Split out Windows directory iteration code to a dir_iterator_t type

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 187 insertions, 0 deletions

diff --git a/lib/util/Makemodule.am b/lib/util/Makemodule.am
index 0a0e50e..8e9b01d 100644
--- a/lib/util/Makemodule.am
+++ b/lib/util/Makemodule.am
@@ -2,6 +2,7 @@ libutil_a_SOURCES = include/util/util.h include/util/str_table.h \
 	include/util/hash_table.h include/util/test.h include/util/rbtree.h \
 	include/util/array.h include/util/threadpool.h \
 	include/util/w32threadwrap.h include/util/mempool.h \
+	include/util/dir_iterator.h \
 	lib/util/src/str_table.c lib/util/src/alloc.c lib/util/src/rbtree.c \
 	lib/util/src/array.c lib/util/src/xxhash.c lib/util/src/hash_table.c \
 	lib/util/src/fast_urem_by_const.h lib/util/src/threadpool_serial.c \
@@ -14,6 +15,7 @@ libutil_a_CPPFLAGS = $(AM_CPPFLAGS)
 
 if WINDOWS
 libutil_a_CFLAGS += -DWINVER=0x0600 -D_WIN32_WINNT=0x0600
+libutil_a_SOURCES += lib/util/src/w32_dir_iterator.c
 endif
 
 if HAVE_PTHREAD
diff --git a/lib/util/src/w32_dir_iterator.c b/lib/util/src/w32_dir_iterator.c
new file mode 100644
index 0000000..1a330ae
--- /dev/null
+++ b/lib/util/src/w32_dir_iterator.c
@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * w32_dir_iterator.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "util/dir_iterator.h"
+#include "util/util.h"
+#include "sqfs/error.h"
+
+#include <windows.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define UNIX_EPOCH_ON_W32 11644473600UL
+#define W32_TICS_PER_SEC 10000000UL
+
+enum {
+	STATE_HAVE_ENTRY = 0,
+	STATE_NEED_ENTRY = 1,
+	STATE_ERROR = 2,
+	STATE_EOF = 3,
+};
+
+typedef struct {
+	dir_iterator_t base;
+
+	WIN32_FIND_DATAW ent;
+	HANDLE dirhnd;
+	int state;
+} dir_iterator_win32_t;
+
+static sqfs_s64 w32time_to_unix(const FILETIME *ft)
+{
+	sqfs_u64 w32ts;
+
+	w32ts = ft->dwHighDateTime;
+	w32ts <<= 32UL;
+	w32ts |= ft->dwLowDateTime;
+
+	w32ts /= W32_TICS_PER_SEC;
+
+	if (w32ts <= UNIX_EPOCH_ON_W32)
+		return -((sqfs_s64)(UNIX_EPOCH_ON_W32 - w32ts));
+
+	return w32ts - UNIX_EPOCH_ON_W32;
+}
+
+static int dir_iterator_next(dir_iterator_t *it, dir_entry_t **out)
+{
+	dir_iterator_win32_t *w32 = (dir_iterator_win32_t *)it;
+	dir_entry_t *ent = NULL;
+	DWORD length;
+
+	*out = NULL;
+
+	switch (w32->state) {
+	case STATE_HAVE_ENTRY:
+		break;
+	case STATE_NEED_ENTRY:
+		if (!FindNextFileW(w32->dirhnd, &w32->ent)) {
+			if (GetLastError() == ERROR_NO_MORE_FILES) {
+				w32->state = STATE_EOF;
+				return 1;
+			}
+			w32->state = STATE_ERROR;
+			return SQFS_ERROR_INTERNAL;
+		}
+
+		w32->state = STATE_HAVE_ENTRY;
+		break;
+	case STATE_EOF:
+		return 1;
+	default:
+		return SQFS_ERROR_INTERNAL;
+	}
+
+	/* allocate */
+	length = WideCharToMultiByte(CP_UTF8, 0, w32->ent.cFileName,
+				     -1, NULL, 0, NULL, NULL);
+	if (length <= 0) {
+		w32->state = STATE_ERROR;
+		return SQFS_ERROR_ALLOC;
+	}
+
+	ent = alloc_flex(sizeof(*ent), 1, length + 1);
+	if (ent == NULL) {
+		w32->state = STATE_ERROR;
+		return SQFS_ERROR_ALLOC;
+	}
+
+	/* convert and fill entry fields */
+	WideCharToMultiByte(CP_UTF8, 0, w32->ent.cFileName, -1,
+			    ent->name, length + 1, NULL, NULL);
+
+	if (w32->ent.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
+		ent->mode = S_IFDIR | 0755;
+	} else {
+		ent->mode = S_IFREG | 0644;
+	}
+
+	ent->mtime = w32time_to_unix(&(w32->ent.ftLastWriteTime));
+
+	/* return and update state */
+	*out = ent;
+	w32->state = STATE_NEED_ENTRY;
+	return 0;
+}
+
+static void dir_iterator_destroy(sqfs_object_t *obj)
+{
+	dir_iterator_win32_t *dir = (dir_iterator_win32_t *)obj;
+
+	FindClose(dir->dirhnd);
+	free(dir);
+}
+
+dir_iterator_t *dir_iterator_create(const char *path)
+{
+	WCHAR *wpath = NULL, *new = NULL;
+	WIN32_FIND_DATAW first_entry;
+	dir_iterator_win32_t *it;
+	size_t len, newlen;
+	HANDLE dirhnd;
+
+	/* convert path to UTF-16, append "\\*" */
+	wpath = path_to_windows(path);
+	if (wpath == NULL) {
+		fprintf(stderr, "%s: allocation failure.\n", path);
+		return NULL;
+	}
+
+	for (len = 0; wpath[len] != '\0'; ++len)
+		;
+
+	newlen = len + 1;
+
+	if (len > 0 && wpath[len - 1] != '\\')
+		newlen += 1;
+
+	new = realloc(wpath, sizeof(wpath[0]) * (newlen + 1));
+	if (new == NULL) {
+		fprintf(stderr, "%s: allocation failure.\n", path);
+		free(wpath);
+		return NULL;
+	}
+
+	wpath = new;
+
+	if (len > 0 && wpath[len - 1] != '\\')
+		wpath[len++] = '\\';
+
+	wpath[len++] = '*';
+	wpath[len++] = '\0';
+
+	/* get the directory handle AND the first entry */
+	dirhnd = FindFirstFileW(wpath, &first_entry);
+
+	if (dirhnd == INVALID_HANDLE_VALUE) {
+		w32_perror(path);
+		free(wpath);
+		return NULL;
+	}
+
+	free(wpath);
+	wpath = NULL;
+
+	/* wrap it up */
+	it = calloc(1, sizeof(*it));
+	if (it == NULL) {
+		fprintf(stderr, "%s: allocation failure.\n", path);
+		FindClose(dirhnd);
+		return NULL;
+	}
+
+	sqfs_object_init(it, dir_iterator_destroy, NULL);
+
+	((dir_iterator_t *)it)->next = dir_iterator_next;
+
+	it->state = STATE_HAVE_ENTRY;
+	it->dirhnd = dirhnd;
+	it->ent = first_entry;
+	return (dir_iterator_t *)it;
+}