grammar.cc

#include <typeinfo>
#include <numeric>
#include <algorithm>
#include <stdexcept>
#include <cassert>

#include "random.hh"
#include "relmodel.hh"
#include "grammar.hh"
#include "schema.hh"
#include "impedance.hh"

using namespace std;

shared_ptr<table_ref> table_ref::factory(prod *p) {
  try {
    if (p->level < 3 + d6()) {
      if (d6() > 3 && p->level < d6())
	return make_shared<table_subquery>(p);
      if (d6() > 3)
	return make_shared<joined_table>(p);
    }
    if (d6() > 3)
      return make_shared<table_or_query_name>(p);
    else
      return make_shared<table_sample>(p);
  } catch (runtime_error &e) {
    p->retry();
  }
  return factory(p);
}

table_or_query_name::table_or_query_name(prod *p) : table_ref(p) {
  t = random_pick(scope->tables);
  refs.push_back(make_shared<aliased_relation>(scope->stmt_uid("ref"), t));
}

void table_or_query_name::out(std::ostream &out) {
  out << t->ident() << " as " << refs[0]->ident();
}

target_table::target_table(prod *p, table *victim) : table_ref(p)
{
  while (! victim
	 || victim->schema == "pg_catalog"
	 || !victim->is_base_table
	 || !victim->columns().size()) {
    struct named_relation *pick = random_pick(scope->tables);
    victim = dynamic_cast<table *>(pick);
    retry();
  }
  victim_ = victim;
  refs.push_back(make_shared<aliased_relation>(scope->stmt_uid("target"), victim));
}

void target_table::out(std::ostream &out) {
  out << victim_->ident() << " as " << refs[0]->ident();
}

table_sample::table_sample(prod *p) : table_ref(p) {
  match();
  retry_limit = 1000; /* retries are cheap here */
  do {
    auto pick = random_pick(scope->schema->base_tables);
    t = dynamic_cast<struct table*>(pick);
    retry();
  } while (!t || !t->is_base_table);
  
  refs.push_back(make_shared<aliased_relation>(scope->stmt_uid("sample"), t));
  percent = 0.1 * d100();
  method = (d6() > 2) ? "system" : "bernoulli";
}

void table_sample::out(std::ostream &out) {
  out << t->ident() <<
    " as " << refs[0]->ident() <<
    " tablesample " << method <<
    " (" << percent << ") ";
}

table_subquery::table_subquery(prod *p, bool lateral)
  : table_ref(p), is_lateral(lateral) {
  query = make_shared<query_spec>(this, scope, lateral);
  string alias = scope->stmt_uid("subq");
  relation *aliased_rel = &query->select_list->derived_table;
  refs.push_back(make_shared<aliased_relation>(alias, aliased_rel));
}

table_subquery::~table_subquery() { }

void table_subquery::accept(prod_visitor *v) {
  query->accept(v);
  v->visit(this);
}

shared_ptr<join_cond> join_cond::factory(prod *p, table_ref &lhs, table_ref &rhs)
{
     try {
	  if (d6() < 6)
	       return make_shared<expr_join_cond>(p, lhs, rhs);
	  else
	       return make_shared<simple_join_cond>(p, lhs, rhs);
     } catch (runtime_error &e) {
	  p->retry();
     }
     return factory(p, lhs, rhs);
}

simple_join_cond::simple_join_cond(prod *p, table_ref &lhs, table_ref &rhs)
     : join_cond(p, lhs, rhs)
{
retry:
  named_relation *left_rel = &*random_pick(lhs.refs);
  
  if (!left_rel->columns().size())
    { retry(); goto retry; }

  named_relation *right_rel = &*random_pick(rhs.refs);

  column &c1 = random_pick(left_rel->columns());

  for (auto c2 : right_rel->columns()) {
    if (c1.type == c2.type) {
      condition +=
	left_rel->ident() + "." + c1.name + " = " + right_rel->ident() + "." + c2.name + " ";
      break;
    }
  }
  if (condition == "") {
    retry(); goto retry;
  }
}

void simple_join_cond::out(std::ostream &out) {
     out << condition;
}

expr_join_cond::expr_join_cond(prod *p, table_ref &lhs, table_ref &rhs)
     : join_cond(p, lhs, rhs), joinscope(p->scope)
{
     scope = &joinscope;
     for (auto ref: lhs.refs)
	  joinscope.refs.push_back(&*ref);
     for (auto ref: rhs.refs)
	  joinscope.refs.push_back(&*ref);
     search = bool_expr::factory(this);
}

void expr_join_cond::out(std::ostream &out) {
     out << *search;
}

joined_table::joined_table(prod *p) : table_ref(p) {
  lhs = table_ref::factory(this);
  rhs = table_ref::factory(this);

