Trait opendal::raw::Access

pub trait Access: Send + Sync + Debug + Unpin + 'static {
    type Reader: Read;
    type Writer: Write;
    type Lister: List;
    type BlockingReader: BlockingRead;
    type BlockingWriter: BlockingWrite;
    type BlockingLister: BlockingList;

    // Required method
    fn info(&self) -> Arc<AccessorInfo>;

    // Provided methods
    fn create_dir(
        &self,
        path: &str,
        args: OpCreateDir,
    ) -> impl Future<Output = Result<RpCreateDir>> + MaybeSend { ... }
    fn stat(
        &self,
        path: &str,
        args: OpStat,
    ) -> impl Future<Output = Result<RpStat>> + MaybeSend { ... }
    fn read(
        &self,
        path: &str,
        args: OpRead,
    ) -> impl Future<Output = Result<(RpRead, Self::Reader)>> + MaybeSend { ... }
    fn write(
        &self,
        path: &str,
        args: OpWrite,
    ) -> impl Future<Output = Result<(RpWrite, Self::Writer)>> + MaybeSend { ... }
    fn delete(
        &self,
        path: &str,
        args: OpDelete,
    ) -> impl Future<Output = Result<RpDelete>> + MaybeSend { ... }
    fn list(
        &self,
        path: &str,
        args: OpList,
    ) -> impl Future<Output = Result<(RpList, Self::Lister)>> + MaybeSend { ... }
    fn copy(
        &self,
        from: &str,
        to: &str,
        args: OpCopy,
    ) -> impl Future<Output = Result<RpCopy>> + MaybeSend { ... }
    fn rename(
        &self,
        from: &str,
        to: &str,
        args: OpRename,
    ) -> impl Future<Output = Result<RpRename>> + MaybeSend { ... }
    fn presign(
        &self,
        path: &str,
        args: OpPresign,
    ) -> impl Future<Output = Result<RpPresign>> + MaybeSend { ... }
    fn batch(
        &self,
        args: OpBatch,
    ) -> impl Future<Output = Result<RpBatch>> + MaybeSend { ... }
    fn blocking_create_dir(
        &self,
        path: &str,
        args: OpCreateDir,
    ) -> Result<RpCreateDir> { ... }
    fn blocking_stat(&self, path: &str, args: OpStat) -> Result<RpStat> { ... }
    fn blocking_read(
        &self,
        path: &str,
        args: OpRead,
    ) -> Result<(RpRead, Self::BlockingReader)> { ... }
    fn blocking_write(
        &self,
        path: &str,
        args: OpWrite,
    ) -> Result<(RpWrite, Self::BlockingWriter)> { ... }
    fn blocking_delete(&self, path: &str, args: OpDelete) -> Result<RpDelete> { ... }
    fn blocking_list(
        &self,
        path: &str,
        args: OpList,
    ) -> Result<(RpList, Self::BlockingLister)> { ... }
    fn blocking_copy(
        &self,
        from: &str,
        to: &str,
        args: OpCopy,
    ) -> Result<RpCopy> { ... }
    fn blocking_rename(
        &self,
        from: &str,
        to: &str,
        args: OpRename,
    ) -> Result<RpRename> { ... }
}

Underlying trait of all backends for implementers.

The actual data access of storage service happens in Accessor layer. Every storage supported by OpenDAL must implement Access but not all methods of Access will be implemented according to how the storage service is.

For example, user can not modify the content from one HTTP file server directly. So Http implements and provides only read related actions.

Access gives default implementation for all methods which will raise ErrorKind::Unsupported error. And what action this Access supports will be pointed out in AccessorInfo.

Note

Visit internals for more tutorials.

Operations

• Path in args will all be normalized into the same style, services should handle them based on services’ requirement.
  • Path that ends with / means it’s Dir, otherwise, it’s File.
  • Root dir is /
  • Path will never be empty.
• Operations without capability requirement like metadata, create are basic operations.
  • All services must implement them.
  • Use unimplemented!() if not implemented or can’t implement.
• Operations with capability requirement like presign are optional operations.
  • Services can implement them based on services capabilities.
  • The default implementation should return ErrorKind::Unsupported.

Required Associated Types

type Reader: Read

Reader is the associated reader returned in read operation.

type Writer: Write

Writer is the associated writer returned in write operation.

type Lister: List

Lister is the associated lister returned in list operation.

type BlockingReader: BlockingRead

BlockingReader is the associated reader returned blocking_read operation.

type BlockingWriter: BlockingWrite

BlockingWriter is the associated writer returned blocking_write operation.

type BlockingLister: BlockingList

BlockingLister is the associated lister returned blocking_list operation.

Required Methods

fn info(&self) -> Arc<AccessorInfo>

Invoke the info operation to get metadata of accessor.

Notes

This function is required to be implemented.

