Use Unicode-aware fopen and remove on Windows.

After this commit, SolveSpace can robustly handle non-ASCII filenames
on every OS. Additionally, on Windows, filenames longer than 260
characeters can be used, and files on network shares can be opened
directly, without mounting them as a network drive.

src/export.cpp

@@ -421,7 +421,7 @@ VectorFileWriter *VectorFileWriter::ForFile(const std::string &filename) {
         return NULL;
     }
 
-    FILE *f = fopen(filename.c_str(), "wb");
+    FILE *f = ssfopen(filename, "wb");
     if(!f) {
         Error("Couldn't write to '%s'", filename.c_str());
         return NULL;
@@ -565,7 +565,7 @@ void SolveSpaceUI::ExportMeshTo(const std::string &filename) {
         return;
     }
 
-    FILE *f = fopen(filename.c_str(), "wb");
+    FILE *f = ssfopen(filename, "wb");
     if(!f) {
         Error("Couldn't write to '%s'", filename.c_str());
         return;
@@ -996,7 +996,7 @@ void SolveSpaceUI::ExportAsPngTo(const std::string &filename) {
     SS.GW.Paint();
     SS.showToolbar = prevShowToolbar;
 
-    FILE *f = fopen(filename.c_str(), "wb");
+    FILE *f = ssfopen(filename, "wb");
     if(!f) goto err;
 
     png_struct *png_ptr; png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,

src/exportstep.cpp

@@ -305,7 +305,7 @@ void StepFileWriter::ExportSurfacesTo(const std::string &filename) {
         return;
     }
 
-    f = fopen(filename.c_str(), "wb");
+    f = ssfopen(filename, "wb");
     if(!f) {
         Error("Couldn't write to '%s'", filename.c_str());
         return;

src/file.cpp

@@ -258,7 +258,7 @@ bool SolveSpaceUI::SaveToFile(const std::string &filename) {
     SS.ReloadAllImported();
     SS.GenerateAll(0, INT_MAX);
 
-    fh = fopen(filename.c_str(), "wb");
+    fh = ssfopen(filename, "wb");
     if(!fh) {
         Error("Couldn't write to file '%s'", filename.c_str());
         return false;
@@ -424,7 +424,7 @@ bool SolveSpaceUI::LoadFromFile(const std::string &filename) {
     allConsistent = false;
     fileLoadError = false;
 
-    fh = fopen(filename.c_str(), "rb");
+    fh = ssfopen(filename, "rb");
     if(!fh) {
         Error("Couldn't read from file '%s'", filename.c_str());
         return false;
@@ -509,7 +509,7 @@ bool SolveSpaceUI::LoadEntitiesFromFile(const std::string &filename, EntityList
     SSurface srf = {};
     SCurve crv = {};
 
-    fh = fopen(filename.c_str(), "rb");
+    fh = ssfopen(filename, "rb");
     if(!fh) return false;
 
     le->Clear();
@@ -787,7 +787,7 @@ void SolveSpaceUI::ReloadAllImported(void)
         g->impMesh.Clear();
         g->impShell.Clear();
 
-        FILE *test = fopen(g->impFile.c_str(), "rb");
+        FILE *test = ssfopen(g->impFile, "rb");
         if(test) {
             fclose(test); // okay, exists
         } else {
@@ -796,7 +796,7 @@ void SolveSpaceUI::ReloadAllImported(void)
             if(!SS.saveFile.empty()) {
                 std::string rel = PathSepUNIXToPlatform(g->impFileRel);
                 std::string fromRel = MakePathAbsolute(SS.saveFile, rel);
-                test = fopen(fromRel.c_str(), "rb");
+                test = ssfopen(fromRel, "rb");
                 if(test) {
                     fclose(test);
                     // It worked, this is our new absolute path

src/solvespace.cpp

@@ -105,7 +105,7 @@ void SolveSpaceUI::Init() {
 bool SolveSpaceUI::LoadAutosaveFor(const std::string &filename) {
     std::string autosaveFile = filename + AUTOSAVE_SUFFIX;
 