  condition = join_cond::factory(this, *lhs, *rhs);

  if (d6()<4) {
    type = "inner";
  } else if (d6()<4) {
    type = "left";
  } else {
    type = "right";
  }

  for (auto ref: lhs->refs)
    refs.push_back(ref);
  for (auto ref: rhs->refs)
    refs.push_back(ref);
}

void joined_table::out(std::ostream &out) {
  out << *lhs;
  indent(out);
  out << type << " join " << *rhs;
  indent(out);
  out << "on (" << *condition << ")";
}

void table_subquery::out(std::ostream &out) {
  if (is_lateral)
    out << "lateral ";
  out << "(" << *query << ") as " << refs[0]->ident();
}

void from_clause::out(std::ostream &out) {
  if (! reflist.size())
    return;
  out << "from ";

  for (auto r = reflist.begin(); r < reflist.end(); r++) {
    indent(out);
    out << **r;
    if (r + 1 != reflist.end())
      out << ",";
  }
}

from_clause::from_clause(prod *p) : prod(p) {
  reflist.push_back(table_ref::factory(this));
  for (auto r : reflist.back()->refs)
    scope->refs.push_back(&*r);

  while (d6() > 5) {
    // add a lateral subquery
    if (!impedance::matched(typeid(lateral_subquery)))
      break;
    reflist.push_back(make_shared<lateral_subquery>(this));
    for (auto r : reflist.back()->refs)
      scope->refs.push_back(&*r);
  }
}

select_list::select_list(prod *p) : prod(p)
{
  do {
    shared_ptr<value_expr> e = value_expr::factory(this);
    value_exprs.push_back(e);
    ostringstream name;
    name << "c" << columns++;
    sqltype *t=e->type;
    assert(t);
    derived_table.columns().push_back(column(name.str(), t));
  } while (d6() > 1);
}

void select_list::out(std::ostream &out)
{
  int i = 0;
  for (auto expr = value_exprs.begin(); expr != value_exprs.end(); expr++) {
    indent(out);
    out << **expr << " as " << derived_table.columns()[i].name;
    i++;
    if (expr+1 != value_exprs.end())
      out << ", ";
  }
}

void query_spec::out(std::ostream &out) {
  out << "select " << set_quantifier << " "
      << *select_list;
  indent(out);
  out << *from_clause;
  indent(out);
  out << "where ";
  out << *search;
  if (limit_clause.length()) {
    indent(out);
    out << limit_clause;
  }
}

struct for_update_verify : prod_visitor {
  virtual void visit(prod *p) {
    if (dynamic_cast<window_function*>(p))
      throw("window function");
    joined_table* join = dynamic_cast<joined_table*>(p);
    if (join && join->type != "inner")
      throw("outer join");
    query_spec* subquery = dynamic_cast<query_spec*>(p);
    if (subquery)
      subquery->set_quantifier = "";
    table_or_query_name* tab = dynamic_cast<table_or_query_name*>(p);
    if (tab) {
      table *actual_table = dynamic_cast<table*>(tab->t);
      if (actual_table && !actual_table->is_insertable)
	throw("read only");
      if (actual_table->name.find("pg_"))
	throw("catalog");
    }
    table_sample* sample = dynamic_cast<table_sample*>(p);
    if (sample) {
      table *actual_table = dynamic_cast<table*>(sample->t);
      if (actual_table && !actual_table->is_insertable)
	throw("read only");
      if (actual_table->name.find("pg_"))
	throw("catalog");
    }
  } ;
};


select_for_update::select_for_update(prod *p, struct scope *s, bool lateral)
  : query_spec(p,s,lateral)
{
  static const char *modes[] = {
    "update",
    "share",
    "no key update",
    "key share",
  };

  try {
    for_update_verify v1;
    this->accept(&v1);

  } catch (const char* reason) {
    lockmode = 0;
    return;
  }
  lockmode = modes[d6()%(sizeof(modes)/sizeof(*modes))];
  set_quantifier = ""; // disallow distinct
}

void select_for_update::out(std::ostream &out) {
  query_spec::out(out);
  if (lockmode) {
    indent(out);
    out << " for " << lockmode;
  }
}

query_spec::query_spec(prod *p, struct scope *s, bool lateral) :
  prod(p), myscope(s)
{
  scope = &myscope;
  scope->tables = s->tables;

  if (lateral)
    scope->refs = s->refs;
  
  from_clause = make_shared<struct from_clause>(this);
  select_list = make_shared<struct select_list>(this);
  
  set_quantifier = (d100() == 1) ? "distinct" : "";

  search = bool_expr::factory(this);

