Add a build target and a proper export header for shared library builds.

This CL adds support for Chromium's component build feature to pdfium.

The export header stub in fpdfview.h is expanded to match Chromium's
export mechanisms and patterns (fixes pdfium:825).

A component/shared library build can be triggered by adding

is_component_build = true

as a gn argument. Please note that setting this will also affect some
of pdfiums dependencies like v8, which will be build as components
too.

Additionally, this CL provides a "pdf_source_set" template which
dynamically enables the use of "source_set" when building a complete
static library or a shared library to reduce build time.

When testing this it is recommended to only build the pdfium target as
most of pdfiums test rely on non-public functions which aren't exported
by the shared library.

Bug: pdfium:825,pdfium:826
Change-Id: Icedc538ec535e11d1e53c4d5fabc8c064b275752
Reviewed-on: https://pdfium-review.googlesource.com/8970
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

1 files changed, 19 insertions, 17 deletions

diff --git a/fpdfsdk/fpdfedittext.cpp b/fpdfsdk/fpdfedittext.cpp
index f498917a19..47facb4345 100644
--- a/fpdfsdk/fpdfedittext.cpp
+++ b/fpdfsdk/fpdfedittext.cpp
@@ -396,9 +396,10 @@ void* LoadCompositeFont(CPDF_Document* pDoc,
 
 }  // namespace
 
-DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPageObj_NewTextObj(FPDF_DOCUMENT document,
-                                                         FPDF_BYTESTRING font,
-                                                         float font_size) {
+FPDF_EXPORT FPDF_PAGEOBJECT FPDF_CALLCONV
+FPDFPageObj_NewTextObj(FPDF_DOCUMENT document,
+                       FPDF_BYTESTRING font,
+                       float font_size) {
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return nullptr;
@@ -414,8 +415,8 @@ DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPageObj_NewTextObj(FPDF_DOCUMENT document,
   return pTextObj.release();  // Caller takes ownership.
 }
 
-DLLEXPORT FPDF_BOOL STDCALL FPDFText_SetText(FPDF_PAGEOBJECT text_object,
-                                             FPDF_WIDESTRING text) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
+FPDFText_SetText(FPDF_PAGEOBJECT text_object, FPDF_WIDESTRING text) {
   auto* pTextObj = static_cast<CPDF_TextObject*>(text_object);
   if (!pTextObj)
     return false;
@@ -431,11 +432,11 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFText_SetText(FPDF_PAGEOBJECT text_object,
   return true;
 }
 
-DLLEXPORT FPDF_FONT STDCALL FPDFText_LoadFont(FPDF_DOCUMENT document,
-                                              const uint8_t* data,
-                                              uint32_t size,
-                                              int font_type,
-                                              FPDF_BOOL cid) {
+FPDF_EXPORT FPDF_FONT FPDF_CALLCONV FPDFText_LoadFont(FPDF_DOCUMENT document,
+                                                      const uint8_t* data,
+                                                      uint32_t size,
+                                                      int font_type,
+                                                      FPDF_BOOL cid) {
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc || !data || size == 0 ||
       (font_type != FPDF_FONT_TYPE1 && font_type != FPDF_FONT_TRUETYPE)) {
@@ -454,15 +455,16 @@ DLLEXPORT FPDF_FONT STDCALL FPDFText_LoadFont(FPDF_DOCUMENT document,
              : LoadSimpleFont(pDoc, std::move(pFont), data, size, font_type);
 }
 
-DLLEXPORT FPDF_BOOL STDCALL FPDFText_SetFillColor(FPDF_PAGEOBJECT text_object,
-                                                  unsigned int R,
-                                                  unsigned int G,
-                                                  unsigned int B,
-                                                  unsigned int A) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
+FPDFText_SetFillColor(FPDF_PAGEOBJECT text_object,
+                      unsigned int R,
+                      unsigned int G,
+                      unsigned int B,
+                      unsigned int A) {
   return FPDFPageObj_SetFillColor(text_object, R, G, B, A);
 }
 
-DLLEXPORT void STDCALL FPDFFont_Close(FPDF_FONT font) {
+FPDF_EXPORT void FPDF_CALLCONV FPDFFont_Close(FPDF_FONT font) {
   CPDF_Font* pFont = static_cast<CPDF_Font*>(font);
   if (!pFont)
     return;
@@ -476,7 +478,7 @@ DLLEXPORT void STDCALL FPDFFont_Close(FPDF_FONT font) {
     pPageData->ReleaseFont(pFont->GetFontDict());
 }
 
-DLLEXPORT FPDF_PAGEOBJECT STDCALL
+FPDF_EXPORT FPDF_PAGEOBJECT FPDF_CALLCONV
 FPDFPageObj_CreateTextObj(FPDF_DOCUMENT document,
                           FPDF_FONT font,
                           float font_size) {