Make clvm_rs a replacement for clvm

src/serde/de_tree.rs

@@ -0,0 +1,327 @@
+use std::convert::TryInto;
+use std::io::{Error, Read, Result, Write};
+
+use sha2::Digest;
+
+use crate::sha2::Sha256;
+
+use super::parse_atom::decode_size_with_offset;
+use super::utils::{copy_exactly, skip_bytes};
+
+const MAX_SINGLE_BYTE: u8 = 0x7f;
+const CONS_BOX_MARKER: u8 = 0xff;
+
+struct ShaWrapper(Sha256);
+
+impl Write for ShaWrapper {
+    fn write(&mut self, blob: &[u8]) -> std::result::Result<usize, Error> {
+        self.0.update(blob);
+        Ok(blob.len())
+    }
+    fn flush(&mut self) -> std::result::Result<(), Error> {
+        Ok(())
+    }
+}
+
+/// This data structure is used with `parse_triples`, which returns a triple of
+/// integer values for each clvm object in a tree.
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum ParsedTriple {
+    Atom {
+        start: u64,
+        end: u64,
+        atom_offset: u32,
+    },
+    Pair {
+        start: u64,
+        end: u64,
+        right_index: u32,
+    },
+}
+
+enum ParseOpRef {
+    ParseObj,
+    SaveCursor(usize),
+    SaveIndex(usize),
+}
+
+fn sha_blobs(blobs: &[&[u8]]) -> [u8; 32] {
+    let mut h = Sha256::new();
+    for blob in blobs {
+        h.update(blob);
+    }
+    h.finalize()
+        .as_slice()
+        .try_into()
+        .expect("wrong slice length")
+}
+
+fn tree_hash_for_byte(b: u8, calculate_tree_hashes: bool) -> Option<[u8; 32]> {
+    if calculate_tree_hashes {
+        Some(sha_blobs(&[&[1, b]]))
+    } else {
+        None
+    }
+}
+
+fn skip_or_sha_bytes<R: Read>(
+    f: &mut R,
+    skip_size: u64,
+    calculate_tree_hashes: bool,
+) -> Result<Option<[u8; 32]>> {
+    if calculate_tree_hashes {
+        let mut h = Sha256::new();
+        h.update([1]);
+        let mut w = ShaWrapper(h);
+        copy_exactly(f, &mut w, skip_size)?;
+        let r: [u8; 32] =
+            w.0.finalize()
+                .as_slice()
+                .try_into()
+                .expect("wrong slice length");
+        Ok(Some(r))
+    } else {
+        skip_bytes(f, skip_size)?;
+        Ok(None)
+    }
+}
+
+/// parse a serialized clvm object tree to an array of `ParsedTriple` objects
+
+/// This alternative mechanism of deserialization generates an array of
+/// references to each clvm object. A reference contains three values:
+/// a start offset within the blob, an end offset, and a third value that
+/// is either: an atom offset (relative to the start offset) where the atom
+/// data starts (and continues to the end offset); or an index in the array
+/// corresponding to the "right" element of the pair (in which case, the
+/// "left" element corresponds to the current index + 1).
+///
+/// Since these values are offsets into the original buffer, that buffer needs
+/// to be kept around to get the original atoms.
+
+type ParsedTriplesOutput = (Vec<ParsedTriple>, Option<Vec<[u8; 32]>>);
+
+pub fn parse_triples<R: Read>(
+    f: &mut R,
+    calculate_tree_hashes: bool,
+) -> Result<ParsedTriplesOutput> {
+    let mut r = Vec::new();
+    let mut tree_hashes = Vec::new();
+    let mut op_stack = vec![ParseOpRef::ParseObj];
+    let mut cursor: u64 = 0;
+    loop {
+        match op_stack.pop() {
+            None => {
+                break;
+            }
+            Some(op) => match op {
+                ParseOpRef::ParseObj => {
+                    let mut b: [u8; 1] = [0];
+                    f.read_exact(&mut b)?;
+                    let start = cursor;
+                    cursor += 1;
+                    let b = b[0];
+                    if b == CONS_BOX_MARKER {
+                        let index = r.len();
+                        let new_obj = ParsedTriple::Pair {
+                            start,
+                            end: 0,
+                            right_index: 0,
+                        };
+                        r.push(new_obj);
+                        if calculate_tree_hashes {
+                            tree_hashes.push([0; 32])
+                        }
+                        op_stack.push(ParseOpRef::SaveCursor(index));
+                        op_stack.push(ParseOpRef::ParseObj);
+                        op_stack.push(ParseOpRef::SaveIndex(index));
+                        op_stack.push(ParseOpRef::ParseObj);
+                    } else {
+                        let (start, end, atom_offset, tree_hash) = {
+                            if b <= MAX_SINGLE_BYTE {
+                                (
+                                    start,
+                                    start + 1,
+                                    0,
+                                    tree_hash_for_byte(b, calculate_tree_hashes),
+                                )
+                            } else {
+                                let (atom_offset, atom_size) = decode_size_with_offset(f, b)?;
+                                let end = start + (atom_offset as u64) + atom_size;
+                                let h = skip_or_sha_bytes(f, atom_size, calculate_tree_hashes)?;
+                                (start, end, atom_offset as u32, h)
+                            }
+                        };
+                        if calculate_tree_hashes {
+                            tree_hashes.push(tree_hash.expect("failed unwrap"))
+                        }
+                        let new_obj = ParsedTriple::Atom {
+                            start,
