Checkout of Instiki Trunk 1/21/2007.

vendor/plugins/sqlite3-ruby/sqlite3/pragmas.rb

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+#--
+# =============================================================================
+# Copyright (c) 2004, Jamis Buck (jgb3@email.byu.edu)
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+# 
+#     * Redistributions of source code must retain the above copyright notice,
+#       this list of conditions and the following disclaimer.
+# 
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in the
+#       documentation and/or other materials provided with the distribution.
+# 
+#     * The names of its contributors may not be used to endorse or promote
+#       products derived from this software without specific prior written
+#       permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# =============================================================================
+#++
+
+require 'sqlite3/errors'
+
+module SQLite3
+
+  # This module is intended for inclusion solely by the Database class. It
+  # defines convenience methods for the various pragmas supported by SQLite3.
+  #
+  # For a detailed description of these pragmas, see the SQLite3 documentation
+  # at http://sqlite.org/pragma.html.
+  module Pragmas
+
+    # Returns +true+ or +false+ depending on the value of the named pragma.
+    def get_boolean_pragma( name )
+      get_first_value( "PRAGMA #{name}" ) != "0"
+    end
+    private :get_boolean_pragma
+
+    # Sets the given pragma to the given boolean value. The value itself
+    # may be +true+ or +false+, or any other commonly used string or
+    # integer that represents truth.
+    def set_boolean_pragma( name, mode )
+      case mode
+        when String
+          case mode.downcase
+            when "on", "yes", "true", "y", "t": mode = "'ON'"
+            when "off", "no", "false", "n", "f": mode = "'OFF'"
+            else
+              raise Exception,
+                "unrecognized pragma parameter #{mode.inspect}"
+          end
+        when true, 1
+          mode = "ON"
+        when false, 0, nil
+          mode = "OFF"
+        else
+          raise Exception,
+            "unrecognized pragma parameter #{mode.inspect}"
+      end
+
+      execute( "PRAGMA #{name}=#{mode}" )
+    end
+    private :set_boolean_pragma
+
+    # Requests the given pragma (and parameters), and if the block is given,
+    # each row of the result set will be yielded to it. Otherwise, the results
+    # are returned as an array.
+    def get_query_pragma( name, *parms, &block ) # :yields: row
+      if parms.empty?
+        execute( "PRAGMA #{name}", &block )
+      else
+        args = "'" + parms.join("','") + "'"
+        execute( "PRAGMA #{name}( #{args} )", &block )
+      end
+    end
+    private :get_query_pragma
+
+    # Return the value of the given pragma.
+    def get_enum_pragma( name )
+      get_first_value( "PRAGMA #{name}" )
+    end
+    private :get_enum_pragma
+
+    # Set the value of the given pragma to +mode+. The +mode+ parameter must
+    # conform to one of the values in the given +enum+ array. Each entry in
+    # the array is another array comprised of elements in the enumeration that
+    # have duplicate values. See #synchronous, #default_synchronous,
+    # #temp_store, and #default_temp_store for usage examples.
+    def set_enum_pragma( name, mode, enums )
+      match = enums.find { |p| p.find { |i| i.to_s.downcase == mode.to_s.downcase } }
+      raise Exception,
+        "unrecognized #{name} #{mode.inspect}" unless match
+      execute( "PRAGMA #{name}='#{match.first.upcase}'" )
+    end
+    private :set_enum_pragma
+
+    # Returns the value of the given pragma as an integer.
+    def get_int_pragma( name )
+      get_first_value( "PRAGMA #{name}" ).to_i
+    end
+    private :get_int_pragma
+
+    # Set the value of the given pragma to the integer value of the +value+
+    # parameter.
+    def set_int_pragma( name, value )
+      execute( "PRAGMA #{name}=#{value.to_i}" )
+    end
+    private :set_int_pragma
+
+    # The enumeration of valid synchronous modes.
+    SYNCHRONOUS_MODES = [ [ 'full', 2 ], [ 'normal', 1 ], [ 'off', 0 ] ]
+
+    # The enumeration of valid temp store modes.
+    TEMP_STORE_MODES  = [ [ 'default', 0 ], [ 'file', 1 ], [ 'memory', 2 ] ]
+
+    # Does an integrity check on the database. If the check fails, a
+    # SQLite3::Exception will be raised. Otherwise it
+    # returns silently.
+    def integrity_check
+      execute( "PRAGMA integrity_check" ) do |row|
+        raise Exception, row[0] if row[0] != "ok"
+      end
+    end
+
+    def auto_vacuum
+      get_boolean_pragma "auto_vacuum"
+    end
+
+    def auto_vacuum=( mode )
+      set_boolean_pragma "auto_vacuum", mode
+    end
+
+    def schema_cookie
+      get_int_pragma "schema_cookie"
+    end
+
+    def schema_cookie=( cookie )
+      set_int_pragma "schema_cookie", cookie
+    end
+
+    def user_cookie
+      get_int_pragma "user_cookie"
+    end
+
+    def user_cookie=( cookie )
+      set_int_pragma "user_cookie", cookie
+    end
+
+    def cache_size
+      get_int_pragma "cache_size"
+    end
+
+    def cache_size=( size )
+      set_int_pragma "cache_size", size
+    end
+
+    def default_cache_size
+      get_int_pragma "default_cache_size"
+    end
+
+    def default_cache_size=( size )
+      set_int_pragma "default_cache_size", size
+    end
+
+    def default_synchronous
+      get_enum_pragma "default_synchronous"
+    end
+
+    def default_synchronous=( mode )
+      set_enum_pragma "default_synchronous", mode, SYNCHRONOUS_MODES
+    end
+
+    def synchronous
+      get_enum_pragma "synchronous"
+    end
+
+    def synchronous=( mode )
+      set_enum_pragma "synchronous", mode, SYNCHRONOUS_MODES
+    end
+
+    def default_temp_store
+      get_enum_pragma "default_temp_store"
+    end
+
+    def default_temp_store=( mode )
+      set_enum_pragma "default_temp_store", mode, TEMP_STORE_MODES
+    end
+  
+    def temp_store
+      get_enum_pragma "temp_store"
+    end
+
+    def temp_store=( mode )
+      set_enum_pragma "temp_store", mode, TEMP_STORE_MODES
+    end
+
+    def full_column_names
+      get_boolean_pragma "full_column_names"
+    end
+
+    def full_column_names=( mode )
+      set_boolean_pragma "full_column_names", mode
+    end
+  
+    def parser_trace
+      get_boolean_pragma "parser_trace"
+    end
+
+    def parser_trace=( mode )
+      set_boolean_pragma "parser_trace", mode
+    end
+  
+    def vdbe_trace
+      get_boolean_pragma "vdbe_trace"
+    end
+
+    def vdbe_trace=( mode )
+      set_boolean_pragma "vdbe_trace", mode
+    end
+
+    def database_list( &block ) # :yields: row
+      get_query_pragma "database_list", &block
+    end
+
+    def foreign_key_list( table, &block ) # :yields: row
+      get_query_pragma "foreign_key_list", table, &block
+    end
+
+    def index_info( index, &block ) # :yields: row
+      get_query_pragma "index_info", index, &block
+    end
+
+    def index_list( table, &block ) # :yields: row
+      get_query_pragma "index_list", table, &block
+    end
+
+    def table_info( table, &block ) # :yields: row
+      get_query_pragma "table_info", table, &block
+    end
+  
+  end
+
+end