Struct config_file_handler::FileHandler

pub struct FileHandler<T> { /* fields omitted */ }

Struct for reading and writing config files.

Thread- and Process-Safety

It is safe to read and write the same file using FileHandlerconcurrently in multiple threads and/or processes.

Methods

impl<T> FileHandler<T>

fn open<S: AsRef<OsStr> + ?Sized>(
    name: &S,
    assert_writable: bool
) -> Result<FileHandler<T>, Error>

Constructor taking the required file name (not the full path) This function will return an error if the file does not exist.

This function tests whether it has write access to the file in the following locations in this order (see also an example config file flowchart):

1. current_bin_dir()
2. user_app_dir()
3. system_cache_dir()

Parameter assert_writable dictates if the file should be writable or not.

See Thread- and Process-Safety for notes on thread- and process-safety.

fn path(&self) -> &Path

Get the full path to the file.

impl<T> FileHandler<T> where
    T: Default + Serialize, 

fn new<S: AsRef<OsStr> + ?Sized>(
    name: &S,
    is_existing_file_writable: bool
) -> Result<FileHandler<T>, Error>

Constructor taking the required file name (not the full path) The config file will be initialised to a default if it does not exist.

This function tests whether it has read access to the file in the following locations in this order (see also an example config file flowchart):

1. current_bin_dir()
2. user_app_dir()
3. system_cache_dir()

Parameter is_existing_file_writable will assert that if the file pre-exists should it be also writable or not. (E.g. it is enough for crust-config file to merely exist as readable, but bootstrap-cache must be writable too if it exists, else no updation can happen).

See Thread- and Process-Safety for notes on thread- and process-safety.

impl<T> FileHandler<T> where
    T: DeserializeOwned, 

fn read_file(&self) -> Result<T, Error>

Read the contents of the file and decode it as JSON.

impl<T> FileHandler<T> where
    T: Serialize, 

fn write_file(&self, contents: &T) -> Result<(), Error>

Write contents to the file as JSON.