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solve script matches with templates using op_if #69

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solve script matches with templates using op_if #69

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96 changes: 57 additions & 39 deletions src/script/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,13 +25,65 @@ pub use script_template::*;
#[derive(Debug, Default, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct Script(pub(crate) Vec<ScriptBit>);

pub struct ScriptIter<'a> {
scriptbit_iter: Vec<Iter<'a, ScriptBit>>,
}

impl<'a> Iterator for ScriptIter<'a> {
type Item = &'a ScriptBit;

fn next(&mut self) -> Option<&'a ScriptBit> {
let next = loop {
match self.scriptbit_iter.last_mut() {
None => return None,
Some(last) => {
match last.next() {
Some(next) => break next,
_ => ()
}
}
}
self.scriptbit_iter.pop();
};
match next {
ScriptBit::If { code, pass, fail } => {
static SCRIPTBITS_ENDIF: &'static [ScriptBit; 1] = &[ScriptBit::OpCode(OpCodes::OP_ENDIF)];
self.scriptbit_iter.push(SCRIPTBITS_ENDIF.iter());
if let Some(fail) = fail {
self.scriptbit_iter.push(fail.iter());
static SCRIPTBITS_ELSE: &'static [ScriptBit; 1] = &[ScriptBit::OpCode(OpCodes::OP_ELSE)];
self.scriptbit_iter.push(SCRIPTBITS_ELSE.iter());
}
self.scriptbit_iter.push(pass.iter());
match *code {
OpCodes::OP_IF => Some(&ScriptBit::OpCode(OpCodes::OP_IF)),
OpCodes::OP_NOTIF => Some(&ScriptBit::OpCode(OpCodes::OP_NOTIF)),
OpCodes::OP_VERIF => Some(&ScriptBit::OpCode(OpCodes::OP_VERIF)),
OpCodes::OP_VERNOTIF => Some(&ScriptBit::OpCode(OpCodes::OP_VERNOTIF)),
_ => Some(&ScriptBit::OpCode(OpCodes::OP_NOP)) // error?
}
},
x => Some(x)
}
}
}

/**
* Serialise Methods
*/
impl Script {
fn script_bits_iter(codes: &[ScriptBit]) -> ScriptIter {
ScriptIter {
scriptbit_iter: vec!(codes.iter()),
}
}

pub fn iter(&self) -> ScriptIter {
Script::script_bits_iter(&self.0)
}

fn script_bits_to_asm_string(codes: &[ScriptBit], extended: bool) -> String {
codes
.iter()
Script::script_bits_iter(codes)
.map(|x| match x {
ScriptBit::OpCode(OP_0) => match extended {
true => OP_0.to_string(),
Expand All @@ -46,37 +98,15 @@ impl Script {
false => hex::encode(bytes),
},
ScriptBit::OpCode(code) => code.to_string(),
ScriptBit::If { code, pass, fail } => {
let mut string_parts = vec![];

string_parts.push(code.to_string());

let pass_string = Script::script_bits_to_asm_string(pass, extended);
if !pass_string.is_empty() {
string_parts.push(pass_string);
}

if let Some(fail) = fail {
string_parts.push(OpCodes::OP_ELSE.to_string());
let fail_string = Script::script_bits_to_asm_string(fail, extended);
if !fail_string.is_empty() {
string_parts.push(fail_string);
}
}

string_parts.push(OpCodes::OP_ENDIF.to_string());

string_parts.join(" ")
}
ScriptBit::If { code:_, pass:_, fail:_ } => "".to_string(), // "iter" removes ScriptBit::If
ScriptBit::Coinbase(bytes) => hex::encode(bytes),
})
.collect::<Vec<String>>()
.join(" ")
}

pub fn script_bits_to_bytes(codes: &[ScriptBit]) -> Vec<u8> {
let bytes = codes
.iter()
let bytes = Script::script_bits_iter(codes)
.flat_map(|x| match x {
ScriptBit::OpCode(code) => vec![*code as u8],
ScriptBit::Push(bytes) => {
Expand All @@ -96,19 +126,7 @@ impl Script {
pushbytes.extend(bytes);
pushbytes
}
ScriptBit::If { code, pass, fail } => {
let mut bytes = vec![*code as u8];

bytes.extend_from_slice(&Script::script_bits_to_bytes(pass));

if let Some(fail) = fail {
bytes.push(OpCodes::OP_ELSE as u8);
bytes.extend_from_slice(&Script::script_bits_to_bytes(fail));
}
bytes.push(OpCodes::OP_ENDIF as u8);

bytes
}
ScriptBit::If { code:_, pass:_, fail:_ } => vec!(), // "iter" removes ScriptBit::If
ScriptBit::Coinbase(bytes) => bytes.to_vec(),
})
.collect();
Expand Down
15 changes: 9 additions & 6 deletions src/script/script_template.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -166,13 +166,16 @@ impl ScriptTemplate {
*/
impl Script {
pub fn match_impl(&self, script_template: &ScriptTemplate) -> Result<Vec<(MatchDataTypes, Vec<u8>)>, ScriptTemplateErrors> {
if self.0.len() != script_template.0.len() {
return Err(ScriptTemplateErrors::LengthsDiffer);
}

let mut matches = vec![];

for (i, (template, script)) in script_template.0.iter().zip(self.0.iter()).enumerate() {
let mut script_iter = self.iter();
let mut template_iter = script_template.0.iter().enumerate();

loop {
let (i, template, script) = match (template_iter.next(), script_iter.next()) {
(Some((i,t)),Some(s)) => (i,t,s),
(None,None) => break,
_ => return Err(ScriptTemplateErrors::LengthsDiffer)
};
let is_match = match (template, script) {
(MatchToken::OpCode(tmpl_code), ScriptBit::OpCode(op_code)) => Ok(tmpl_code == op_code),
(MatchToken::Push(tmpl_data), ScriptBit::Push(data)) => Ok(*tmpl_data == *data),
Expand Down
10 changes: 10 additions & 0 deletions tests/script.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -519,4 +519,14 @@ mod script_tests {

assert_eq!(&script.to_asm_string(), "OP_RETURN 0 01 0 00 00 00 00 00 00 00 00 00000000")
}

#[test]
fn byte_serialization_with_if() {
let asm = "OP_1 OP_IF OP_1 OP_ELSE OP_0 OP_ENDIF OP_DROP";
let script = Script::from_asm_string(&asm).unwrap();
let script_bytes = script.to_bytes();
let script2 = Script::from_bytes(&script_bytes).unwrap();
let script2_asm = script2.to_extended_asm_string();
assert_eq!(asm, script2_asm);
}
}
9 changes: 9 additions & 0 deletions tests/script_template.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,15 @@ mod script_template_tests {
assert_eq!(script.is_match(&script_template), false);
}

#[test]
fn op_if_does_match_template() {
let asm = "OP_1 OP_IF OP_1 OP_ELSE OP_0 OP_ENDIF OP_DROP";
let script = Script::from_asm_string(&asm).unwrap();
let script_template = ScriptTemplate::from_asm_string(&asm).unwrap();
println!("ref {:?} {:?}", script, script_template);
assert_eq!(script.is_match(&script_template), true);
}

#[test]
fn exact_script_template_matches_script_without_extracting_data() {
let script =
Expand Down