Export internal symbols for shared library builds (#1283)

These symbols are internal to FTXUI (located in src/), but they must be
exported when building as shared libraries because of internal
dependencies between the screen, dom, and component libraries.

- SCREEN symbols in string_internal.hpp are used by COMPONENT.
- DOM symbols in node_decorator.hpp are used by COMPONENT.

Other internal symbols used only by tests were reverted to keep the
shared library API minimal. Note that internal unit tests may fail to
link in shared library mode as a result.

Author: ArthurSonzogni

src/ftxui/dom/node_decorator.hpp

@@ -8,12 +8,14 @@
 
 #include "ftxui/dom/elements.hpp"  // for Element, unpack
 #include "ftxui/dom/node.hpp"      // for Node
+#include "ftxui/util/export.hpp"   // for FTXUI_EXPORT
 
 namespace ftxui {
 struct Box;
 
 // Helper class.
-class NodeDecorator : public Node {
+// Internal class exported for the 'component' library.
+class FTXUI_EXPORT(DOM) NodeDecorator : public Node {
  public:
   explicit NodeDecorator(Element child) : Node(unpack(std::move(child))) {}
   void ComputeRequirement() override;

src/ftxui/screen/string_internal.hpp

@@ -8,30 +8,36 @@
 #include <string>
 #include <vector>
 
+#include "ftxui/util/export.hpp"
+
 namespace ftxui {
 
+// Internal functions exported for the 'component' library.
+FTXUI_EXPORT(SCREEN)
 bool EatCodePoint(std::string_view input,
                   size_t start,
                   size_t* end,
                   uint32_t* ucs);
+FTXUI_EXPORT(SCREEN)
 bool EatCodePoint(std::wstring_view input,
                   size_t start,
                   size_t* end,
                   uint32_t* ucs);
 
-bool IsCombining(uint32_t ucs);
-bool IsFullWidth(uint32_t ucs);
-bool IsControl(uint32_t ucs);
+FTXUI_EXPORT(SCREEN) bool IsCombining(uint32_t ucs);
+FTXUI_EXPORT(SCREEN) bool IsFullWidth(uint32_t ucs);
+FTXUI_EXPORT(SCREEN) bool IsControl(uint32_t ucs);
 
-size_t GlyphPrevious(std::string_view input, size_t start);
-size_t GlyphNext(std::string_view input, size_t start);
+FTXUI_EXPORT(SCREEN) size_t GlyphPrevious(std::string_view input, size_t start);
+FTXUI_EXPORT(SCREEN) size_t GlyphNext(std::string_view input, size_t start);
 
 // Return the index in the |input| string of the glyph at |glyph_offset|,
 // starting at |start|
+FTXUI_EXPORT(SCREEN)
 size_t GlyphIterate(std::string_view input, int glyph_offset, size_t start = 0);
 
 // Returns the number of glyphs in |input|.
-int GlyphCount(std::string_view input);
+FTXUI_EXPORT(SCREEN) int GlyphCount(std::string_view input);
 
 // Properties from:
 // https://www.unicode.org/Public/UCD/latest/ucd/auxiliary/WordBreakProperty.txt
@@ -55,9 +61,12 @@ enum class WordBreakProperty : int8_t {
   WSegSpace,
   ZWJ,
 };
+FTXUI_EXPORT(SCREEN)
 WordBreakProperty CodepointToWordBreakProperty(uint32_t codepoint);
+FTXUI_EXPORT(SCREEN)
 std::vector<WordBreakProperty> Utf8ToWordBreakProperty(std::string_view input);
 
+FTXUI_EXPORT(SCREEN)
 bool IsWordBreakingCharacter(std::string_view input, size_t glyph_index);
 }  // namespace ftxui