How to use IStorageProviderItemPropertySource.GetItemProperties method

Question

Need to fetch the StorageProviderItemProperty on a cloud file, but I don't see any ways to instantiate this class/interface/struct: "IStorageProviderItemPropertySource", do I need to implement anything of my own? Any instructions/documentation/sample code that can help me understand how to use it ?

Answer 1

Hi @Peter ,

The Windows.Storage APIs generally involve brokered I/O (read: slow) and are mainly still around to support older Universal Windows Platform (UWP) apps. Perhaps the Cloud Filter APIs are more useful to you? If not, can you share a bit more information on what you're trying to do?

main.rs

   use windows::*;  
   use windows::{  
       core::PCWSTR,  
       Win32::{  
           Foundation::MAX_PATH,  
           Storage::CloudFilters::{  
               CfGetPlaceholderInfo, CfOpenFileWithOplock, CF_OPEN_FILE_FLAG_NONE,  
               CF_PLACEHOLDER_INFO_STANDARD, CF_PLACEHOLDER_STANDARD_INFO,  
           },  
           System::Environment::ExpandEnvironmentStringsW,  
       },  
   };  
     
   fn main() -> windows::core::Result<()> {  
       unsafe {  
           let mut path = [0; MAX_PATH as usize];  
           ExpandEnvironmentStringsW(w!(r#"%OneDriveConsumer%\example.txt"#), Some(&mut path));  
     
           let handle = CfOpenFileWithOplock(PCWSTR::from_raw(&path as _), CF_OPEN_FILE_FLAG_NONE)?;  
     
           let mut buffer = [0u8; 2048];  
           CfGetPlaceholderInfo(handle, CF_PLACEHOLDER_INFO_STANDARD, &mut buffer, None)?;  
     
           let basic_info: CF_PLACEHOLDER_STANDARD_INFO = std::ptr::read(buffer.as_ptr() as *const _);  
     
           // Total number of bytes on disk.  
           println!("OnDiskDataSize (bytes): {}", basic_info.OnDiskDataSize);  
     
           // Total number of bytes that have been overwritten/appended locally that are not in sync with the cloud.  
           println!("ModifiedDataSize (bytes): {}", basic_info.ModifiedDataSize);  
     
           // Total number of bytes in sync with the cloud.  
           println!(  
               "ValidatedDataSize (bytes): {}",  
               basic_info.ValidatedDataSize  
           );  
       }  
     
       Ok(())  
   }  

Cargo.toml

   [package]  
   name = "app"  
   version = "0.0.0"  
   edition = "2018"  
   publish = false  
     
   [dependencies.windows]  
   version = "0.40.0"  
   features = [  
       "Win32_Foundation",  
       "Win32_Storage_CloudFilters",  
       "Win32_System_Environment",  
   ]  

Answer 2

Hello @WithinRafael

The placeholder info returned by Cloud Filter APIs doesn't contain the custom property I expect, what I want to is to fetch the custom property of a storage item being set by the SetAsync api here. Use cases like: I want to verify if SetAsync is done correctly, build logics around different states.
So I am wondering that: is "IStorageProviderItemPropertySource.GetItemProperties" the one I should use or there are some other ways? What're some code samples/instructions?

Thanks