By returning AccessorInfo, underlying services can declare some useful information about it self.

• scheme: declare the scheme of backend.
• capabilities: declare the capabilities of current backend.

Provided Methods

fn create_dir( &self, path: &str, args: OpCreateDir, ) -> impl Future<Output = Result<RpCreateDir>> + MaybeSend

Invoke the create operation on the specified path

Require Capability::create_dir

Behavior

• Input path MUST match with EntryMode, DON’T NEED to check mode.
• Create on existing dir SHOULD succeed.

fn stat( &self, path: &str, args: OpStat, ) -> impl Future<Output = Result<RpStat>> + MaybeSend

Invoke the stat operation on the specified path.

Require Capability::stat

Behavior

• stat empty path means stat backend’s root path.
• stat a path endswith “/” means stating a dir.
• mode and content_length must be set.

fn read( &self, path: &str, args: OpRead, ) -> impl Future<Output = Result<(RpRead, Self::Reader)>> + MaybeSend

Invoke the read operation on the specified path, returns a Reader if operate successful.

Require Capability::read

Behavior

• Input path MUST be file path, DON’T NEED to check mode.
• The returning content length may be smaller than the range specified.

fn write( &self, path: &str, args: OpWrite, ) -> impl Future<Output = Result<(RpWrite, Self::Writer)>> + MaybeSend

Invoke the write operation on the specified path, returns a written size if operate successful.

Require Capability::write

Behavior

• Input path MUST be file path, DON’T NEED to check mode.

fn delete( &self, path: &str, args: OpDelete, ) -> impl Future<Output = Result<RpDelete>> + MaybeSend

Invoke the delete operation on the specified path.

Require Capability::delete

Behavior

• delete is an idempotent operation, it’s safe to call Delete on the same path multiple times.
• delete SHOULD return Ok(()) if the path is deleted successfully or not exist.

fn list( &self, path: &str, args: OpList, ) -> impl Future<Output = Result<(RpList, Self::Lister)>> + MaybeSend

Invoke the list operation on the specified path.

Require Capability::list

Behavior

• Input path MUST be dir path, DON’T NEED to check mode.
• List non-exist dir should return Empty.

fn copy( &self, from: &str, to: &str, args: OpCopy, ) -> impl Future<Output = Result<RpCopy>> + MaybeSend

Invoke the copy operation on the specified from path and to path.

Require Capability::copy

Behaviour

• from and to MUST be file path, DON’T NEED to check mode.
• Copy on existing file SHOULD succeed.
• Copy on existing file SHOULD overwrite and truncate.

fn rename( &self, from: &str, to: &str, args: OpRename, ) -> impl Future<Output = Result<RpRename>> + MaybeSend

Invoke the rename operation on the specified from path and to path.

Require Capability::rename

fn presign( &self, path: &str, args: OpPresign, ) -> impl Future<Output = Result<RpPresign>> + MaybeSend

Invoke the presign operation on the specified path.

Require Capability::presign

Behavior

• This API is optional, return std::io::ErrorKind::Unsupported if not supported.

fn batch( &self, args: OpBatch, ) -> impl Future<Output = Result<RpBatch>> + MaybeSend

Invoke the batch operations.

Require Capability::batch

fn blocking_create_dir( &self, path: &str, args: OpCreateDir, ) -> Result<RpCreateDir>

Invoke the blocking_create operation on the specified path.

This operation is the blocking version of Accessor::create_dir

Require Capability::create_dir and Capability::blocking

fn blocking_stat(&self, path: &str, args: OpStat) -> Result<RpStat>

Invoke the blocking_stat operation on the specified path.

This operation is the blocking version of Accessor::stat

Require Capability::stat and Capability::blocking

fn blocking_read( &self, path: &str, args: OpRead, ) -> Result<(RpRead, Self::BlockingReader)>

Invoke the blocking_read operation on the specified path.

This operation is the blocking version of Accessor::read

Require Capability::read and Capability::blocking

fn blocking_write( &self, path: &str, args: OpWrite, ) -> Result<(RpWrite, Self::BlockingWriter)>

Invoke the blocking_write operation on the specified path.

This operation is the blocking version of Accessor::write

Require Capability::write and Capability::blocking

fn blocking_delete(&self, path: &str, args: OpDelete) -> Result<RpDelete>

Invoke the blocking_delete operation on the specified path.

This operation is the blocking version of Accessor::delete

Require Capability::write and Capability::blocking

fn blocking_list( &self, path: &str, args: OpList, ) -> Result<(RpList, Self::BlockingLister)>

Invoke the blocking_list operation on the specified path.

This operation is the blocking version of Accessor::list

Require Capability::list and Capability::blocking

Behavior

• List non-exist dir should return Empty.

fn blocking_copy(&self, from: &str, to: &str, args: OpCopy) -> Result<RpCopy>

Invoke the blocking_copy operation on the specified from path and to path.

