Struct EnvWrapper

pub struct EnvWrapper { /* private fields */ }

| An implementation of Env that forwards all | calls to another Env. | | May be useful to clients who wish to override | just part of the functionality of another Env.

Implementations

impl EnvWrapper

pub fn new(t: Rc<RefCell<dyn Env>>) -> Self

| Initialize an EnvWrapper that delegates | all calls to *t. |

pub fn target(&self) -> Rc<RefCell<dyn Env>>

| Return the target to which this Env forwards | all calls. |

Trait Implementations

impl CreateDir for EnvWrapper

fn create_dir(&mut self, d: &String) -> Status

| Create the specified directory. |

impl DeleteDir for EnvWrapper

fn delete_dir(&mut self, d: &String) -> Status

| Delete the specified directory. |

impl DeleteFile for EnvWrapper

fn delete_file(&mut self, f: &String) -> Status

| Delete the named file. |

impl Env for EnvWrapper

fn new_appendable_file( &mut self, fname: &String, result: *mut *mut Box<dyn WritableFile>, ) -> Status

fn posix_default(&mut self) -> Rc<RefCell<dyn Env>>

impl FileExists for EnvWrapper

fn file_exists(&mut self, f: &String) -> bool

| Returns true iff the named file exists. |

impl GetChildren for EnvWrapper

fn get_children(&mut self, dir: &String, r: *mut Vec<String>) -> Status

| Store in *result the names of the children of | the specified directory. | | The names are relative to “dir”. | | Original contents of *results are dropped.

impl GetFileSize for EnvWrapper

fn get_file_size(&mut self, f: &String, s: *mut u64) -> Status

| Store the size of fname in *file_size. |

impl GetTestDirectory for EnvWrapper

fn get_test_directory(&mut self, path: *mut String) -> Status

| *path is set to a temporary directory that | can be used for testing. It may or may not | have just been created. The directory may or | may not differ between runs of the same | process, but subsequent calls will return the | same directory.

impl LockFile for EnvWrapper

fn lock_file(&mut self, f: &String, l: *mut *mut Box<dyn FileLock>) -> Status

| Lock the specified file. Used to prevent | concurrent access to the same db by multiple | processes. On failure, stores nullptr in | *lock and returns non-OK. | | On success, stores a pointer to the object | that represents the acquired lock in *lock | and returns OK. The caller should call | UnlockFile(*lock) to release the lock. If | the process exits, the lock will be | automatically released. | | If somebody else already holds the lock, | finishes immediately with a failure. I.e., | this call does not wait for existing locks to | go away. | | May create the named file if it does not | already exist.

impl NewAppendableFile for EnvWrapper

fn new_appendable_file( &mut self, f: &String, r: *mut *mut Box<dyn WritableFile>, ) -> Status

| Create an object that either appends to an | existing file, or writes to a new file (if | the file does not exist to begin with). On | success, stores a pointer to the new file in | *result and returns OK. On failure stores | nullptr in *result and returns non-OK. | | The returned file will only be accessed by | one thread at a time. | | May return an IsNotSupportedError error if | this Env does not allow appending to an | existing file. Users of Env (including the | leveldb implementation) must be prepared to | deal with an Env that does not support | appending.

impl NewLogger for EnvWrapper

fn new_logger( &mut self, fname: &String, result: *mut *mut Box<dyn Logger>, ) -> Status

Create and return a log file for storing informational messages.

impl NewRandomAccessFile for EnvWrapper

fn new_random_access_file( &mut self, f: &String, r: *mut *mut Box<dyn RandomAccessFile>, ) -> Status

| Create an object supporting random-access | reads from the file with the specified name. | On success, stores a pointer to the new file | in *result and returns OK. On failure stores | nullptr in *result and returns non-OK. If | the file does not exist, returns a non-OK | status. Implementations should return | a NotFound status when the file does not | exist. | | The returned file may be concurrently | accessed by multiple threads.

impl NewSequentialFile for EnvWrapper

fn new_sequential_file( &mut self, f: &String, r: *mut *mut Box<dyn SequentialFile>, ) -> Status

| The following text is boilerplate that | forwards all methods to target(). |

impl NewWritableFile for EnvWrapper

fn new_writable_file( &mut self, f: &String, r: *mut *mut Box<dyn WritableFile>, ) -> Status

| Create an object that writes to a new file | with the specified name. Deletes any | existing file with the same name and creates | a new file. On success, stores a pointer to | the new file in *result and returns OK. On | failure stores nullptr in *result and returns | non-OK. | | The returned file will only be accessed by | one thread at a time.

impl NowMicros for EnvWrapper

fn now_micros(&mut self) -> u64

| Returns the number of micro-seconds | since some fixed point in time. Only | useful for computing deltas of time. |

impl RenameFile for EnvWrapper

fn rename_file(&mut self, s: &String, t: &String) -> Status

| Rename file src to target. |

impl Schedule for EnvWrapper

fn schedule(&mut self, f: fn(_0: *mut c_void) -> c_void, a: *mut c_void)

| Arrange to run “(*function)(arg)” once in | a background thread. | | “function” may run in an unspecified thread. | Multiple functions added to the same Env may | run concurrently in different threads. | | I.e., the caller may not assume that | background work items are serialized.

impl SleepForMicroseconds for EnvWrapper

fn sleep_for_microseconds(&mut self, micros: i32)

| Sleep/delay the thread for the prescribed | number of micro-seconds. |

impl StartThread for EnvWrapper

fn start_thread(&mut self, f: fn(_0: *mut c_void) -> c_void, a: *mut c_void)

| Start a new thread, invoking “function(arg)” | within the new thread. | | When “function(arg)” returns, the thread will | be destroyed.

impl UnlockFile for EnvWrapper

fn unlock_file(&mut self, l: *mut Box<dyn FileLock>) -> Status

| Release the lock acquired by a previous | successful call to LockFile. | | REQUIRES: lock was returned by a successful | LockFile() call | | REQUIRES: lock has not already been unlocked.