  if (d6() > 2) {
    ostringstream cons;
    cons << "limit " << d100() + d100();
    limit_clause = cons.str();
  }
}

long prepare_stmt::seq;

void modifying_stmt::pick_victim()
{
  do {
      struct named_relation *pick = random_pick(scope->tables);
      victim = dynamic_cast<struct table*>(pick);
      retry();
    } while (! victim
	   || victim->schema == "pg_catalog"
	   || !victim->is_base_table
	   || !victim->columns().size());
}

modifying_stmt::modifying_stmt(prod *p, struct scope *s, table *victim)
  : prod(p), myscope(s)
{
  scope = &myscope;
  scope->tables = s->tables;

  if (!victim)
    pick_victim();
}


delete_stmt::delete_stmt(prod *p, struct scope *s, table *v)
  : modifying_stmt(p,s,v) {
  scope->refs.push_back(victim);
  search = bool_expr::factory(this);
}

delete_returning::delete_returning(prod *p, struct scope *s, table *victim)
  : delete_stmt(p, s, victim) {
  match();
  select_list = make_shared<struct select_list>(this);
}

insert_stmt::insert_stmt(prod *p, struct scope *s, table *v)
  : modifying_stmt(p, s, v)
{
  match();

  for (auto col : victim->columns()) {
    auto expr = value_expr::factory(this, col.type);
    assert(expr->type == col.type);
    value_exprs.push_back(expr);
  }
}

void insert_stmt::out(std::ostream &out)
{
  out << "insert into " << victim->ident() << " ";

  if (!value_exprs.size()) {
    out << "default values";
    return;
  }

  out << "values (";
  
  for (auto expr = value_exprs.begin();
       expr != value_exprs.end();
       expr++) {
    indent(out);
    out << **expr;
    if (expr+1 != value_exprs.end())
      out << ", ";
  }
  out << ")";
}

set_list::set_list(prod *p, table *target) : prod(p)
{
  do {
    for (auto col : target->columns()) {
      if (d6() < 4)
	continue;
      auto expr = value_expr::factory(this, col.type);
      value_exprs.push_back(expr);
      names.push_back(col.name);
    }
  } while (!names.size());
}

void set_list::out(std::ostream &out)
{
  assert(names.size());
  out << " set ";
  for (size_t i = 0; i < names.size(); i++) {
    indent(out);
    out << names[i] << " = " << *value_exprs[i];
    if (i+1 != names.size())
      out << ", ";
  }
}

update_stmt::update_stmt(prod *p, struct scope *s, table *v)
  : modifying_stmt(p, s, v) {
  scope->refs.push_back(victim);
  search = bool_expr::factory(this);
  set_list = make_shared<struct set_list>(this, victim);
}

void update_stmt::out(std::ostream &out)
{
  out << "update " << victim->ident() << *set_list;
}

update_returning::update_returning(prod *p, struct scope *s, table *v)
  : update_stmt(p, s, v) {
  match();

  select_list = make_shared<struct select_list>(this);
}


upsert_stmt::upsert_stmt(prod *p, struct scope *s, table *v)
  : insert_stmt(p,s,v)
{
  match();

  if (!victim->constraints.size())
    fail("need table w/ constraint for upsert");
    
  set_list = std::make_shared<struct set_list>(this, victim);
  search = bool_expr::factory(this);
  constraint = random_pick(victim->constraints);
}

shared_ptr<prod> statement_factory(struct scope *s)
{
  try {
    s->new_stmt();
    if (d42() == 1)
      return make_shared<merge_stmt>((struct prod *)0, s);
    if (d42() == 1)
      return make_shared<insert_stmt>((struct prod *)0, s);
    else if (d42() == 1)
      return make_shared<delete_returning>((struct prod *)0, s);
    else if (d42() == 1) {
      return make_shared<upsert_stmt>((struct prod *)0, s);
    } else if (d42() == 1)
      return make_shared<update_returning>((struct prod *)0, s);
    else if (d6() > 4)
      return make_shared<select_for_update>((struct prod *)0, s);
    else if (d6() > 5)
      return make_shared<common_table_expression>((struct prod *)0, s);
    return make_shared<query_spec>((struct prod *)0, s);
  } catch (runtime_error &e) {
    return statement_factory(s);
  }
}

void common_table_expression::accept(prod_visitor *v)
{
  v->visit(this);
  for(auto q : with_queries)
    q->accept(v);
  query->accept(v);
}

common_table_expression::common_table_expression(prod *parent, struct scope *s)
  : prod(parent), myscope(s)
{
  scope = &myscope;
  do {
    shared_ptr<query_spec> query = make_shared<query_spec>(this, s);
    with_queries.push_back(query);
    string alias = scope->stmt_uid("jennifer");
    relation *relation = &query->select_list->derived_table;
    auto aliased_rel = make_shared<aliased_relation>(alias, relation);
    refs.push_back(aliased_rel);
    scope->tables.push_back(&*aliased_rel);

