relmodel.hh

/// @file
/// @brief supporting classes for the grammar

#ifndef RELMODEL_HH
#define RELMODEL_HH
#include <string>
#include <vector>
#include <map>
#include <utility>
#include <memory>
#include <cassert>

using std::string;
using std::vector;
using std::map;
using std::pair;
using std::make_pair;
using std::shared_ptr;

struct sqltype {
  string name;
  static map<string, struct sqltype*> typemap;
  static struct sqltype *get(string s);
  sqltype(string n) : name(n) { }

  /** This function is used to model postgres-style pseudotypes.
      A generic type is consistent with a more concrete type.
      E.G., anyarray->consistent(intarray) is true
            while int4array->consistent(anyarray) is false

      There must not be cycles in the consistency graph, since the
      grammar will use fixpoint iteration to resolve type conformance
      situations in the direction of more concrete types  */
  virtual bool consistent(struct sqltype *rvalue);
};

struct column {
  string name;
  sqltype *type;
  column(string name) : name(name) { }
  column(string name, sqltype *t) : name(name), type(t) {
    assert(t);
  }
};

struct relation {
  vector<column> cols;
  virtual vector<column> &columns() { return cols; }
};

struct named_relation : relation {
  string name;
  virtual string ident() { return name; }
  virtual ~named_relation() { }
  named_relation(string n) : name(n) { }
};

struct aliased_relation : named_relation {
  relation *rel;
  virtual ~aliased_relation() { }
  aliased_relation(string n, relation* r) : named_relation(n), rel(r) { }
  virtual vector<column>& columns() { return rel->columns(); }
};

struct table : named_relation {
  string db;
  string schema;
  bool is_base_table;
  vector<string> constraints;
  table(string name, string schema, string db, bool base_table)
    : named_relation(name),
      schema(schema),
      db(db),
      is_base_table(base_table) { }
  virtual string ident() { return db.empty() ? (schema + "." + name) : (db + "." + schema + "." + name); }
  virtual ~table() { };
};

struct scope {
  struct scope *parent;
  /// available to table_ref productions
  vector<named_relation*> tables;
 /// available to column_ref productions
  vector<named_relation*> refs;
  struct schema *schema;
  /// Counters for prefixed stmt-unique identifiers
  shared_ptr<map<string,unsigned int> > stmt_seq;
  scope(struct scope *parent = 0) : parent(parent) {
    if (parent) {
      schema = parent->schema;
      tables = parent->tables;
      refs = parent->refs;
      stmt_seq = parent->stmt_seq;
    }
  }
  vector<pair<named_relation*, column> > refs_of_type(sqltype *t) {
    vector<pair<named_relation*, column> > result;
    for (auto r : refs)
      for (auto c : r->columns())
	if (t->consistent(c.type))
	  result.push_back(make_pair(r,c));
    return result;
  }
  /** Generate unique identifier with prefix. */
  string stmt_uid(const char* prefix) {
    string result(prefix);
    result += "_";
    result += std::to_string((*stmt_seq)[result]++);
    return result;
  }
  /** Reset unique identifier counters. */
  void new_stmt() {
    stmt_seq = std::make_shared<map<string,unsigned int> >();
  }
};

struct op {
  string name;
  sqltype *left;
  sqltype *right;
  sqltype *result;
  op(string n,sqltype *l,sqltype *r, sqltype *res)
    : name(n), left(l), right(r), result(res) { }
  op() { }
};

struct routine {
  string specific_name;
  string schema;
  vector<sqltype *> argtypes;
  sqltype *restype;
  string name;
  bool returns_set;
  routine(string schema, string specific_name, sqltype* data_type, string name, bool returns_set=false)
    : specific_name(specific_name), schema(schema), restype(data_type), name(name), returns_set(returns_set) {
    assert(data_type);
  }
  virtual string ident() {
    if (schema.size())
      return schema + "." + name;
    else
      return name;
  }
};

#endif