From 1ddaa66eae67b102f5e37d212d366a5dcad4aa26 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Wed, 28 Aug 2019 16:23:03 -0700
Subject: Miniscript: type system, script creation, text notation, tests

More information about Miniscript can be found at https://bitcoin.sipa.be/miniscript/ (the
website source is hosted at https://github.com/sipa/miniscript/).
This commit defines all fragments, their composition, parsing from
string representation and conversion to Script.

Co-Authored-By: Antoine Poinsot <darosior@protonmail.com>
Co-Authored-By: Sanket Kanjalkar <sanket1729@gmail.com>
Co-Authored-By: Samuel Dobson <dobsonsa68@gmail.com>
---
 src/script/miniscript.cpp | 295 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 295 insertions(+)
 create mode 100644 src/script/miniscript.cpp

(limited to 'src/script/miniscript.cpp')

diff --git a/src/script/miniscript.cpp b/src/script/miniscript.cpp
new file mode 100644
index 0000000000..8074be6cde
--- /dev/null
+++ b/src/script/miniscript.cpp
@@ -0,0 +1,295 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <string>
+#include <vector>
+#include <script/script.h>
+#include <script/miniscript.h>
+
+#include <assert.h>
+
+namespace miniscript {
+namespace internal {
+
+Type SanitizeType(Type e) {
+    int num_types = (e << "K"_mst) + (e << "V"_mst) + (e << "B"_mst) + (e << "W"_mst);
+    if (num_types == 0) return ""_mst; // No valid type, don't care about the rest
+    assert(num_types == 1); // K, V, B, W all conflict with each other
+    bool ok = // Work around a GCC 4.8 bug that breaks user-defined literals in macro calls.
+        (!(e << "z"_mst) || !(e << "o"_mst)) && // z conflicts with o
+        (!(e << "n"_mst) || !(e << "z"_mst)) && // n conflicts with z
+        (!(e << "n"_mst) || !(e << "W"_mst)) && // n conflicts with W
+        (!(e << "V"_mst) || !(e << "d"_mst)) && // V conflicts with d
+        (!(e << "K"_mst) ||  (e << "u"_mst)) && // K implies u
+        (!(e << "V"_mst) || !(e << "u"_mst)) && // V conflicts with u
+        (!(e << "e"_mst) || !(e << "f"_mst)) && // e conflicts with f
+        (!(e << "e"_mst) ||  (e << "d"_mst)) && // e implies d
+        (!(e << "V"_mst) || !(e << "e"_mst)) && // V conflicts with e
+        (!(e << "d"_mst) || !(e << "f"_mst)) && // d conflicts with f
+        (!(e << "V"_mst) ||  (e << "f"_mst)) && // V implies f
+        (!(e << "K"_mst) ||  (e << "s"_mst)) && // K implies s
+        (!(e << "z"_mst) ||  (e << "m"_mst)); // z implies m
+    assert(ok);
+    return e;
+}
+
+Type ComputeType(Fragment nodetype, Type x, Type y, Type z, const std::vector<Type>& sub_types, uint32_t k, size_t data_size, size_t n_subs, size_t n_keys) {
+    // Sanity check on data
+    if (nodetype == Fragment::SHA256 || nodetype == Fragment::HASH256) {
+        assert(data_size == 32);
+    } else if (nodetype == Fragment::RIPEMD160 || nodetype == Fragment::HASH160) {
+        assert(data_size == 20);
+    } else {
+        assert(data_size == 0);
+    }
+    // Sanity check on k
+    if (nodetype == Fragment::OLDER || nodetype == Fragment::AFTER) {
+        assert(k >= 1 && k < 0x80000000UL);
+    } else if (nodetype == Fragment::MULTI) {
+        assert(k >= 1 && k <= n_keys);
+    } else if (nodetype == Fragment::THRESH) {
+        assert(k >= 1 && k <= n_subs);
+    } else {
+        assert(k == 0);
+    }
+    // Sanity check on subs
+    if (nodetype == Fragment::AND_V || nodetype == Fragment::AND_B || nodetype == Fragment::OR_B ||
+        nodetype == Fragment::OR_C || nodetype == Fragment::OR_I || nodetype == Fragment::OR_D) {
+        assert(n_subs == 2);
+    } else if (nodetype == Fragment::ANDOR) {
+        assert(n_subs == 3);
+    } else if (nodetype == Fragment::WRAP_A || nodetype == Fragment::WRAP_S || nodetype == Fragment::WRAP_C ||
+               nodetype == Fragment::WRAP_D || nodetype == Fragment::WRAP_V || nodetype == Fragment::WRAP_J ||
+               nodetype == Fragment::WRAP_N) {
+        assert(n_subs == 1);
+    } else if (nodetype != Fragment::THRESH) {
+        assert(n_subs == 0);
+    }
+    // Sanity check on keys
+    if (nodetype == Fragment::PK_K || nodetype == Fragment::PK_H) {
+        assert(n_keys == 1);
+    } else if (nodetype == Fragment::MULTI) {
+        assert(n_keys >= 1 && n_keys <= 20);
+    } else {
+        assert(n_keys == 0);
+    }
+
+    // Below is the per-nodetype logic for computing the expression types.