This operation is the blocking version of Accessor::copy

Require Capability::copy and Capability::blocking

fn blocking_rename( &self, from: &str, to: &str, args: OpRename, ) -> Result<RpRename>

Invoke the blocking_rename operation on the specified from path and to path.

This operation is the blocking version of Accessor::rename

Require Capability::rename and Capability::blocking

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl Access for ()

Dummy implementation of accessor.

type Reader = ()

type Writer = ()

type Lister = ()

type BlockingReader = ()

type BlockingWriter = ()

type BlockingLister = ()

fn info(&self) -> Arc<AccessorInfo>

impl<T: Access + ?Sized> Access for Arc<T>

All functions in Accessor only requires &self, so it’s safe to implement Accessor for Arc<impl Access>.

type Reader = <T as Access>::Reader

type Writer = <T as Access>::Writer

type Lister = <T as Access>::Lister

type BlockingReader = <T as Access>::BlockingReader

type BlockingWriter = <T as Access>::BlockingWriter

type BlockingLister = <T as Access>::BlockingLister

fn info(&self) -> Arc<AccessorInfo>

fn create_dir( &self, path: &str, args: OpCreateDir, ) -> impl Future<Output = Result<RpCreateDir>> + MaybeSend

fn stat( &self, path: &str, args: OpStat, ) -> impl Future<Output = Result<RpStat>> + MaybeSend

fn read( &self, path: &str, args: OpRead, ) -> impl Future<Output = Result<(RpRead, Self::Reader)>> + MaybeSend

fn write( &self, path: &str, args: OpWrite, ) -> impl Future<Output = Result<(RpWrite, Self::Writer)>> + MaybeSend

fn delete( &self, path: &str, args: OpDelete, ) -> impl Future<Output = Result<RpDelete>> + MaybeSend

fn list( &self, path: &str, args: OpList, ) -> impl Future<Output = Result<(RpList, Self::Lister)>> + MaybeSend

fn copy( &self, from: &str, to: &str, args: OpCopy, ) -> impl Future<Output = Result<RpCopy>> + MaybeSend

fn rename( &self, from: &str, to: &str, args: OpRename, ) -> impl Future<Output = Result<RpRename>> + MaybeSend

fn presign( &self, path: &str, args: OpPresign, ) -> impl Future<Output = Result<RpPresign>> + MaybeSend

fn batch( &self, args: OpBatch, ) -> impl Future<Output = Result<RpBatch>> + MaybeSend

fn blocking_create_dir( &self, path: &str, args: OpCreateDir, ) -> Result<RpCreateDir>

fn blocking_stat(&self, path: &str, args: OpStat) -> Result<RpStat>

fn blocking_read( &self, path: &str, args: OpRead, ) -> Result<(RpRead, Self::BlockingReader)>

fn blocking_write( &self, path: &str, args: OpWrite, ) -> Result<(RpWrite, Self::BlockingWriter)>

fn blocking_delete(&self, path: &str, args: OpDelete) -> Result<RpDelete>

fn blocking_list( &self, path: &str, args: OpList, ) -> Result<(RpList, Self::BlockingLister)>

fn blocking_copy(&self, from: &str, to: &str, args: OpCopy) -> Result<RpCopy>

fn blocking_rename( &self, from: &str, to: &str, args: OpRename, ) -> Result<RpRename>

Implementors

impl Access for dyn AccessDyn

type Reader = Box<dyn ReadDyn>

type BlockingReader = Box<dyn BlockingRead>

type Writer = Box<dyn WriteDyn>

type BlockingWriter = Box<dyn BlockingWrite>

type Lister = Box<dyn ListDyn>

type BlockingLister = Box<dyn BlockingList>

impl<L: LayeredAccess> Access for L

type Reader = <L as LayeredAccess>::Reader

type Writer = <L as LayeredAccess>::Writer

type Lister = <L as LayeredAccess>::Lister

type BlockingReader = <L as LayeredAccess>::BlockingReader

type BlockingWriter = <L as LayeredAccess>::BlockingWriter

type BlockingLister = <L as LayeredAccess>::BlockingLister

impl<S: Adapter> Access for opendal::raw::adapters::kv::Backend<S>

type Reader = Buffer

type BlockingReader = Buffer

type Writer = KvWriter<S>

type BlockingWriter = KvWriter<S>

type Lister = HierarchyLister<KvLister<<S as Adapter>::Scanner>>

type BlockingLister = HierarchyLister<BlockingKvLister>

impl<S: Adapter> Access for opendal::raw::adapters::typed_kv::Backend<S>

type Reader = Buffer

type BlockingReader = Buffer

type Writer = KvWriter<S>

type BlockingWriter = KvWriter<S>

type Lister = HierarchyLister<KvLister>

type BlockingLister = HierarchyLister<KvLister>