[SHELL32] Show "size on disk" in file/folder properties

[ghost]

Purpose

• Current design of ReactOS shows blank "size on disk" field in file & folders properties dialog from Explorer
• Current design does not take credit of C++ functions for String management (using CString class)
• Current design use MAX_PATH sized buffers for strings not related to file path.

JIRA issue: CORE-12559

Proposed changes

• Implement computation and display of "size on disk", following recommendation from @Extravert-ir (Differs from initial code proposed by @amber8706 in comments of the Jira Ticket https://jira.reactos.org/browse/CORE-12559 )
• Refactoring of the recursive routine using CString, following recommendation from @learn-more

[binarymaster]

This code has been proposed by Amber in comments of the Jira Ticket

Cc @amber8706 🙂

[ghost]

Ready to go ?

[Extravert-ir]

This is a wrong approach to get "size on disk" information about a file.
"Size on disk" is what filesystem driver is responsible for and only it can reliably tell you how many bytes are reserved on disk for this file (for example, small files can be combined into one sector, files can be compressed, etc)

The right way is to use GetFileInformationByHandleEx API for that
https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-getfileinformationbyhandleex

[ghost]

This is a wrong approach to get "size on disk" information about a file.
"Size on disk" is what filesystem driver is responsible for and only it can reliably tell you how many bytes are reserved on disk for this file (for example, small files can be combined into one sector, files can be compressed, etc)

The right way is to use GetFileInformationByHandleEx API for that
https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-getfileinformationbyhandleex

Yes but the part of API we'd need is Vista+ only : https://docs.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_allocation_info

From a dev perspective, would you recommend to use this even in a NT5.2 compatibility context ?

[Extravert-ir]

Yes but the part of API we'd need is Vista+ only

You have two options here: use the function from kernel32_vista or manually call NtQueryInformationFile

[HBelusca]

Can't GetFileInformationByHandle (not ex) be used too? As you know, Windows 2000/XP/2003 are able to show an estimation of "Show size on disk" even when they don't have this -Ex API.

[ghost]

Can't GetFileInformationByHandle (not ex) be used too? As you know, Windows 2000/XP/2003 are able to show an estimation of "Show size on disk" even when they don't have this -Ex API.

Looking at GetFileInformationByHandle here : https://docs.microsoft.com/en-us/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information it seems that only logical size is returned

[ghost]

Would it be possible to merge now that no more comments are open ?

[ghost]

Now using HeapAlloc/HeapFree rather than fixed size array... and the code now crashes.
Help needed.

[ghost]

To be rewritten with CString as per discussion with @learn-more

[ghost]

Reverted to MAX_PATH as discussed with @learn-more in Mattermost. Moving to dynamic buffers everywhere will be a dedicated PR.

Current implementation works fine on "C:\ReactOS" (including sub-folders) but does not work properly with "c:\Documents and Settings", raising

err:(dll/win32/shell32/dialogs/filedefext.cpp:1399) FindFirstFileW C:\Documents and Settings\?Default User\* failed
err:(dll/win32/shell32/dialogs/filedefext.cpp:1399) FindFirstFileW C:\Documents and Settings\?All Users\* failed
err:(dll/win32/shell32/dialogs/filedefext.cpp:1399) FindFirstFileW C:\Documents and Settings\?NetworkService\* failed
err:(dll/win32/shell32/dialogs/filedefext.cpp:1399) FindFirstFileW C:\Documents and Settings\?Administrator\* failed

Under investigation (where does this damn "?" comes from....)

[learn-more]

Please fix the memory leaks, the nit is up to you if you want to change it