+    // It heavily relies on Type's << operator (where "X << a_mst" means
+    // "X has all properties listed in a").
+    switch (nodetype) {
+        case Fragment::PK_K: return "Konudemsxk"_mst;
+        case Fragment::PK_H: return "Knudemsxk"_mst;
+        case Fragment::OLDER: return
+            "g"_mst.If(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) |
+            "h"_mst.If(!(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)) |
+            "Bzfmxk"_mst;
+        case Fragment::AFTER: return
+            "i"_mst.If(k >= LOCKTIME_THRESHOLD) |
+            "j"_mst.If(k < LOCKTIME_THRESHOLD) |
+            "Bzfmxk"_mst;
+        case Fragment::SHA256: return "Bonudmk"_mst;
+        case Fragment::RIPEMD160: return "Bonudmk"_mst;
+        case Fragment::HASH256: return "Bonudmk"_mst;
+        case Fragment::HASH160: return "Bonudmk"_mst;
+        case Fragment::JUST_1: return "Bzufmxk"_mst;
+        case Fragment::JUST_0: return "Bzudemsxk"_mst;
+        case Fragment::WRAP_A: return
+            "W"_mst.If(x << "B"_mst) | // W=B_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "udfems"_mst) | // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
+            "x"_mst; // x
+        case Fragment::WRAP_S: return
+            "W"_mst.If(x << "Bo"_mst) | // W=B_x*o_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "udfemsx"_mst); // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x, x=x_x
+        case Fragment::WRAP_C: return
+            "B"_mst.If(x << "K"_mst) | // B=K_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "ondfem"_mst) | // o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x
+            "us"_mst; // u, s
+        case Fragment::WRAP_D: return
+            "B"_mst.If(x << "Vz"_mst) | // B=V_x*z_x
+            "o"_mst.If(x << "z"_mst) | // o=z_x
+            "e"_mst.If(x << "f"_mst) | // e=f_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "ms"_mst) | // m=m_x, s=s_x
+            "nudx"_mst; // n, u, d, x
+        case Fragment::WRAP_V: return
+            "V"_mst.If(x << "B"_mst) | // V=B_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "zonms"_mst) | // z=z_x, o=o_x, n=n_x, m=m_x, s=s_x
+            "fx"_mst; // f, x
+        case Fragment::WRAP_J: return
+            "B"_mst.If(x << "Bn"_mst) | // B=B_x*n_x
+            "e"_mst.If(x << "f"_mst) | // e=f_x
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "oums"_mst) | // o=o_x, u=u_x, m=m_x, s=s_x
+            "ndx"_mst; // n, d, x
+        case Fragment::WRAP_N: return
+            (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
+            (x & "Bzondfems"_mst) | // B=B_x, z=z_x, o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
+            "ux"_mst; // u, x
+        case Fragment::AND_V: return
+            (y & "KVB"_mst).If(x << "V"_mst) | // B=V_x*B_y, V=V_x*V_y, K=V_x*K_y
+            (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
+            ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
+            (x & y & "dmz"_mst) | // d=d_x*d_y, m=m_x*m_y, z=z_x*z_y
+            ((x | y) & "s"_mst) | // s=s_x+s_y
+            "f"_mst.If((y << "f"_mst) || (x << "s"_mst)) | // f=f_y+s_x
+            (y & "ux"_mst) | // u=u_y, x=x_y
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            "k"_mst.If(((x & y) << "k"_mst) &&
+                !(((x << "g"_mst) && (y << "h"_mst)) ||
+                ((x << "h"_mst) && (y << "g"_mst)) ||
+                ((x << "i"_mst) && (y << "j"_mst)) ||
+                ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
+        case Fragment::AND_B: return
+            (x & "B"_mst).If(y << "W"_mst) | // B=B_x*W_y
+            ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
+            (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
+            (x & y & "e"_mst).If((x & y) << "s"_mst) | // e=e_x*e_y*s_x*s_y
+            (x & y & "dzm"_mst) | // d=d_x*d_y, z=z_x*z_y, m=m_x*m_y
+            "f"_mst.If(((x & y) << "f"_mst) || (x << "sf"_mst) || (y << "sf"_mst)) | // f=f_x*f_y + f_x*s_x + f_y*s_y
