Builder.php

<?php

namespace Illuminate\Database\Schema;

use Closure;
use Illuminate\Database\Connection;

class Builder
{
    /**
     * The database connection instance.
     *
     * @var \Illuminate\Database\Connection
     */
    protected $connection;

    /**
     * The schema grammar instance.
     *
     * @var \Illuminate\Database\Schema\Grammars\Grammar
     */
    protected $grammar;

    /**
     * The Blueprint resolver callback.
     *
     * @var \Closure
     */
    protected $resolver;

    /**
     * Create a new database Schema manager.
     *
     * @param  \Illuminate\Database\Connection  $connection
     * @return void
     */
    public function __construct(Connection $connection)
    {
        $this->connection = $connection;
        $this->grammar = $connection->getSchemaGrammar();
    }

    /**
     * Determine if the given table exists.
     *
     * @param  string  $table
     * @return bool
     */
    public function hasTable($table)
    {
        $sql = $this->grammar->compileTableExists();

        $table = $this->connection->getTablePrefix().$table;

        return count($this->connection->select($sql, [$table])) > 0;
    }

    /**
     * Determine if the given table has a given column.
     *
     * @param  string  $table
     * @param  string  $column
     * @return bool
     */
    public function hasColumn($table, $column)
    {
        $column = strtolower($column);

        return in_array($column, array_map('strtolower', $this->getColumnListing($table)));
    }

    /**
     * Determine if the given table has given columns.
     *
     * @param  string  $table
     * @param  array   $columns
     * @return bool
     */
    public function hasColumns($table, array $columns)
    {
        $tableColumns = array_map('strtolower', $this->getColumnListing($table));

        foreach ($columns as $column) {
            if (! in_array(strtolower($column), $tableColumns)) {
                return false;
            }
        }

        return true;
    }

    /**
     * Get the column listing for a given table.
     *
     * @param  string  $table
     * @return array
     */
    public function getColumnListing($table)
    {
        $table = $this->connection->getTablePrefix().$table;

        $results = $this->connection->select($this->grammar->compileColumnExists($table));

        return $this->connection->getPostProcessor()->processColumnListing($results);
    }

    /**
     * Modify a table on the schema.
     *
     * @param  string    $table
     * @param  \Closure  $callback
     * @return \Illuminate\Database\Schema\Blueprint
     */
    public function table($table, Closure $callback)
    {
        $this->build($this->createBlueprint($table, $callback));
    }

    /**
     * Create a new table on the schema.
     *
     * @param  string    $table
     * @param  \Closure  $callback
     * @return \Illuminate\Database\Schema\Blueprint
     */
    public function create($table, Closure $callback)
    {
        $blueprint = $this->createBlueprint($table);

        $blueprint->create();

        $callback($blueprint);

        $this->build($blueprint);
    }

    /**
     * Drop a table from the schema.
     *
     * @param  string  $table
     * @return \Illuminate\Database\Schema\Blueprint
     */
    public function drop($table)
    {
        $blueprint = $this->createBlueprint($table);

        $blueprint->drop();

        $this->build($blueprint);
    }

    /**
     * Drop a table from the schema if it exists.
     *
     * @param  string  $table
     * @return \Illuminate\Database\Schema\Blueprint
     */
    public function dropIfExists($table)
    {
        $blueprint = $this->createBlueprint($table);

        $blueprint->dropIfExists();

        $this->build($blueprint);
    }

    /**
     * Rename a table on the schema.
     *
     * @param  string  $from
     * @param  string  $to
     * @return \Illuminate\Database\Schema\Blueprint
     */
    public function rename($from, $to)
    {
        $blueprint = $this->createBlueprint($from);

        $blueprint->rename($to);

        $this->build($blueprint);
    }

    /**
     * Execute the blueprint to build / modify the table.
     *
     * @param  \Illuminate\Database\Schema\Blueprint  $blueprint
     * @return void
     */
    protected function build(Blueprint $blueprint)
    {
        $blueprint->build($this->connection, $this->grammar);
    }

    /**
     * Create a new command set with a Closure.
     *
     * @param  string  $table
     * @param  \Closure|null  $callback
     * @return \Illuminate\Database\Schema\Blueprint
     */
    protected function createBlueprint($table, Closure $callback = null)
    {
        if (isset($this->resolver)) {
            return call_user_func($this->resolver, $table, $callback);
        }

        return new Blueprint($table, $callback);
    }

    /**
     * Get the database connection instance.
     *
     * @return \Illuminate\Database\Connection
     */
    public function getConnection()
    {
        return $this->connection;
    }

    /**
     * Set the database connection instance.
     *
     * @param  \Illuminate\Database\Connection  $connection
     * @return $this
     */
    public function setConnection(Connection $connection)
    {
        $this->connection = $connection;

        return $this;
    }

    /**
     * Set the Schema Blueprint resolver callback.
     *
     * @param  \Closure  $resolver
     * @return void
     */
    public function blueprintResolver(Closure $resolver)
    {
        $this->resolver = $resolver;
    }
}