Struct no_proto::NP_Factory

pub struct NP_Factory { /* fields omitted */ }

Factories are created from schemas. Once you have a factory you can use it to create new buffers or open existing ones.

The correct way to create a factory is to pass a JSON string schema into the static new method. Learn about schemas here.

Example

use no_proto::error::NP_Error;
use no_proto::NP_Factory;
 
let user_factory = NP_Factory::new(r#"{
    "type": "table",
    "columns": [
        ["name",   {"type": "string"}],
        ["pass",   {"type": "string"}],
        ["age",    {"type": "uint16"}],
        ["todos",  {"type": "list", "of": {"type": "string"}}]
    ]
}"#)?;
 
// user_factory can now be used to make or open buffers that contain the data in the schema.
 
// create new buffer
let mut user_buffer = user_factory.empty_buffer(None, None); // optional capacity, optional size
    
// set the "name" column of the table
user_buffer.deep_set("name", "Billy Joel".to_owned())?;
 
// set the first todo
user_buffer.deep_set("todos.0", "Write a rust library.".to_owned())?;
 
// close buffer 
let user_vec:Vec<u8> = user_buffer.close();
 
// open existing buffer for reading
let user_buffer_2 = user_factory.open_buffer(user_vec);
 
// read column value
let name_column = user_buffer_2.deep_get::<String>("name")?;
assert_eq!(name_column, Some(Box::new("Billy Joel".to_owned())));
 
// read first todo
let todo_value = user_buffer_2.deep_get::<String>("todos.0")?;
assert_eq!(todo_value, Some(Box::new("Write a rust library.".to_owned())));
 
// read second todo
let todo_value = user_buffer_2.deep_get::<String>("todos.1")?;
assert_eq!(todo_value, None);
 
// close buffer again
let user_vec: Vec<u8> = user_buffer_2.close();
// user_vec is a Vec<u8> with our data
 

Next Step

Read about how to use buffers to access, mutate and compact data.

Go to NP_Buffer docs

Implementations

impl NP_Factory

pub fn new(json_schema: &str) -> Result<NP_Factory, NP_Error>

Generate a new factory from the given schema.

This operation will fail if the schema provided is invalid or if the schema is not valid JSON. If it fails you should get a useful error message letting you know what the problem is.

pub fn open_buffer(&self, bytes: Vec<u8>) -> NP_Buffer

Open existing Vec as buffer for this factory.
This just moves the Vec into the buffer object, no deserialization is done here.

pub fn empty_buffer(
    &self,
    capacity: Option<usize>,
    ptr_size: Option<NP_Size>
) -> NP_Buffer

Generate a new empty buffer from this factory.

The first opional argument, capacity, can be used to set the space of the underlying Vec when it's created. If you know you're going to be putting lots of data into the buffer, it's a good idea to set this to a large number comparable to the amount of data you're putting in. The default is 1,024 bytes.

The second optional argument, ptr_size, controls how much address space you get in the buffer. NP_Size::U16 (the default) gives you an address space of just over 16KB but is more space efficeint since the address pointers are only 2 bytes each. NP_Size::U32 gives you an address space of just over 4GB, but the addresses take up twice as much space in the buffer. You can change the address size through compaction after the buffer is created, so it's fine to start with a smaller address space and convert it to a larger one later as needed. It's also possible to go the other way, you can convert larger address space down to a smaller one durring compaction.

Trait Implementations

impl Debug for NP_Factory

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.