dynamically adding umount in C++

[Pierre_Bultingaire]

Hello,

I want to dynamically add in my project an external folder using a mountpoint in runtime (without creating a .umount file).
I tried using Unigine::Filesystem::addMount, but it didn't seem to work.
Can you provide an example of a use case in C++ for this use of mountpoints

Thanks!
Pierre

[devrom]

Hello Pierre,

you need to add a blob file with the desired path and the umount extension.
Calling createMount on the desired path will work then without creating an additional file.

1. umount_filepath = virtual_path + ".umount"
2. FileSystem::addBlobFile(umount_filepath)
3. FileSystem::createMount(absolute_path, virtual_path, access)

Best regards

[Pierre_Bultingaire]

Hello Devrom, thanks for your answer!

I tried using blob file, but I still can't get the result I want.
In fact, I don't want to create a .umount file on disk, but dynamically load an external folder that is specified during runtime depending on the path I'm giving to my program.

Thanks!
Pierre

[devrom]

Quote

I tried using blob file, but I still can't get the result I want.

Can you share a code sample?
 

Quote

In fact, I don't want to create a .umount file on disk, but dynamically load an external folder that is specified during runtime depending on the path I'm giving to my program.

That is our use case, too. A blob file is a binary representation of a file in memory. If you add a blob file without a counterpart existing on disk the file will only exist in memory. As soon as you call createMount the engine will write to the specified path with blob files having a higher priority than files on disk. Therefore, no file will be written to disk. At least thats my understanding of the engine internals.

 

[Pierre_Bultingaire]

Quote

Can you share a code sample?

std::string absolute_path = "D:/absolute/path";
auto virtual_path  = folderName + "/";
auto umount_filepath = virtual_path + folderName + ".umount";
auto blob = Unigine::FileSystem::addBlobFile(umount_filepath.c_str());
auto mount = Unigine::FileSystem::createMount(absolute_path.c_str(), virtual_path.c_str(), Unigine::FileSystemMount::ACCESS_READONLY);

According to your description of blob files, the .umount file will be created in memory and FileSystem::createMount will return nullptr because the "file" is already created.
Is there is way to dynamically specify the content (json) of the umount blobFile?

Thank you
Pierre

[devrom]

auto virtual_path  = folderName + "/";
auto umount_filepath = virtual_path + folderName + ".umount";

These paths need to be identical except for the extension. The root of your mount starts from the umount file. I think your virtual_path should be: folderName + "/" + folderName

Edited May 24, 2022 by devrom

[Pierre_Bultingaire]

We found the issue, we just replaced the virtual_path by the umount_filepath to have the same path like you said.

Thanks!