Add filesystem API

1 files changed, 122 insertions, 0 deletions

diff --git a/src/filesystem.c b/src/filesystem.c
new file mode 100644
index 0000000..c3e8f10
--- /dev/null
+++ b/src/filesystem.c
@@ -0,0 +1,122 @@
+// Copyright 2007-2022 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#include "zix/filesystem.h"
+
+#include "index_range.h"
+#include "path_iter.h"
+#include "system.h"
+
+#include "zix/allocator.h"
+#include "zix/status.h"
+
+#ifdef _WIN32
+#  include <direct.h>
+#  include <io.h>
+#else
+#  include <unistd.h>
+#endif
+
+#include <fcntl.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+ZixStatus
+zix_create_directories(ZixAllocator* const allocator,
+                       const char* const   dir_path)
+{
+  if (!dir_path[0]) {
+    return ZIX_STATUS_BAD_ARG;
+  }
+
+  // Allocate a working copy of the path to chop along the way
+  const size_t path_len = strlen(dir_path);
+  char* const  path     = (char*)zix_malloc(allocator, path_len + 1U);
+  memcpy(path, dir_path, path_len + 1U);
+
+  // Start at the root directory (past any name)
+  ZixPathIter p = zix_path_begin(path);
+  while (p.state < ZIX_PATH_FILE_NAME) {
+    p = zix_path_next(path, p);
+  }
+
+  // Create each directory down the path
+  ZixStatus st = ZIX_STATUS_SUCCESS;
+  while (p.state != ZIX_PATH_END) {
+    const char old_end = path[p.range.end];
+
+    path[p.range.end] = '\0';
+    if (zix_file_type(path) != ZIX_FILE_TYPE_DIRECTORY) {
+      if ((st = zix_create_directory(path))) {
+        break;
+      }
+    }
+
+    path[p.range.end] = old_end;
+    p                 = zix_path_next(path, p);
+  }
+
+  zix_free(allocator, path);
+  return st;
+}
+
+ZixFileOffset
+zix_file_size(const char* const path)
+{
+  struct stat sb;
+  return stat(path, &sb) ? (off_t)0 : sb.st_size;
+}
+
+bool
+zix_file_equals(ZixAllocator* const allocator,
+                const char* const   path_a,
+                const char* const   path_b)
+{
+  if (!strcmp(path_a, path_b)) {
+    return true; // Paths match
+  }
+
+  errno = 0;
+
+  // Open files and get file information
+  const int   fd_a = zix_system_open_fd(path_a, O_RDONLY, 0);
+  const int   fd_b = zix_system_open_fd(path_b, O_RDONLY, 0);
+  struct stat stat_a;
+  struct stat stat_b;
+  if (fd_a < 0 || fd_b < 0 || fstat(fd_a, &stat_a) || fstat(fd_b, &stat_b)) {
+    zix_system_close_fds(fd_b, fd_a);
+    return false;
+  }
+
+  bool match = false;
+  if (stat_a.st_dev == stat_b.st_dev && stat_a.st_ino && stat_b.st_ino &&
+      stat_a.st_ino == stat_b.st_ino) {
+    match = true; // Fast path: paths refer to the same file
+  } else if (stat_a.st_size == stat_b.st_size) {
+    // Slow path: files have equal size, compare contents
+    const uint32_t size   = zix_system_page_size();
+    void* const    page_a = zix_aligned_alloc(allocator, size, size);
+    void* const    page_b = zix_aligned_alloc(allocator, size, size);
+
+    if (page_a && page_b) {
+      match = true;
+      for (ZixSystemCountReturn n = 0; (n = read(fd_a, page_a, size)) > 0;) {
+        if (read(fd_b, page_b, size) != n ||
+            !!memcmp(page_a, page_b, (size_t)n)) {
+          match = false;
+          break;
+        }
+      }
+    }
+
+    zix_aligned_free(allocator, page_b);
+    zix_aligned_free(allocator, page_a);
+  }
+
+  return !zix_system_close_fds(fd_b, fd_a) && match;
+}