<?php

/**

 * @file

 * Database schema code for PostgreSQL database servers.

 */

/**

 * @ingroup schemaapi

 * @{

 */

class DatabaseSchema_pgsql extends DatabaseSchema {

  /**

   * A cache of information about blob columns and sequences of tables.

   *

   * This is collected by DatabaseConnection_pgsql->queryTableInformation(),

   * by introspecting the database.

   *

   * @see DatabaseConnection_pgsql->queryTableInformation()

   * @var array

   */

  protected $tableInformation = array();

  /**

   * Fetch the list of blobs and sequences used on a table.

   *

   * We introspect the database to collect the information required by insert

   * and update queries.

   *

   * @param $table_name

   *   The non-prefixed name of the table.

   * @return

   *   An object with two member variables:

   *     - 'blob_fields' that lists all the blob fields in the table.

   *     - 'sequences' that lists the sequences used in that table.

   */

  public function queryTableInformation($table) {

    // Generate a key to reference this table's information on.

    $key = $this->connection->prefixTables('{' . $table . '}');

    if (!strpos($key, '.')) {

      $key = 'public.' . $key;

    }

    if (!isset($this->tableInformation[$key])) {

      // Split the key into schema and table for querying.

      list($schema, $table_name) = explode('.', $key);

      $table_information = (object) array(

        'blob_fields' => array(),

        'sequences' => array(),

      );

      // Don't use {} around information_schema.columns table.

      $result = $this->connection->query("SELECT column_name, data_type, column_default FROM information_schema.columns WHERE table_schema = :schema AND table_name = :table AND (data_type = 'bytea' OR (numeric_precision IS NOT NULL AND column_default LIKE :default))", array(

        ':schema' => $schema,

        ':table' => $table_name,

        ':default' => '%nextval%',

      ));

      foreach ($result as $column) {

        if ($column->data_type == 'bytea') {

          $table_information->blob_fields[$column->column_name] = TRUE;

        }

        elseif (preg_match("/nextval\('([^']+)'/", $column->column_default, $matches)) {

          // We must know of any sequences in the table structure to help us

          // return the last insert id. If there is more than 1 sequences the

          // first one (index 0 of the sequences array) will be used.

          $table_information->sequences[] = $matches[1];

          $table_information->serial_fields[] = $column->column_name;

        }

      }

      $this->tableInformation[$key] = $table_information;

    }

    return $this->tableInformation[$key];

  }

  /**

   * Fetch the list of CHECK constraints used on a field.

   *

   * We introspect the database to collect the information required by field

   * alteration.

   *

   * @param $table

   *   The non-prefixed name of the table.

   * @param $field

   *   The name of the field.

   * @return

   *   An array of all the checks for the field.

   */

  public function queryFieldInformation($table, $field) {

    $prefixInfo = $this->getPrefixInfo($table, TRUE);

    // Split the key into schema and table for querying.

    $schema = $prefixInfo['schema'];

    $table_name = $prefixInfo['table'];

    $field_information = (object) array(

        'checks' => array(),

    );

    $checks = $this->connection->query("SELECT conname FROM pg_class cl INNER JOIN pg_constraint co ON co.conrelid = cl.oid INNER JOIN pg_attribute attr ON attr.attrelid = cl.oid AND attr.attnum = ANY (co.conkey) INNER JOIN pg_namespace ns ON cl.relnamespace = ns.oid WHERE co.contype = 'c' AND ns.nspname = :schema AND cl.relname = :table AND attr.attname = :column", array(

      ':schema' => $schema,

      ':table' => $table_name,

      ':column' => $field,

    ));

    $field_information = $checks->fetchCol();

    return $field_information;

  }

  /**

   * Generate SQL to create a new table from a Drupal schema definition.

   *

   * @param $name

   *   The name of the table to create.

   * @param $table

   *   A Schema API table definition array.

   * @return

   *   An array of SQL statements to create the table.

   */

  protected function createTableSql($name, $table) {

    $sql_fields = array();

    foreach ($table['fields'] as $field_name => $field) {

      $sql_fields[] = $this->createFieldSql($field_name, $this->processField($field));

    }

    $sql_keys = array();

    if (isset($table['primary key']) && is_array($table['primary key'])) {

      $sql_keys[] = 'PRIMARY KEY (' . implode(', ', $table['primary key']) . ')';

    }

    if (isset($table['unique keys']) && is_array($table['unique keys'])) {

      foreach ($table['unique keys'] as $key_name => $key) {

        $sql_keys[] = 'CONSTRAINT ' . $this->prefixNonTable($name, $key_name, 'key') . ' UNIQUE (' . implode(', ', $key) . ')';

