use crate::{
cost_model::transferred_byte_cycles,
syscalls::{
utils::store_data, Source, SourceEntry, INDEX_OUT_OF_BOUND,
LOAD_CELL_DATA_AS_CODE_SYSCALL_NUMBER, LOAD_CELL_DATA_SYSCALL_NUMBER, SLICE_OUT_OF_BOUND,
SUCCESS,
},
};
use ckb_traits::CellDataProvider;
use ckb_types::core::cell::CellMeta;
use ckb_vm::{
memory::{Memory, FLAG_EXECUTABLE, FLAG_FREEZED},
registers::{A0, A1, A2, A3, A4, A5, A7},
Error as VMError, Register, SupportMachine, Syscalls,
};
pub struct LoadCellData<'a, DL> {
data_loader: &'a DL,
outputs: &'a [CellMeta],
resolved_inputs: &'a [CellMeta],
resolved_cell_deps: &'a [CellMeta],
group_inputs: &'a [usize],
group_outputs: &'a [usize],
}
impl<'a, DL: CellDataProvider + 'a> LoadCellData<'a, DL> {
pub fn new(
data_loader: &'a DL,
outputs: &'a [CellMeta],
resolved_inputs: &'a [CellMeta],
resolved_cell_deps: &'a [CellMeta],
group_inputs: &'a [usize],
group_outputs: &'a [usize],
) -> LoadCellData<'a, DL> {
LoadCellData {
data_loader,
outputs,
resolved_inputs,
resolved_cell_deps,
group_inputs,
group_outputs,
}
}
fn fetch_cell(&self, source: Source, index: usize) -> Result<&'a CellMeta, u8> {
match source {
Source::Transaction(SourceEntry::Input) => {
self.resolved_inputs.get(index).ok_or(INDEX_OUT_OF_BOUND)
}
Source::Transaction(SourceEntry::Output) => {
self.outputs.get(index).ok_or(INDEX_OUT_OF_BOUND)
}
Source::Transaction(SourceEntry::CellDep) => {
self.resolved_cell_deps.get(index).ok_or(INDEX_OUT_OF_BOUND)
}
Source::Transaction(SourceEntry::HeaderDep) => Err(INDEX_OUT_OF_BOUND),
Source::Group(SourceEntry::Input) => self
.group_inputs
.get(index)
.ok_or(INDEX_OUT_OF_BOUND)
.and_then(|actual_index| {
self.resolved_inputs
.get(*actual_index)
.ok_or(INDEX_OUT_OF_BOUND)
}),
Source::Group(SourceEntry::Output) => self
.group_outputs
.get(index)
.ok_or(INDEX_OUT_OF_BOUND)
.and_then(|actual_index| self.outputs.get(*actual_index).ok_or(INDEX_OUT_OF_BOUND)),
Source::Group(SourceEntry::CellDep) => Err(INDEX_OUT_OF_BOUND),
Source::Group(SourceEntry::HeaderDep) => Err(INDEX_OUT_OF_BOUND),
}
}
fn load_data_as_code<Mac: SupportMachine>(&self, machine: &mut Mac) -> Result<(), VMError> {
let addr = machine.registers()[A0].to_u64();
let memory_size = machine.registers()[A1].to_u64();
let content_offset = machine.registers()[A2].to_u64();
let content_size = machine.registers()[A3].to_u64();
let index = machine.registers()[A4].to_u64();
let source = Source::parse_from_u64(machine.registers()[A5].to_u64())?;
let cell = self.fetch_cell(source, index as usize);
if let Err(err) = cell {
machine.set_register(A0, Mac::REG::from_u8(err));
return Ok(());
}
let cell = cell.unwrap();
let content_end = content_offset
.checked_add(content_size)
.ok_or(VMError::MemOutOfBound)?;
if content_offset >= cell.data_bytes
|| content_end > cell.data_bytes
|| content_size > memory_size
{
machine.set_register(A0, Mac::REG::from_u8(SLICE_OUT_OF_BOUND));
return Ok(());
}
let data = self
.data_loader
.load_cell_data(cell)
.ok_or_else(|| {
VMError::Unexpected(format!(
"Unexpected load_cell_data failed {}",
cell.out_point,
))
})?
.slice((content_offset as usize)..(content_end as usize));
machine.memory_mut().init_pages(
addr,
memory_size,
FLAG_EXECUTABLE | FLAG_FREEZED,
Some(data),
0,
)?;
machine.add_cycles_no_checking(transferred_byte_cycles(memory_size))?;
machine.set_register(A0, Mac::REG::from_u8(SUCCESS));
Ok(())
}
fn load_data<Mac: SupportMachine>(&self, machine: &mut Mac) -> Result<(), VMError> {
let index = machine.registers()[A3].to_u64();
let source = Source::parse_from_u64(machine.registers()[A4].to_u64())?;
let cell = self.fetch_cell(source, index as usize);
if let Err(err) = cell {
machine.set_register(A0, Mac::REG::from_u8(err));
return Ok(());
}
let cell = cell.unwrap();
let data = self.data_loader.load_cell_data(cell).ok_or_else(|| {
VMError::Unexpected(format!(
"Unexpected load_cell_data failed {}",
cell.out_point,
))
})?;
let wrote_size = store_data(machine, &data)?;
machine.add_cycles_no_checking(transferred_byte_cycles(wrote_size))?;
machine.set_register(A0, Mac::REG::from_u8(SUCCESS));
Ok(())
}
}
impl<'a, Mac: SupportMachine, DL: CellDataProvider> Syscalls<Mac> for LoadCellData<'a, DL> {
fn initialize(&mut self, _machine: &mut Mac) -> Result<(), VMError> {
Ok(())
}
fn ecall(&mut self, machine: &mut Mac) -> Result<bool, VMError> {
let code = machine.registers()[A7].to_u64();
if code == LOAD_CELL_DATA_AS_CODE_SYSCALL_NUMBER {
self.load_data_as_code(machine)?;
return Ok(true);
} else if code == LOAD_CELL_DATA_SYSCALL_NUMBER {
self.load_data(machine)?;
return Ok(true);
}
Ok(false)
}
}