Add process state

src/path.c

@@ -0,0 +1,46 @@
+#include "src/path.h"
+#include "src/fs.h"
+#include "src/memory.h"
+#include "src/string.h"
+#include "src/util.h"
+#include <stdint.h>
+
+path_t *path_open(const fs_node_t *root, const path_t *source, char *path) {
+  path_t *result = memory_allocate(sizeof(path_t));
+
+  char *path_components[PATH_DEPTH];
+  uint8_t path_length = (uint8_t)string_split(path, '/', PATH_DEPTH, path_components);
+  if (!string_empty(path_components[0])) {
+    for (uint8_t i = 0; i < source->depth; i++) {
+      result->stack[result->depth++] = fs_open_again(source->stack[i]);
+    }
+  }
+
+  for (uint8_t i = 0; i < path_length; i++) {
+    if (string_empty(path_components[i]) || string_equal(path_components[i], ".")) {
+      continue;
+    } else if (string_equal(path_components[i], "..")) {
+      if (result->depth) {
+        fs_close(result->stack[--result->depth]);
+      }
+    } else {
+      const fs_node_t *prev = result->depth ? result->stack[result->depth - 1] : root;
+      fs_node_t *next = prev->is_dir ? fs_open_by(prev, path_components[i]) : NUL;
+      if (!next || result->depth >= PATH_DEPTH) {
+        path_close(result);
+        return NUL;
+      } else {
+        result->stack[result->depth++] = next;
+      }
+    }
+  }
+
+  return result;
+}
+
+void path_close(path_t *path) {
+  for (uint64_t i = 0; i < path->depth; i++) {
+    fs_close(path->stack[i]);
+  }
+  memory_free(path);
+}