+            ((x | y) & "s"_mst) | // s=s_x+s_y
+            "ux"_mst | // u, x
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            "k"_mst.If(((x & y) << "k"_mst) &&
+                !(((x << "g"_mst) && (y << "h"_mst)) ||
+                ((x << "h"_mst) && (y << "g"_mst)) ||
+                ((x << "i"_mst) && (y << "j"_mst)) ||
+                ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
+        case Fragment::OR_B: return
+            "B"_mst.If(x << "Bd"_mst && y << "Wd"_mst) | // B=B_x*d_x*W_x*d_y
+            ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
+            (x & y & "m"_mst).If((x | y) << "s"_mst && (x & y) << "e"_mst) | // m=m_x*m_y*e_x*e_y*(s_x+s_y)
+            (x & y & "zse"_mst) | // z=z_x*z_y, s=s_x*s_y, e=e_x*e_y
+            "dux"_mst | // d, u, x
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            (x & y & "k"_mst); // k=k_x*k_y
+        case Fragment::OR_D: return
+            (y & "B"_mst).If(x << "Bdu"_mst) | // B=B_y*B_x*d_x*u_x
+            (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
+            (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
+            (x & y & "zes"_mst) | // z=z_x*z_y, e=e_x*e_y, s=s_x*s_y
+            (y & "ufd"_mst) | // u=u_y, f=f_y, d=d_y
+            "x"_mst | // x
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            (x & y & "k"_mst); // k=k_x*k_y
+        case Fragment::OR_C: return
+            (y & "V"_mst).If(x << "Bdu"_mst) | // V=V_y*B_x*u_x*d_x
+            (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
+            (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
+            (x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y
+            "fx"_mst | // f, x
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            (x & y & "k"_mst); // k=k_x*k_y
+        case Fragment::OR_I: return
+            (x & y & "VBKufs"_mst) | // V=V_x*V_y, B=B_x*B_y, K=K_x*K_y, u=u_x*u_y, f=f_x*f_y, s=s_x*s_y
+            "o"_mst.If((x & y) << "z"_mst) | // o=z_x*z_y
+            ((x | y) & "e"_mst).If((x | y) << "f"_mst) | // e=e_x*f_y+f_x*e_y
+            (x & y & "m"_mst).If((x | y) << "s"_mst) | // m=m_x*m_y*(s_x+s_y)
+            ((x | y) & "d"_mst) | // d=d_x+d_y
+            "x"_mst | // x
+            ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
+            (x & y & "k"_mst); // k=k_x*k_y
+        case Fragment::ANDOR: return
+            (y & z & "BKV"_mst).If(x << "Bdu"_mst) | // B=B_x*d_x*u_x*B_y*B_z, K=B_x*d_x*u_x*K_y*K_z, V=B_x*d_x*u_x*V_y*V_z
+            (x & y & z & "z"_mst) | // z=z_x*z_y*z_z
+            ((x | (y & z)) & "o"_mst).If((x | (y & z)) << "z"_mst) | // o=o_x*z_y*z_z+z_x*o_y*o_z
+            (y & z & "u"_mst) | // u=u_y*u_z
+            (z & "f"_mst).If((x << "s"_mst) || (y << "f"_mst)) | // f=(s_x+f_y)*f_z
+            (z & "d"_mst) | // d=d_z
+            (x & z & "e"_mst).If(x << "s"_mst || y << "f"_mst) | // e=e_x*e_z*(s_x+f_y)
+            (x & y & z & "m"_mst).If(x << "e"_mst && (x | y | z) << "s"_mst) | // m=m_x*m_y*m_z*e_x*(s_x+s_y+s_z)
+            (z & (x | y) & "s"_mst) | // s=s_z*(s_x+s_y)
+            "x"_mst | // x
+            ((x | y | z) & "ghij"_mst) | // g=g_x+g_y+g_z, h=h_x+h_y+h_z, i=i_x+i_y+i_z, j=j_x+j_y_j_z
+            "k"_mst.If(((x & y & z) << "k"_mst) &&
+                !(((x << "g"_mst) && (y << "h"_mst)) ||
+                ((x << "h"_mst) && (y << "g"_mst)) ||
+                ((x << "i"_mst) && (y << "j"_mst)) ||
+                ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*k_z* !(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
+        case Fragment::MULTI: return "Bnudemsk"_mst;
+        case Fragment::THRESH: {
+            bool all_e = true;
+            bool all_m = true;
+            uint32_t args = 0;
+            uint32_t num_s = 0;
+            Type acc_tl = "k"_mst;
+            for (size_t i = 0; i < sub_types.size(); ++i) {
+                Type t = sub_types[i];
+                if (!(t << (i ? "Wdu"_mst : "Bdu"_mst))) return ""_mst; // Require Bdu, Wdu, Wdu, ...
