msvc: Add dirent.h/.c implementation

This fixes the build after adding directory iteration in d874702f

windows/msvc/dirent.c

+/*
+* This file is part of the MicroPython project, http://micropython.org/
+*
+* The MIT License (MIT)
+*
+* Copyright (c) 2015 Damien P. George
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+* THE SOFTWARE.
+*/
+
+#include "dirent.h"
+#include <errno.h>
+#include <Windows.h>
+
+typedef struct DIR {
+    HANDLE findHandle;
+    WIN32_FIND_DATA findData;
+    struct dirent result;
+} DIR;
+
+DIR *opendir(const char *name) {
+    if (!name || !*name) {
+        errno = ENOENT;
+        return NULL;
+    }
+
+    DIR *dir = malloc(sizeof(DIR));
+    if (!dir) {
+      errno = ENOMEM;
+      return NULL;
+    }
+    dir->result.d_ino = 0;
+    dir->result.d_name = NULL;
+    dir->findHandle = INVALID_HANDLE_VALUE;
+
+    const size_t nameLen = strlen(name);
+    char *path = malloc(nameLen + 3); // allocate enough for adding "/*"
+    if (!path) {
+      free(dir);
+      errno = ENOMEM;
+      return NULL;
+    }
+    strcpy(path, name);
+
+    // assure path ends with wildcard
+    const char lastChar = path[nameLen - 1];
+    if (lastChar != '*') {
+        const char *appendWC = (lastChar != '/' && lastChar != '\\') ? "/*" : "*";
+        strcat(path, appendWC);
+    }
+
+    // init
+    dir->findHandle = FindFirstFile(path, &dir->findData);
+    free(path);
+    if (dir->findHandle == INVALID_HANDLE_VALUE) {
+      free(dir);
+      errno = ENOENT;
+      return NULL;
+    }
+    return dir;
+}
+
+int closedir(DIR *dir) {
+    if (dir) {
+        FindClose(dir->findHandle);
+        free(dir);
+        return 0;
+    } else {
+        errno = EBADF;
+        return -1;
+    }
+}
+
+struct dirent *readdir(DIR *dir) {
+    if (!dir) {
+        errno = EBADF;
+        return NULL;
+    }
+
+    // first pass d_name is NULL so use result from FindFirstFile in opendir, else use FindNextFile
+    if (!dir->result.d_name || FindNextFile(dir->findHandle, &dir->findData)) {
+        dir->result.d_name = dir->findData.cFileName;
+        return &dir->result;
+    }
+
+    return NULL;
+}

windows/msvc/dirent.h

+/*
+* This file is part of the MicroPython project, http://micropython.org/
+*
+* The MIT License (MIT)
+*
+* Copyright (c) 2015 Damien P. George
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+* THE SOFTWARE.
+*/
+
+// dirent.h implementation for msvc
+
+// for ino_t
+#include <sys/types.h>
+
+// opaque DIR structure
+typedef struct DIR DIR;
+
+// the dirent structure
+// d_ino is always 0 - if ever needed use GetFileInformationByHandle
+typedef struct dirent {
+    ino_t d_ino;
+    char *d_name;
+} dirent;
+
+DIR *opendir(const char *name);
+int closedir(DIR *dir);
+struct dirent *readdir(DIR *dir);