  } while (d6() > 2);

 retry:
  do {
    auto pick = random_pick(s->tables);
    scope->tables.push_back(pick);
  } while (d6() > 3);
  try {
    query = make_shared<query_spec>(this, scope);
  } catch (runtime_error &e) {
    retry();
    goto retry;
  }

}

void common_table_expression::out(std::ostream &out)
{
  out << "WITH " ;
  for (size_t i = 0; i < with_queries.size(); i++) {
    indent(out);
    out << refs[i]->ident() << " AS " << "(" << *with_queries[i] << ")";
    if (i+1 != with_queries.size())
      out << ", ";
    indent(out);
  }
  out << *query;
  indent(out);
}

merge_stmt::merge_stmt(prod *p, struct scope *s, table *v)
     : modifying_stmt(p,s,v) {
  match();
  target_table_ = make_shared<target_table>(this, victim);
  data_source = table_ref::factory(this);
//   join_condition = join_cond::factory(this, *target_table_, *data_source);
  join_condition = make_shared<simple_join_cond>(this, *target_table_, *data_source);


  /* Put data_source into scope but not target_table.  Visibility of
     the latter varies depending on kind of when clause. */
//   for (auto r : data_source->refs)
//     scope->refs.push_back(&*r);

  clauselist.push_back(when_clause::factory(this));
  while (d6()>4)
    clauselist.push_back(when_clause::factory(this));
}

void merge_stmt::out(std::ostream &out)
{
     out << "MERGE INTO " << *target_table_;
     indent(out);
     out << "USING " << *data_source;
     indent(out);
     out << "ON " << *join_condition;
     indent(out);
     for (auto p : clauselist) {
       out << *p;
       indent(out);
     }
}

void merge_stmt::accept(prod_visitor *v)
{
  v->visit(this);
  target_table_->accept(v);
  data_source->accept(v);
  join_condition->accept(v);
  for (auto p : clauselist)
    p->accept(v);
    
}

when_clause::when_clause(merge_stmt *p)
  : prod(p)
{
  condition = bool_expr::factory(this);
  matched = d6() > 3;
}

void when_clause::out(std::ostream &out)
{
  out << (matched ? "WHEN MATCHED " : "WHEN NOT MATCHED");
  indent(out);
  out << "AND " << *condition;
  indent(out);
  out << " THEN ";
  out << (matched ? "DELETE" : "DO NOTHING");
}

void when_clause::accept(prod_visitor *v)
{
  v->visit(this);
  condition->accept(v);
}

when_clause_update::when_clause_update(merge_stmt *p)
  : when_clause(p), myscope(p->scope)
{
  myscope.tables = scope->tables;
  myscope.refs = scope->refs;
  scope = &myscope;
  scope->refs.push_back(&*(p->target_table_->refs[0]));
  
  set_list = std::make_shared<struct set_list>(this, p->victim);
}

void when_clause_update::out(std::ostream &out) {
  out << "WHEN MATCHED AND " << *condition;
  indent(out);
  out << " THEN UPDATE " << *set_list;
}

void when_clause_update::accept(prod_visitor *v)
{
  v->visit(this);
  set_list->accept(v);
}


when_clause_insert::when_clause_insert(struct merge_stmt *p)
  : when_clause(p)
{
  for (auto col : p->victim->columns()) {
    auto expr = value_expr::factory(this, col.type);
    assert(expr->type == col.type);
    exprs.push_back(expr);
  }
}

void when_clause_insert::out(std::ostream &out) {
  out << "WHEN NOT MATCHED AND " << *condition;
  indent(out);
  out << " THEN INSERT VALUES ( ";

  for (auto expr = exprs.begin();
       expr != exprs.end();
       expr++) {
    out << **expr;
    if (expr+1 != exprs.end())
      out << ", ";
  }
  out << ")";

}

void when_clause_insert::accept(prod_visitor *v)
{
  v->visit(this);
  for (auto p : exprs)
    p->accept(v);
}

shared_ptr<when_clause> when_clause::factory(struct merge_stmt *p)
{
  try {
    switch(d6()) {
    case 1:
    case 2:
      return make_shared<when_clause_insert>(p);
    case 3:
    case 4:
      return make_shared<when_clause_update>(p);
    default:
      return make_shared<when_clause>(p);
    }
  } catch (runtime_error &e) {
    p->retry();
  }
  return factory(p);
}