Function rustc_incremental::persist::file_format::read_file

pub fn read_file(
    report_incremental_info: bool, 
    path: &Path, 
    nightly_build: bool
) -> Result<Option<(Vec<u8>, usize)>>

Reads the contents of a file with a file header as defined in this module.

• Returns Ok(Some(data, pos)) if the file existed and was generated by a compatible compiler version. data is the entire contents of the file and pos points to the first byte after the header.
• Returns Ok(None) if the file did not exist or was generated by an incompatible version of the compiler.
• Returns Err(..) if some kind of IO error occurred while reading the file.