adding user-propagator ability

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/smt/user_propagator.cpp

@@ -0,0 +1,85 @@
+/*++
+Copyright (c) 2020 Microsoft Corporation
+
+Module Name:
+
+    user_propagator.cpp
+
+Abstract:
+
+    User theory propagator plugin.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2020-08-17
+
+--*/
+
+
+#include "smt/user_propagator.h"
+#include "smt/smt_context.h"
+
+using namespace smt;
+
+user_propagator::user_propagator(context& ctx):
+    theory(ctx, ctx.get_manager().mk_family_id("user_propagator")),
+    m_qhead(0)
+{}
+
+unsigned user_propagator::add_expr(expr* e) {
+    return mk_var(ensure_enode(e));
+}
+
+void user_propagator::new_fixed_eh(theory_var v, expr* value, unsigned num_lits, literal const* jlits) {
+    m_id2justification.setx(v, literal_vector(num_lits, jlits), literal_vector());
+    m_fixed_eh(m_user_context, v, value);
+}
+
+void user_propagator::push_scope_eh() {
+    theory::push_scope_eh();
+    m_push_eh(m_user_context);
+    m_prop_lim.push_back(m_prop.size());
+}
+
+void user_propagator::pop_scope_eh(unsigned num_scopes) {
+    m_pop_eh(m_user_context, num_scopes);
+    theory::pop_scope_eh(num_scopes);
+    unsigned old_sz = m_prop_lim.size() - num_scopes;
+    m_prop.shrink(m_prop_lim[old_sz]);
+    m_prop_lim.shrink(old_sz);
+}
+
+bool user_propagator::can_propagate() {
+    return m_qhead < m_prop.size();
+}
+
+void user_propagator::propagate() {
+    unsigned qhead = m_qhead;
+    literal_vector lits;
+    enode_pair_vector eqs;
+    justification* js;
+    while (qhead < m_prop.size() && !ctx.inconsistent()) {
+        auto const& prop = m_prop[qhead];
+        lits.reset();        
+        for (unsigned id : prop.m_ids) 
+            lits.append(m_id2justification[id]);
+        if (m.is_false(prop.m_conseq)) {
+            js = ctx.mk_justification(
+                ext_theory_conflict_justification(
+                    get_id(), ctx.get_region(), lits.size(), lits.c_ptr(), eqs.size(), eqs.c_ptr(), 0, nullptr));
+            ctx.set_conflict(js);
+        }
+        else {
+            literal lit = mk_literal(prop.m_conseq);
+            js = ctx.mk_justification(
+                ext_theory_propagation_justification(
+                    get_id(), ctx.get_region(), lits.size(), lits.c_ptr(), eqs.size(), eqs.c_ptr(), lit));
+            ctx.assign(lit, js);
+        }
+        ++qhead;
+    }
+    ctx.push_trail(value_trail<context, unsigned>(m_qhead));
+    m_qhead = qhead;
+}
+
+