-    FILE *f = fopen(autosaveFile.c_str(), "r");
+    FILE *f = ssfopen(autosaveFile, "rb");
     if(!f)
         return false;
     fclose(f);
@@ -387,7 +387,7 @@ bool SolveSpaceUI::Autosave()
 void SolveSpaceUI::RemoveAutosave()
 {
     std::string autosaveFile = saveFile + AUTOSAVE_SUFFIX;
-    remove(autosaveFile.c_str());
+    ssremove(autosaveFile.c_str());
 }
 
 bool SolveSpaceUI::OkayToStartNewFile(void) {
@@ -727,7 +727,7 @@ void SolveSpaceUI::MenuAnalyze(int id) {
         case GraphicsWindow::MNU_STOP_TRACING: {
             std::string exportFile;
             if(GetSaveFile(exportFile, CSV_EXT, CSV_PATTERN)) {
-                FILE *f = fopen(exportFile.c_str(), "wb");
+                FILE *f = ssfopen(exportFile, "wb");
                 if(f) {
                     int i;
                     SContour *sc = &(SS.traced.path);

src/solvespace.h

@@ -131,6 +131,9 @@ class RgbaColor;
 #define PATH_SEP "/"
 #endif
 
+FILE *ssfopen(const std::string &filename, const char *mode);
+void ssremove(const std::string &filename);
+
 #define MAX_RECENT 8
 #define RECENT_OPEN     (0xf000)
 #define RECENT_IMPORT   (0xf100)

src/style.cpp

@@ -376,7 +376,7 @@ void TextWindow::ScreenBackgroundImage(int link, uint32_t v) {
 
         std::string importFile;
         if(!GetOpenFile(importFile, PNG_EXT, PNG_PATTERN)) goto err;
-        f = fopen(importFile.c_str(), "rb");
+        f = ssfopen(importFile, "rb");
         if(!f) goto err;
 
         uint8_t header[8];

src/ttf.cpp

@@ -246,7 +246,7 @@ bool TtfFont::LoadFontFromFile(bool nameOnly) {
 
     int i;
 
-    fh = fopen(fontFile.c_str(), "rb");
+    fh = ssfopen(fontFile, "rb");
     if(!fh) {
         return false;
     }

src/unix/unixutil.cpp

@@ -30,6 +30,18 @@ void dbp(const char *str, ...)
     fputc('\n', stderr);
 }
 
+FILE *ssfopen(const std::string &filename, const char *mode)
+{
+    if(filename.length() != strlen(filename.c_str())) oops();
+    return fopen(filename.c_str(), mode);
+}
+
+void ssremove(const std::string &filename)
+{
+    if(filename.length() != strlen(filename.c_str())) oops();
+    remove(filename.c_str());
+}
+
 int64_t GetUnixTime(void)
 {
     time_t ret;

src/win32/w32util.cpp

@@ -67,6 +67,26 @@ std::wstring Widen(const std::string &in)
     return out;
 }
 
+FILE *ssfopen(const std::string &filename, const char *mode)
+{
+    // Prepend \\?\ UNC prefix unless already an UNC path.
+    // We never try to fopen paths that are not absolute or
+    // contain separators inappropriate for the platform;
+    // thus, it is always safe to prepend this prefix.
+    std::string uncFilename = filename;
+    if(uncFilename.substr(0, 2) != "\\\\")
+        uncFilename = "\\\\?\\" + uncFilename;
+
+    if(filename.length() != strlen(filename.c_str())) oops();
+    return _wfopen(Widen(uncFilename).c_str(), Widen(mode).c_str());
+}
+
+void ssremove(const std::string &filename)
+{
+    if(filename.length() != strlen(filename.c_str())) oops();
+    _wremove(Widen(filename).c_str());
+}
+
 //-----------------------------------------------------------------------------
 // A separate heap, on which we allocate expressions. Maybe a bit faster,
 // since no fragmentation issues whatsoever, and it also makes it possible