common: Add some file utils.

Supports more advanced file operations than we'd normally need.
Intended to be used by magic disk cache.

Signed-off-by: Hans-Kristian Arntzen <post@arntzen-software.no>

include/private/vkd3d_file_utils.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2022 Hans-Kristian Arntzen for Valve Corporation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifndef __VKD3D_FILE_UTILS_H
+#define __VKD3D_FILE_UTILS_H
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+struct vkd3d_memory_mapped_file
+{
+    void *mapped;
+    size_t mapped_size;
+};
+
+/* On failure, ensures the struct is cleared to zero.
+ * A reference to the file is kept through the memory mapping. */
+bool vkd3d_file_map_read_only(const char *path, struct vkd3d_memory_mapped_file *file);
+/* Clears out file on unmap. */
+void vkd3d_file_unmap(struct vkd3d_memory_mapped_file *file);
+bool vkd3d_file_rename_overwrite(const char *from_path, const char *to_path);
+bool vkd3d_file_rename_no_replace(const char *from_path, const char *to_path);
+bool vkd3d_file_delete(const char *path);
+FILE *vkd3d_file_open_exclusive_write(const char *path);
+
+#endif

libs/vkd3d-common/file_utils.c

@@ -0,0 +1,188 @@
+/*
+ * Copyright 2022 Hans-Kristian Arntzen for Valve Corporation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#define VKD3D_DBG_CHANNEL VKD3D_DBG_CHANNEL_API
+
+#include "vkd3d_file_utils.h"
+#include "vkd3d_debug.h"
+
+/* For disk cache. */
+#ifdef _WIN32
+#include <windows.h>
+#include <io.h>
+#else
+#include <unistd.h>
+#include <sys/mman.h>
+#include <errno.h>
+#endif
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdio.h>
+
+bool vkd3d_file_rename_overwrite(const char *from_path, const char *to_path)
+{
+#ifdef _WIN32
+    DWORD code = ERROR_SUCCESS;
+
+    if (!MoveFileA(from_path, to_path))
+    {
+        code = GetLastError();
+        if (code == ERROR_ALREADY_EXISTS)
+        {
+            code = ERROR_SUCCESS;
+            if (!ReplaceFileA(to_path, from_path, NULL, 0, NULL, NULL))
+                code = GetLastError();
+        }
+    }
+
+    return code == ERROR_SUCCESS;
+#else
+    return rename(from_path, to_path) == 0;
+#endif
+}
+
+bool vkd3d_file_rename_no_replace(const char *from_path, const char *to_path)
+{
+#ifdef _WIN32
+    DWORD code = ERROR_SUCCESS;
+    if (!MoveFileA(from_path, to_path))
+        code = GetLastError();
+    return code == ERROR_SUCCESS;
+#else
+    return renameat2(AT_FDCWD, from_path, AT_FDCWD, to_path, RENAME_NOREPLACE) == 0;
+#endif
+}
+
+bool vkd3d_file_delete(const char *path)
+{
+#ifdef _WIN32
+    DWORD code = ERROR_SUCCESS;
+    if (!DeleteFileA(path))
+        code = GetLastError();
+    return code == ERROR_SUCCESS;
+#else
+    return unlink(path) == 0;
+#endif
+}
+
+FILE *vkd3d_file_open_exclusive_write(const char *path)
+{
+#ifdef _WIN32
+    /* From Fossilize. AFAIK, there is no direct way to make this work with FILE interface, so have to roundtrip
+     * through jank POSIX layer.
+     * wbx kinda works, but Wine warns about it, despite it working anyways.
+     * Older MSVC runtimes do not support wbx. */
+    FILE *file = NULL;
+    int fd;
+    fd = _open(path, _O_BINARY | _O_WRONLY | _O_CREAT | _O_EXCL | _O_TRUNC | _O_SEQUENTIAL,
+            _S_IWRITE | _S_IREAD);
+    if (fd >= 0)
+    {
+        file = _fdopen(fd, "wb");
+        /* _fdopen takes ownership. */
+        if (!file)
+            _close(fd);
+    }
+    return file;
+#else
+    return fopen(path, "wbx");
+#endif
+}
+
+void vkd3d_file_unmap(struct vkd3d_memory_mapped_file *file)
+{
+    if (file->mapped)
+    {
+#ifdef _WIN32
+        UnmapViewOfFile(file->mapped);
+#else
+        munmap(file->mapped, file->mapped_size);
+#endif
+    }
+    memset(file, 0, sizeof(*file));
+}
+
+bool vkd3d_file_map_read_only(const char *path, struct vkd3d_memory_mapped_file *file)
+{
+#ifdef _WIN32
+    DWORD size_hi, size_lo;
+    HANDLE file_mapping;
+    HANDLE handle;
+#else
+    struct stat stat_buf;
+    int fd;
+#endif
+
+    file->mapped = NULL;
+    file->mapped_size = 0;
+
+#ifdef _WIN32
+    handle = CreateFileA(path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_DELETE, NULL,
+            OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
+            INVALID_HANDLE_VALUE);
+    if (handle == INVALID_HANDLE_VALUE)
+        goto out;
+
+    size_lo = GetFileSize(handle, &size_hi);
+    file->mapped_size = size_lo | (((uint64_t)size_hi) << 32);
+
+    file_mapping = CreateFileMappingA(handle, NULL, PAGE_READONLY, 0, 0, NULL);
+    if (file_mapping == INVALID_HANDLE_VALUE)
+        goto out;
+
+    file->mapped = MapViewOfFile(file_mapping, FILE_MAP_READ, 0, 0, file->mapped_size);
+    CloseHandle(file_mapping);
+    file_mapping = INVALID_HANDLE_VALUE;
+    if (!file->mapped)
+    {
+        ERR("Failed to MapViewOfFile for %s.\n", path);
+        goto out;
+    }
+
+out:
+    if (handle != INVALID_HANDLE_VALUE)
+        CloseHandle(handle);
+#else
+    fd = open(path, O_RDONLY);
+    if (fd < 0)
+        goto out;
+
+    if (fstat(fd, &stat_buf) < 0)
+    {
+        ERR("Failed to fstat pipeline cache.\n");
+        goto out;
+    }
+
+    /* Map private to make sure we get CoW behavior in case someone clobbers
+     * the cache while in flight. We need to read data directly out of the cache. */
+    file->mapped = mmap(NULL, stat_buf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (file->mapped != MAP_FAILED)
+        file->mapped_size = stat_buf.st_size;
+    else
+        goto out;
+
+out:
+    if (fd >= 0)
+        close(fd);
+#endif
+
+    if (!file->mapped)
+        file->mapped_size = 0;
+    return file->mapped != NULL;
+}

libs/vkd3d-common/meson.build

@@ -4,6 +4,7 @@ vkd3d_common_src = [
   'utf8.c',
   'profiling.c',
   'string.c',
+  'file_utils.c',
 ]
 
 vkd3d_common_lib = static_library('vkd3d_common', vkd3d_common_src, vkd3d_header_files,