Add FPDFText_GetFontName() API

This follows the same pattern as DefaultGetFaceName(), so the client has
to call this function twice, but allocation of the string buffer happens
outside pdfium.

Change-Id: I06b7dcd00aca9b9b94799dad3f139617d7f5451e
Reviewed-on: https://pdfium-review.googlesource.com/38870
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

5 files changed, 69 insertions, 0 deletions

diff --git a/fpdfsdk/fpdf_edit_embeddertest.cpp b/fpdfsdk/fpdf_edit_embeddertest.cpp
index c9805f50c7..3c2b05ed8a 100644
--- a/fpdfsdk/fpdf_edit_embeddertest.cpp
+++ b/fpdfsdk/fpdf_edit_embeddertest.cpp
@@ -1764,6 +1764,34 @@ TEST_F(FPDFEditEmbeddertest, TestGetTextRenderMode) {
   UnloadPage(page);
 }
 
+TEST_F(FPDFEditEmbeddertest, TestGetTextFontName) {
+  EXPECT_TRUE(OpenDocument("text_font.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+  ASSERT_EQ(1, FPDFPage_CountObjects(page));
+
+  // FPDFTextObj_GetFontName() positive testing.
+  FPDF_PAGEOBJECT text = FPDFPage_GetObject(page, 0);
+  unsigned long size = FPDFTextObj_GetFontName(text, nullptr, 0);
+  const char kExpectedFontName[] = "Liberation Serif";
+  ASSERT_EQ(sizeof(kExpectedFontName), size);
+  std::vector<char> font_name(size);
+  ASSERT_EQ(size, FPDFTextObj_GetFontName(text, font_name.data(), size));
+  ASSERT_STREQ(kExpectedFontName, font_name.data());
+
+  // FPDFTextObj_GetFontName() negative testing.
+  ASSERT_EQ(0U, FPDFTextObj_GetFontName(nullptr, nullptr, 0));
+
+  font_name.resize(2);
+  font_name[0] = 'x';
+  font_name[1] = '\0';
+  size = FPDFTextObj_GetFontName(text, font_name.data(), font_name.size());
+  ASSERT_EQ(sizeof(kExpectedFontName), size);
+  ASSERT_EQ(std::string("x"), std::string(font_name.data()));
+
+  UnloadPage(page);
+}
+
 TEST_F(FPDFEditEmbeddertest, TestFormGetObjects) {
   EXPECT_TRUE(OpenDocument("form_object.pdf"));
   FPDF_PAGE page = LoadPage(0);
diff --git a/fpdfsdk/fpdf_edittext.cpp b/fpdfsdk/fpdf_edittext.cpp
index c552d615e4..6aa44b3b20 100644
--- a/fpdfsdk/fpdf_edittext.cpp
+++ b/fpdfsdk/fpdf_edittext.cpp
@@ -542,6 +542,28 @@ FPDF_EXPORT double FPDF_CALLCONV FPDFTextObj_GetFontSize(FPDF_PAGEOBJECT text) {
   return pTextObj ? pTextObj->GetFontSize() : 0;
 }
 
+FPDF_EXPORT unsigned long FPDF_CALLCONV
+FPDFTextObj_GetFontName(FPDF_PAGEOBJECT text,
+                        void* buffer,
+                        unsigned long length) {
+  CPDF_TextObject* pTextObj = CPDFTextObjectFromFPDFPageObject(text);
+  if (!pTextObj)
+    return 0;
+
+  CPDF_Font* pPdfFont = pTextObj->GetFont();
+  if (!pPdfFont)
+    return 0;
+
+  CFX_Font* pFont = pPdfFont->GetFont();
+  ASSERT(pFont);
+
+  ByteString name = pFont->GetFamilyName();
+  unsigned long dwStringLen = name.GetLength() + 1;
+  if (buffer && length >= dwStringLen)
+    memcpy(buffer, name.c_str(), dwStringLen);
+  return dwStringLen;
+}
+
 FPDF_EXPORT void FPDF_CALLCONV FPDFFont_Close(FPDF_FONT font) {
   CPDF_Font* pFont = CPDFFontFromFPDFFont(font);
   if (!pFont)
diff --git a/fpdfsdk/fpdf_view_c_api_test.c b/fpdfsdk/fpdf_view_c_api_test.c
index 4faf5bbf0f..91d24fd233 100644
--- a/fpdfsdk/fpdf_view_c_api_test.c
+++ b/fpdfsdk/fpdf_view_c_api_test.c
@@ -204,6 +204,7 @@ int CheckPDFiumCApi() {
     CHK(FPDFPath_SetMatrix);
     CHK(FPDFPath_SetStrokeColor);
     CHK(FPDFPath_SetStrokeWidth);
+    CHK(FPDFTextObj_GetFontName);
     CHK(FPDFTextObj_GetFontSize);
     CHK(FPDFText_GetMatrix);
     CHK(FPDFText_GetTextRenderMode);
diff --git a/public/fpdf_edit.h b/public/fpdf_edit.h
index b97a7adbd9..4d5aa9c48a 100644
--- a/public/fpdf_edit.h
+++ b/public/fpdf_edit.h
@@ -1257,6 +1257,24 @@ FPDFPageObj_CreateTextObj(FPDF_DOCUMENT document,
 FPDF_EXPORT int FPDF_CALLCONV FPDFText_GetTextRenderMode(FPDF_PAGEOBJECT text);
 
 // Experimental API.
+// Get the font name of a text object.
+//
+// text             - the handle to the text object.
+// buffer           - the address of a buffer that receives the font name.
+// length           - the size, in bytes, of |buffer|.
+//
+// Returns the number of bytes in the font name (including the trailing NUL
+// character) on success, 0 on error.
+//
+// Regardless of the platform, the |buffer| is always in UTF-8 encoding.
+// If |length| is less than the returned length, or |buffer| is NULL, |buffer|
+// will not be modified.
+FPDF_EXPORT unsigned long FPDF_CALLCONV
+FPDFTextObj_GetFontName(FPDF_PAGEOBJECT text,
+                        void* buffer,
+                        unsigned long length);
+
+// Experimental API.
 // Get number of page objects inside |form_object|.
 //
 //   form_object - handle to a form object.
diff --git a/testing/resources/text_font.pdf b/testing/resources/text_font.pdf
new file mode 100644
index 0000000000..78f3bcc784
--- /dev/null
+++ b/testing/resources/text_font.pdf