPDF_DOCUMENT document, int index,
         pDestObj = nameTree.LookupValue(index, bsName);
     }
     if (!pDestObj) return NULL;
-    if (pDestObj->GetType() == PDFOBJ_DICTIONARY)
+    if (pDestObj->GetType() == PDFOBJ_DICTIONARY) {
         pDestObj = ((CPDF_Dictionary*)pDestObj)->GetArray(FX_BSTRC("D"));
+        if (!pDestObj) return NULL;
+    }
     if (pDestObj->GetType() != PDFOBJ_ARRAY) return NULL;
     CFX_WideString wsName = PDF_DecodeText(bsName);
     CFX_ByteString utf16Name = wsName.UTF16LE_Encode();
@@ -858,6 +860,7 @@ DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDest(FPDF_DOCUMENT document, int index,
         buflen = len;
     } else if (buflen >= len) {
         memcpy(buffer, utf16Name.c_str(), len);
+        buflen = len;
     } else {
         buflen = -1;
     }
diff --git a/fpdfsdk/src/fpdfview_embeddertest.cpp b/fpdfsdk/src/fpdfview_embeddertest.cpp
index 94a51094a8..55c159a42c 100644
--- a/fpdfsdk/src/fpdfview_embeddertest.cpp
+++ b/fpdfsdk/src/fpdfview_embeddertest.cpp
@@ -2,7 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <limits>
+#include <string>
+
 #include "../../testing/embedder_test.h"
+#include "../../fpdfsdk/include/fpdfview.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class FPDFViewEmbeddertest : public EmbedderTest {
@@ -40,3 +44,99 @@ TEST_F(FPDFViewEmbeddertest, ViewerRef) {
   EXPECT_EQ(DuplexUndefined, FPDF_VIEWERREF_GetDuplex(document()));
 }
 
+TEST_F(FPDFViewEmbeddertest, NamedDests) {
+  EXPECT_TRUE(OpenDocument("testing/resources/named_dests.pdf"));
+  long buffer_size;
+  char fixed_buffer[512];
+  FPDF_DEST dest;
+
+  // Query the size of the first item.
+  buffer_size = 2000000; // Absurdly large, check not used for this case.
+  dest = FPDF_GetNamedDest(document(), 0, nullptr, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(12u, buffer_size);
+
+  // Try to retrieve the first item with too small a buffer.
+  buffer_size = 10;
+  dest = FPDF_GetNamedDest(document(), 0, fixed_buffer, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(-1, buffer_size);
+
+  // Try to retrieve the first item with correctly sized buffer. Item is
+  // taken from Dests NameTree in named_dests.pdf.
+  buffer_size = 12;
+  dest = FPDF_GetNamedDest(document(), 0, fixed_buffer, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(12u, buffer_size);
+  EXPECT_EQ(std::string("F\0i\0r\0s\0t\0\0\0", 12),
+            std::string(fixed_buffer, buffer_size));
+
+  // Try to retrieve the second item with ample buffer. Item is taken
+  // from Dests NameTree but has a sub-dictionary in named_dests.pdf.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 1, fixed_buffer, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(10u, buffer_size);
+  EXPECT_EQ(std::string("N\0e\0x\0t\0\0\0", 10),
+            std::string(fixed_buffer, buffer_size));
+
+  // Try to retrieve third item with ample buffer. Item is taken
+  // from Dests NameTree but has a bad sub-dictionary in named_dests.pdf.
+  // in named_dests.pdf).
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 2, fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+
+  // Try to retrieve the forth item with ample buffer. Item is taken
+  // from Dests NameTree but has a vale of the wrong type in named_dests.pdf.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 3, fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+
+  // Try to retrieve fifth item with ample buffer. Item taken from the
+  // old-style Dests dictionary object in named_dests.pdf.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 4, fixed_buffer, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(30u, buffer_size);
+  EXPECT_EQ(
+      std::string("F\0i\0r\0s\0t\0A\0l\0t\0e\0r\0n\0a\0t\0e\0\0\0", 30),
+      std::string(fixed_buffer, buffer_size));
+
+  // Try to retrieve sixth item with ample buffer. Item istaken from the
+  // old-style Dests dictionary object but has a sub-dictionary in
+  // named_dests.pdf.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 5, fixed_buffer, buffer_size);
+  EXPECT_NE(nullptr, dest);
+  EXPECT_EQ(28u, buffer_size);
+  EXPECT_EQ(
+      std::string("L\0a\0s\0t\0A\0l\0t\0e\0r\0n\0a\0t\0e\0\0\0", 28),
+      std::string(fixed_buffer, buffer_size));
+
+  // Try to retrieve non-existent item with ample buffer.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), 6, fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+
+  // Try to underflow/overflow the integer index.
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), std::numeric_limits<int>::max(),
+                           fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), std::numeric_limits<int>::min(),
+                           fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+
+  buffer_size = sizeof(fixed_buffer);
+  dest = FPDF_GetNamedDest(document(), -1, fixed_buffer, buffer_size);
+  EXPECT_EQ(nullptr, dest);
+  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+}