Finish opcode optimality checks

Author: lucidLuckylee

src/lib.rs

@@ -19,9 +19,9 @@
 //! ```rust
 //! #![feature(proc_macro_hygiene)]
 //!
-//! use bitcoin_script::{script, define_pushable};
+//! # use bitcoin_script::{script, define_pushable};
 //!
-//! define_pushable!();
+//! # define_pushable!();
 //! # let digest = 0;
 //! # let seller_pubkey_hash = 0;
 //! # let buyer_pubkey_hash = 0;
@@ -59,7 +59,8 @@
 //!
 //! ```rust
 //! # #![feature(proc_macro_hygiene)]
-//! # use bitcoin_script::script;
+//! # use bitcoin_script::{script, define_pushable};
+//! # define_pushable!();
 //! let script = script!(OP_CHECKSIG OP_VERIFY);
 //! ```
 //!
@@ -73,7 +74,8 @@
 //!
 //! ```rust
 //! # #![feature(proc_macro_hygiene)]
-//! # use bitcoin_script::script;
+//! # use bitcoin_script::{script, define_pushable};
+//! # define_pushable!();
 //! let script = script!(123 -456 999999);
 //! ```
 //!
@@ -83,7 +85,8 @@
 //!
 //! ```rust
 //! # #![feature(proc_macro_hygiene)]
-//! # use bitcoin_script::script;
+//! # use bitcoin_script::{script, define_pushable};
+//! # define_pushable!();
 //! let script = script!(
 //!     0x0102030405060708090a0b0c0d0e0f OP_HASH160
 //! );
@@ -105,7 +108,7 @@
 //! ```rust
 //! # #![feature(proc_macro_hygiene)]
 //! # use bitcoin_script::{script, define_pushable};
-//! define_pushable!();
+//! # define_pushable!();
 //! let bytes = vec![1, 2, 3];
 //!
 //! let script = script! {
@@ -140,7 +143,7 @@ pub fn define_pushable(_: TokenStream) -> TokenStream {
 
         use bitcoin::blockdata::opcodes::{all::*, Opcode};
         use bitcoin::blockdata::script::Builder as BitcoinBuilder;
-        use bitcoin::blockdata::script::{PushBytesBuf, Script};
+        use bitcoin::blockdata::script::{PushBytesBuf, PushBytes, Script};
         use std::convert::TryFrom;
 
         pub struct Builder(pub BitcoinBuilder);
@@ -210,8 +213,8 @@ pub fn define_pushable(_: TokenStream) -> TokenStream {
                 self
             }
 
-            pub fn push_slice(mut self, slice: PushBytesBuf) -> Builder {
-                self.0 = self.0.push_slice(slice);
+            pub fn push_slice<T: AsRef<PushBytes>>(mut self, data: T) -> Builder {
+                self.0 = self.0.push_slice(data);
                 self
             }
 

src/parse.rs

@@ -143,6 +143,7 @@ where
 {
     let mut escape = quote! {
         let mut script_var = vec![];
+        let mut last_opcode = None;
     };
     escape.extend(std::iter::once(token.clone()));
 
@@ -155,16 +156,41 @@ where
                         let next_script = script !{
                             #inner_block
                         };
-                        if script_var.len() > 0 {
-                            if next_script.as_bytes().len() == 0 {
-                                eprintln!("Script can be optimized: Inner block of a for loop iteration is empty.");
-                            } else {
-                                // TODO this could be a data push
-                                let previous_opcode = ::bitcoin::opcodes::Opcode::from(script_var[script_var.len() - 1]);
-                                let opcode = ::bitcoin::opcodes::Opcode::from(next_script.as_bytes()[0]);
-                                pushable::check_optimality(previous_opcode, opcode);
+                        if next_script.as_bytes().len() > 0 {
+                            if let Some(previous_opcode) = last_opcode {
+                                // Check optimality for the next_script first opcode and the previous
+                                // scripts last opcode.
+                                match next_script.instructions_minimal().next() {
+                                    Some(instr_result) => match instr_result {
+                                        Ok(instr) => match instr {
+                                            bitcoin::script::Instruction::PushBytes(push_bytes) => {
+                                                if push_bytes.as_bytes() == [] {
+                                                    pushable::check_optimality(previous_opcode, ::bitcoin::opcodes::all::OP_PUSHBYTES_0)
+                                                }
+                                            },
+                                            bitcoin::script::Instruction::Op(opcode) => pushable::check_optimality(previous_opcode, opcode),
+                                        },
+                                        Err(_) => eprintln!("Script includes non-minimal pushes."),
+                                    },
+                                    None => eprintln!("Script can be optimized: Inner block of a for loop iteration is empty."),
+                                };
                             }
-                        }
+                            // Store last instruction of next_script as Opcode in last_opcode.
+                            match next_script.instructions_minimal().last() {
+                                Some(instr_result) => match instr_result {
+                                    Ok(instr) => match instr {
+                                        bitcoin::script::Instruction::PushBytes(push_bytes) => {
+                                            if push_bytes.as_bytes() == [] {
+                                                last_opcode = Some(::bitcoin::opcodes::all::OP_PUSHBYTES_0);
+                                            }
+                                        },
+                                        bitcoin::script::Instruction::Op(new_last_opcode) => last_opcode = Some(new_last_opcode),
+                                    },
+                                    Err(_) => eprintln!("Script includes non-minimal pushes."),
+                                },
+                                None => (),
+                            };
+                        };
                         script_var.extend_from_slice(next_script.as_bytes());
                     }
                     bitcoin::script::ScriptBuf::from(script_var)