T99807: Separate logic for changing working directory.

Set dir parameter to const for BLI_change_working_dir.
Added non-ASCII characters to the test directory.

Mac and Linux fixes. Linux now sets PWD when using BLI_change_working_dir. Mac uses NSFileManager through some new Mac-only wrapper functions.

Changed temporary directory to use a directory in the flags_test_asset_dir.
Ensure that operation to change working directory is from the main thread.

@@ -145,0 +148,4 @@
+ * Usage of this function is strongly discouraged as it is not thread safe. It will likely cause
+ * issues if there is an operation on another thread that does not expect the current working
+ * directory to change. This has been added to support USDZ export, which has a problematic
+ * "feature" described in this task https://developer.blender.org/D15623. It will be removed if it

@@ -313,6 +325,8 @@ void BLI_file_free_lines(struct LinkNode *lines);
  * Giving a path without leading `~` is not an error.
  */
 const char *BLI_expand_tilde(const char *path_with_tilde);
+const char *BLI_apple_getcwd(const size_t max_length);

@@ -39,1 +42,4 @@
 
+TEST(fileops, change_working_directory)
+{
+  BLI_threadapi_init();

@@ -40,0 +47,4 @@
+  char original_wd[FILE_MAX];
+  BLI_current_working_dir(original_wd, FILE_MAX);
+
+  const std::string test_temp_dir = blender::tests::flags_test_asset_dir() + "/" +

@@ -40,0 +55,4 @@
+  }
+
+  bool result = BLI_change_working_dir(test_temp_dir.c_str());
+  ASSERT_FALSE(result);

@@ -40,0 +65,4 @@
+  char cwd[FILE_MAX];
+  BLI_current_working_dir(cwd, FILE_MAX);
+
+  ASSERT_TRUE(BLI_path_cmp_normalized(cwd, test_temp_dir.c_str()) == 0);

@@ -59,0 +65,4 @@
+  if (!BLI_is_dir(dir)) {
+    return false;
+  }
+#if defined(WIN32)

@@ -79,6 +103,7 @@ char *BLI_current_working_dir(char *dir, const size_t maxncpy)
   return getcwd(dir, maxncpy);
 #endif
 }
+#endif

@@ -57,2 +57,4 @@
+#include "BLI_threads.h"
 #include "BLI_utildefines.h"
 
+#if !defined(__APPLE__)

@@ -40,0 +52,4 @@
+  const std::string temp_file_name(std::tmpnam(nullptr));
+  const std::string test_temp_dir = temp_file_name + "_новый";
+
+  if (BLI_exists(test_temp_dir.c_str())) {

@@ -40,0 +63,4 @@
+
+  result = BLI_change_working_dir(test_temp_dir.c_str());
+  ASSERT_TRUE(result)
+      << "temporary directory should have been created and should succeed changing directory.";

@@ -40,0 +78,4 @@
+  ASSERT_TRUE(result)
+      << "changing directory back to the original working directory should succeed.";
+
+  BLI_delete(test_temp_dir.c_str(), true, false);

@@ -40,0 +80,4 @@
+
+  BLI_delete(test_temp_dir.c_str(), true, false);
+
+  BLI_threadapi_exit();