      }

    }

    $sql = "CREATE TABLE {" . $name . "} (\n\t";

    $sql .= implode(",\n\t", $sql_fields);

    if (count($sql_keys) > 0) {

      $sql .= ",\n\t";

    }

    $sql .= implode(",\n\t", $sql_keys);

    $sql .= "\n)";

    $statements[] = $sql;

    if (isset($table['indexes']) && is_array($table['indexes'])) {

      foreach ($table['indexes'] as $key_name => $key) {

        $statements[] = $this->_createIndexSql($name, $key_name, $key);

      }

    }

    // Add table comment.

    if (!empty($table['description'])) {

      $statements[] = 'COMMENT ON TABLE {' . $name . '} IS ' . $this->prepareComment($table['description']);

    }

    // Add column comments.

    foreach ($table['fields'] as $field_name => $field) {

      if (!empty($field['description'])) {

        $statements[] = 'COMMENT ON COLUMN {' . $name . '}.' . $field_name . ' IS ' . $this->prepareComment($field['description']);

      }

    }

    return $statements;

  }

  /**

   * Create an SQL string for a field to be used in table creation or

   * alteration.

   *

   * Before passing a field out of a schema definition into this

   * function it has to be processed by _db_process_field().

   *

   * @param $name

   *    Name of the field.

   * @param $spec

   *    The field specification, as per the schema data structure format.

   */

  protected function createFieldSql($name, $spec) {

    $sql = $name . ' ' . $spec['pgsql_type'];

    if (isset($spec['type']) && $spec['type'] == 'serial') {

      unset($spec['not null']);

    }

    if (in_array($spec['pgsql_type'], array('varchar', 'character', 'text')) && isset($spec['length'])) {

      $sql .= '(' . $spec['length'] . ')';

    }

    elseif (isset($spec['precision']) && isset($spec['scale'])) {

      $sql .= '(' . $spec['precision'] . ', ' . $spec['scale'] . ')';

    }

    if (!empty($spec['unsigned'])) {

      $sql .= " CHECK ($name >= 0)";

    }

    if (isset($spec['not null'])) {

      if ($spec['not null']) {

        $sql .= ' NOT NULL';

      }

      else {

        $sql .= ' NULL';

      }

    }

    if (isset($spec['default'])) {

      $default = is_string($spec['default']) ? "'" . $spec['default'] . "'" : $spec['default'];

      $sql .= " default $default";

    }

    return $sql;

  }

  /**

   * Set database-engine specific properties for a field.

   *

   * @param $field

   *   A field description array, as specified in the schema documentation.

   */

  protected function processField($field) {

    if (!isset($field['size'])) {

      $field['size'] = 'normal';

    }

    // Set the correct database-engine specific datatype.

    // In case one is already provided, force it to lowercase.

    if (isset($field['pgsql_type'])) {

      $field['pgsql_type'] = drupal_strtolower($field['pgsql_type']);

    }

    else {

      $map = $this->getFieldTypeMap();

      $field['pgsql_type'] = $map[$field['type'] . ':' . $field['size']];

    }

    if (!empty($field['unsigned'])) {

      // Unsigned datatypes are not supported in PostgreSQL 8.3. In MySQL,

      // they are used to ensure a positive number is inserted and it also

      // doubles the maximum integer size that can be stored in a field.

      // The PostgreSQL schema in Drupal creates a check constraint

      // to ensure that a value inserted is >= 0. To provide the extra

      // integer capacity, here, we bump up the column field size.

      if (!isset($map)) {

        $map = $this->getFieldTypeMap();

      }

      switch ($field['pgsql_type']) {

        case 'smallint':

          $field['pgsql_type'] = $map['int:medium'];

          break;

        case 'int' :

          $field['pgsql_type'] = $map['int:big'];

          break;

      }

    }

    if (isset($field['type']) && $field['type'] == 'serial') {

      unset($field['not null']);

    }

    return $field;

  }

  /**

   * This maps a generic data type in combination with its data size

   * to the engine-specific data type.

   */

  function getFieldTypeMap() {

    // Put :normal last so it gets preserved by array_flip. This makes

    // it much easier for modules (such as schema.module) to map

    // database types back into schema types.

