librustzcash/zcash_client_backend/src/proto.rs

//! Generated code for handling light client protobuf structs.

use ff::PrimeField;
use group::GroupEncoding;
use std::convert::TryInto;

use zcash_primitives::{
    block::{BlockHash, BlockHeader},
    consensus::BlockHeight,
};

pub mod compact_formats;

impl compact_formats::CompactBlock {
    /// Returns the [`BlockHash`] for this block.
    ///
    /// # Panics
    ///
    /// This function will panic if [`CompactBlock.header`] is not set and
    /// [`CompactBlock.hash`] is not exactly 32 bytes.
    ///
    /// [`CompactBlock.header`]: #structfield.header
    /// [`CompactBlock.hash`]: #structfield.hash
    pub fn hash(&self) -> BlockHash {
        if let Some(header) = self.header() {
            header.hash()
        } else {
            BlockHash::from_slice(&self.hash)
        }
    }

    /// Returns the [`BlockHash`] for this block's parent.
    ///
    /// # Panics
    ///
    /// This function will panic if [`CompactBlock.header`] is not set and
    /// [`CompactBlock.prevHash`] is not exactly 32 bytes.
    ///
    /// [`CompactBlock.header`]: #structfield.header
    /// [`CompactBlock.prevHash`]: #structfield.prevHash
    pub fn prev_hash(&self) -> BlockHash {
        if let Some(header) = self.header() {
            header.prev_block
        } else {
            BlockHash::from_slice(&self.prevHash)
        }
    }

    /// Returns the [`BlockHeight`] value for this block
    ///
    /// # Panics
    ///
    /// This function will panic if [`CompactBlock.height`] is not
    /// representable within a u32.
    pub fn height(&self) -> BlockHeight {
        self.height.try_into().unwrap()
    }

    /// Returns the [`BlockHeader`] for this block if present.
    ///
    /// A convenience method that parses [`CompactBlock.header`] if present.
    ///
    /// [`CompactBlock.header`]: #structfield.header
    pub fn header(&self) -> Option<BlockHeader> {
        if self.header.is_empty() {
            None
        } else {
            BlockHeader::read(&self.header[..]).ok()
        }
    }
}

impl compact_formats::CompactOutput {
    /// Returns the note commitment for this output.
    ///
    /// A convenience method that parses [`CompactOutput.cmu`].
    ///
    /// [`CompactOutput.cmu`]: #structfield.cmu
    pub fn cmu(&self) -> Result<bls12_381::Scalar, ()> {
        let mut repr = [0; 32];
        repr.as_mut().copy_from_slice(&self.cmu[..]);
        bls12_381::Scalar::from_repr(repr).ok_or(())
    }

    /// Returns the ephemeral public key for this output.
    ///
    /// A convenience method that parses [`CompactOutput.epk`].
    ///
    /// [`CompactOutput.epk`]: #structfield.epk
    pub fn epk(&self) -> Result<jubjub::ExtendedPoint, ()> {
        let p = jubjub::ExtendedPoint::from_bytes(&self.epk[..].try_into().map_err(|_| ())?);
        if p.is_some().into() {
            Ok(p.unwrap())
        } else {
            Err(())
        }
    }
}