+                if (!(t << "e"_mst)) all_e = false;
+                if (!(t << "m"_mst)) all_m = false;
+                if (t << "s"_mst) num_s += 1;
+                args += (t << "z"_mst) ? 0 : (t << "o"_mst) ? 1 : 2;
+                acc_tl = ((acc_tl | t) & "ghij"_mst) |
+                    // Thresh contains a combination of timelocks if it has threshold > 1 and
+                    // it contains two different children that have different types of timelocks
+                    // Note how if any of the children don't have "k", the parent also does not have "k"
+                    "k"_mst.If(((acc_tl & t) << "k"_mst) && ((k <= 1) ||
+                        ((k > 1) && !(((acc_tl << "g"_mst) && (t << "h"_mst)) ||
+                        ((acc_tl << "h"_mst) && (t << "g"_mst)) ||
+                        ((acc_tl << "i"_mst) && (t << "j"_mst)) ||
+                        ((acc_tl << "j"_mst) && (t << "i"_mst))))));
+            }
+            return "Bdu"_mst |
+                   "z"_mst.If(args == 0) | // z=all z
+                   "o"_mst.If(args == 1) | // o=all z except one o
+                   "e"_mst.If(all_e && num_s == n_subs) | // e=all e and all s
+                   "m"_mst.If(all_e && all_m && num_s >= n_subs - k) | // m=all e, >=(n-k) s
+                   "s"_mst.If(num_s >= n_subs - k + 1) |  // s= >=(n-k+1) s
+                   acc_tl; // timelock info
+            }
+    }
+    assert(false);
+    return ""_mst;
+}
+
+size_t ComputeScriptLen(Fragment nodetype, Type sub0typ, size_t subsize, uint32_t k, size_t n_subs, size_t n_keys) {
+    switch (nodetype) {
+        case Fragment::JUST_1:
+        case Fragment::JUST_0: return 1;
+        case Fragment::PK_K: return 34;
+        case Fragment::PK_H: return 3 + 21;
+        case Fragment::OLDER:
+        case Fragment::AFTER: return 1 + BuildScript(k).size();
+        case Fragment::HASH256:
+        case Fragment::SHA256: return 4 + 2 + 33;
+        case Fragment::HASH160:
+        case Fragment::RIPEMD160: return 4 + 2 + 21;
+        case Fragment::MULTI: return 3 + (n_keys > 16) + (k > 16) + 34 * n_keys;
+        case Fragment::AND_V: return subsize;
+        case Fragment::WRAP_V: return subsize + (sub0typ << "x"_mst);
+        case Fragment::WRAP_S:
+        case Fragment::WRAP_C:
+        case Fragment::WRAP_N:
+        case Fragment::AND_B:
+        case Fragment::OR_B: return subsize + 1;
+        case Fragment::WRAP_A:
+        case Fragment::OR_C: return subsize + 2;
+        case Fragment::WRAP_D:
+        case Fragment::OR_D:
+        case Fragment::OR_I:
+        case Fragment::ANDOR: return subsize + 3;
+        case Fragment::WRAP_J: return subsize + 4;
+        case Fragment::THRESH: return subsize + n_subs + BuildScript(k).size();
+    }
+    assert(false);
+    return 0;
+}
+
+int FindNextChar(Span<const char> sp, const char m)
+{
+    for (int i = 0; i < (int)sp.size(); ++i) {
+        if (sp[i] == m) return i;
+        // We only search within the current parentheses
+        if (sp[i] == ')') break;
+    }
+    return -1;
+}
+
+} // namespace internal
+} // namespace miniscript
-- 
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