    // $map does not use drupal_static as its value never changes.

    static $map = array(

      'varchar:normal' => 'varchar',

      'char:normal' => 'character',

      'text:tiny' => 'text',

      'text:small' => 'text',

      'text:medium' => 'text',

      'text:big' => 'text',

      'text:normal' => 'text',

      'int:tiny' => 'smallint',

      'int:small' => 'smallint',

      'int:medium' => 'int',

      'int:big' => 'bigint',

      'int:normal' => 'int',

      'float:tiny' => 'real',

      'float:small' => 'real',

      'float:medium' => 'real',

      'float:big' => 'double precision',

      'float:normal' => 'real',

      'numeric:normal' => 'numeric',

      'blob:big' => 'bytea',

      'blob:normal' => 'bytea',

      'serial:tiny' => 'serial',

      'serial:small' => 'serial',

      'serial:medium' => 'serial',

      'serial:big' => 'bigserial',

      'serial:normal' => 'serial',

      );

    return $map;

  }

  protected function _createKeySql($fields) {

    $return = array();

    foreach ($fields as $field) {

      if (is_array($field)) {

        $return[] = 'substr(' . $field[0] . ', 1, ' . $field[1] . ')';

      }

      else {

        $return[] = '"' . $field . '"';

      }

    }

    return implode(', ', $return);

  }

  function renameTable($table, $new_name) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot rename @table to @table_new: table @table doesn't exist.", array('@table' => $table, '@table_new' => $new_name)));

    }

    if ($this->tableExists($new_name)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot rename @table to @table_new: table @table_new already exists.", array('@table' => $table, '@table_new' => $new_name)));

    }

    // Get the schema and tablename for the old table.

    $old_full_name = $this->connection->prefixTables('{' . $table . '}');

    list($old_schema, $old_table_name) = strpos($old_full_name, '.') ? explode('.', $old_full_name) : array('public', $old_full_name);

    // Index names and constraint names are global in PostgreSQL, so we need to

    // rename them when renaming the table.

    $indexes = $this->connection->query('SELECT indexname FROM pg_indexes WHERE schemaname = :schema AND tablename = :table', array(':schema' => $old_schema, ':table' => $old_table_name));

    foreach ($indexes as $index) {

      if (preg_match('/^' . preg_quote($old_full_name) . '_(.*)$/', $index->indexname, $matches)) {

        $index_name = $matches[1];

        $this->connection->query('ALTER INDEX ' . $index->indexname . ' RENAME TO {' . $new_name . '}_' . $index_name);

      }

    }

    // Now rename the table.

    // Ensure the new table name does not include schema syntax.

    $prefixInfo = $this->getPrefixInfo($new_name);

    $this->connection->query('ALTER TABLE {' . $table . '} RENAME TO ' . $prefixInfo['table']);

  }

  public function dropTable($table) {

    if (!$this->tableExists($table)) {

      return FALSE;

    }

    $this->connection->query('DROP TABLE {' . $table . '}');

    return TRUE;

  }

  public function addField($table, $field, $spec, $new_keys = array()) {

    if (!$this->tableExists($table)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add field @table.@field: table doesn't exist.", array('@field' => $field, '@table' => $table)));

    }

    if ($this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectExistsException(t("Cannot add field @table.@field: field already exists.", array('@field' => $field, '@table' => $table)));

    }

    $fixnull = FALSE;

    if (!empty($spec['not null']) && !isset($spec['default'])) {

      $fixnull = TRUE;

      $spec['not null'] = FALSE;

    }

    $query = 'ALTER TABLE {' . $table . '} ADD COLUMN ';

    $query .= $this->createFieldSql($field, $this->processField($spec));

    $this->connection->query($query);

    if (isset($spec['initial'])) {

      $this->connection->update($table)

        ->fields(array($field => $spec['initial']))

        ->execute();

    }

    if ($fixnull) {

      $this->connection->query("ALTER TABLE {" . $table . "} ALTER $field SET NOT NULL");

    }

    if (isset($new_keys)) {

      $this->_createKeys($table, $new_keys);

    }

    // Add column comment.

    if (!empty($spec['description'])) {

      $this->connection->query('COMMENT ON COLUMN {' . $table . '}.' . $field . ' IS ' . $this->prepareComment($spec['description']));

    }

  }

  public function dropField($table, $field) {

    if (!$this->fieldExists($table, $field)) {

      return FALSE;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} DROP COLUMN "' . $field . '"');

    return TRUE;

  }

  public function fieldSetDefault($table, $field, $default) {

    if (!$this->fieldExists($table, $field)) {

      throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot set default value of field @table.@field: field doesn't exist.", array('@table' => $table, '@field' => $field)));

    }

    if (!isset($default)) {

      $default = 'NULL';

    }

    else {

      $default = is_string($default) ? "'$default'" : $default;

    }

    $this->connection->query('ALTER TABLE {' . $table . '} ALTER COLUMN "' . $field . '" SET DEFAULT ' . $default);