+                            end,
+                            atom_offset,
+                        };
+                        cursor = end;
+                        r.push(new_obj);
+                    }
+                }
+                ParseOpRef::SaveCursor(index) => {
+                    if let ParsedTriple::Pair {
+                        start,
+                        end: _,
+                        right_index,
+                    } = r[index]
+                    {
+                        if calculate_tree_hashes {
+                            let h = sha_blobs(&[
+                                &[2],
+                                &tree_hashes[index + 1],
+                                &tree_hashes[right_index as usize],
+                            ]);
+                            tree_hashes[index] = h;
+                        }
+                        r[index] = ParsedTriple::Pair {
+                            start,
+                            end: cursor,
+                            right_index,
+                        };
+                    }
+                }
+                ParseOpRef::SaveIndex(index) => {
+                    if let ParsedTriple::Pair {
+                        start,
+                        end,
+                        right_index: _,
+                    } = r[index]
+                    {
+                        r[index] = ParsedTriple::Pair {
+                            start,
+                            end,
+                            right_index: r.len() as u32,
+                        };
+                    }
+                }
+            },
+        }
+    }
+    Ok((
+        r,
+        if calculate_tree_hashes {
+            Some(tree_hashes)
+        } else {
+            None
+        },
+    ))
+}
+
+#[cfg(test)]
+use std::io::Cursor;
+
+#[cfg(test)]
+use hex::FromHex;
+
+#[cfg(test)]
+fn check_parse_tree(h: &str, expected: Vec<ParsedTriple>, expected_sha_tree_hex: &str) -> () {
+    let b = Vec::from_hex(h).unwrap();
+    println!("{:?}", b);
+    let mut f = Cursor::new(b);
+    let (p, tree_hash) = parse_triples(&mut f, false).unwrap();
+    assert_eq!(p, expected);
+    assert_eq!(tree_hash, None);
+
+    let b = Vec::from_hex(h).unwrap();
+    let mut f = Cursor::new(b);
+    let (p, tree_hash) = parse_triples(&mut f, true).unwrap();
+    assert_eq!(p, expected);
+
+    let est = Vec::from_hex(expected_sha_tree_hex).unwrap();
+    assert_eq!(tree_hash.unwrap()[0].to_vec(), est);
+}
+
+#[test]
+fn test_parse_tree() {
+    check_parse_tree(
+        "80",
+        vec![ParsedTriple::Atom {
+            start: 0,
+            end: 1,
+            atom_offset: 1,
+        }],
+        "4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a",
+    );
+
+    check_parse_tree(
+        "ff648200c8",
+        vec![
+            ParsedTriple::Pair {
+                start: 0,
+                end: 5,
+                right_index: 2,
+            },
+            ParsedTriple::Atom {
+                start: 1,
+                end: 2,
+                atom_offset: 0,
+            },
+            ParsedTriple::Atom {
+                start: 2,
+                end: 5,
+                atom_offset: 1,
+            },
+        ],
+        "247f7d3f63b346ea93ca47f571cd0f4455392348b888a4286072bef0ac6069b5",
+    );
+
+    check_parse_tree(
+        "ff83666f6fff83626172ff8362617a80", // `(foo bar baz)`
+        vec![
+            ParsedTriple::Pair {
+                start: 0,
+                end: 16,
+                right_index: 2,
+            },
+            ParsedTriple::Atom {
+                start: 1,
+                end: 5,
+                atom_offset: 1,
+            },
+            ParsedTriple::Pair {
+                start: 5,
+                end: 16,
+                right_index: 4,
+            },
+            ParsedTriple::Atom {
+                start: 6,
+                end: 10,
+                atom_offset: 1,
+            },
+            ParsedTriple::Pair {
+                start: 10,
+                end: 16,
+                right_index: 6,
+            },
+            ParsedTriple::Atom {
+                start: 11,
+                end: 15,
+                atom_offset: 1,
+            },
+            ParsedTriple::Atom {
+                start: 15,
+                end: 16,
+                atom_offset: 1,
+            },
+        ],
+        "47f30bf9935e25e4262023124fb5e986d755b9ed65a28ac78925c933bfd57dbd",
+    );
+
+    let s = "c0a0".to_owned() + &hex::encode([0x31u8; 160]);
+    check_parse_tree(
+        &s,
+        vec![ParsedTriple::Atom {
+            start: 0,
+            end: 162,
+            atom_offset: 2,
+        }],
+        "d1c109981a9c5a3bbe2d98795a186a0f057dc9a3a7f5e1eb4dfb63a1636efa2d",
+    );
+}

src/serde/mod.rs

@@ -1,20 +1,23 @@
 mod bytes32;
 mod de;
 mod de_br;
+mod de_tree;
 mod errors;
 mod object_cache;
 mod parse_atom;
 mod read_cache_lookup;
 mod ser;
 mod ser_br;
 mod tools;
+mod utils;
 mod write_atom;
 
 #[cfg(test)]
 mod test;
 
 pub use de::node_from_bytes;
 pub use de_br::node_from_bytes_backrefs;
+pub use de_tree::{parse_triples, ParsedTriple};
 pub use ser::node_to_bytes;
 pub use ser_br::node_to_bytes_backrefs;
-pub use tools::{serialized_length_from_bytes, tree_hash_from_stream};
+pub use tools::{parse_through_clvm_object, serialized_length_from_bytes, tree_hash_from_stream};