Trait flatdata::ResourceStorage
source · pub trait ResourceStorage: Debug {
// Required methods
fn subdir(&self, dir: &str) -> StorageHandle;
fn exists(&self, resource_name: &str) -> bool;
fn read_resource(&self, resource_name: &str) -> Result<&[u8], Error>;
fn create_output_stream(
&self,
resource_name: &str
) -> Result<Box<dyn Stream>>;
// Provided methods
fn read(
&self,
resource_name: &str,
schema: &str
) -> Result<&[u8], ResourceStorageError> { ... }
fn write(
&self,
resource_name: &str,
schema: &str,
data: &[u8]
) -> Result<()> { ... }
fn read_and_check_schema(
&self,
resource_name: &str,
expected_schema: &str
) -> Result<&[u8], ResourceStorageError> { ... }
}Expand description
Hierarchical Resource Storage
Manages and returns resources corresponding to their keys. Keys can be slash-separated(‘/’). Manages schema for each resource and checks it on query. Resource storage is expected to provide read-write access to resources.
Required Methods§
sourcefn subdir(&self, dir: &str) -> StorageHandle
fn subdir(&self, dir: &str) -> StorageHandle
Creates a resource storage at a given subdirectory.
sourcefn read_resource(&self, resource_name: &str) -> Result<&[u8], Error>
fn read_resource(&self, resource_name: &str) -> Result<&[u8], Error>
Reads a resource in storage and returns a pointer to its raw data.
This is a low level facility for opening and reading resources. Cf.
read for opening flatdata resources and checking the
corresponding schema.
sourcefn create_output_stream(&self, resource_name: &str) -> Result<Box<dyn Stream>>
fn create_output_stream(&self, resource_name: &str) -> Result<Box<dyn Stream>>
Creates a resource with given name and returns an output stream for writing to it.
Provided Methods§
sourcefn read(
&self,
resource_name: &str,
schema: &str
) -> Result<&[u8], ResourceStorageError>
fn read( &self, resource_name: &str, schema: &str ) -> Result<&[u8], ResourceStorageError>
Open a flatdata resource with given name and schema for reading.
Also checks if the schema matches the stored schema in the storage. The
schema is expected to be stored in the storage as another resource
with name {resource_name}.schema.
sourcefn write(&self, resource_name: &str, schema: &str, data: &[u8]) -> Result<()>
fn write(&self, resource_name: &str, schema: &str, data: &[u8]) -> Result<()>
Writes data of a flatdata resource with given name and schema to storage.
The schema will be stored as another resource under the name
{resource_name}.schema.
sourcefn read_and_check_schema(
&self,
resource_name: &str,
expected_schema: &str
) -> Result<&[u8], ResourceStorageError>
fn read_and_check_schema( &self, resource_name: &str, expected_schema: &str ) -> Result<&[u8], ResourceStorageError>
Implementation helper for read.
Uses the required method read_resource for open the corresponding
resource and its schema. It checks the integrity of data by
verifying that the size of resource matched the size specified in
the header. Also checks that the stored schema matches the provided
schema.