diff options
Diffstat (limited to 'activerecord/lib/arel/select_manager.rb')
| -rw-r--r-- | activerecord/lib/arel/select_manager.rb | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/activerecord/lib/arel/select_manager.rb b/activerecord/lib/arel/select_manager.rb new file mode 100644 index 0000000000..22a04b00c6 --- /dev/null +++ b/activerecord/lib/arel/select_manager.rb @@ -0,0 +1,273 @@ +# frozen_string_literal: true + +module Arel # :nodoc: all + class SelectManager < Arel::TreeManager + include Arel::Crud + + STRING_OR_SYMBOL_CLASS = [Symbol, String] + + def initialize(table = nil) + super() + @ast = Nodes::SelectStatement.new + @ctx = @ast.cores.last + from table + end + + def initialize_copy(other) + super + @ctx = @ast.cores.last + end + + def limit + @ast.limit && @ast.limit.expr + end + alias :taken :limit + + def constraints + @ctx.wheres + end + + def offset + @ast.offset && @ast.offset.expr + end + + def skip(amount) + if amount + @ast.offset = Nodes::Offset.new(amount) + else + @ast.offset = nil + end + self + end + alias :offset= :skip + + ### + # Produces an Arel::Nodes::Exists node + def exists + Arel::Nodes::Exists.new @ast + end + + def as(other) + create_table_alias grouping(@ast), Nodes::SqlLiteral.new(other) + end + + def lock(locking = Arel.sql("FOR UPDATE")) + case locking + when true + locking = Arel.sql("FOR UPDATE") + when Arel::Nodes::SqlLiteral + when String + locking = Arel.sql locking + end + + @ast.lock = Nodes::Lock.new(locking) + self + end + + def locked + @ast.lock + end + + def on(*exprs) + @ctx.source.right.last.right = Nodes::On.new(collapse(exprs)) + self + end + + def group(*columns) + columns.each do |column| + # FIXME: backwards compat + column = Nodes::SqlLiteral.new(column) if String === column + column = Nodes::SqlLiteral.new(column.to_s) if Symbol === column + + @ctx.groups.push Nodes::Group.new column + end + self + end + + def from(table) + table = Nodes::SqlLiteral.new(table) if String === table + + case table + when Nodes::Join + @ctx.source.right << table + else + @ctx.source.left = table + end + + self + end + + def froms + @ast.cores.map { |x| x.from }.compact + end + + def join(relation, klass = Nodes::InnerJoin) + return self unless relation + + case relation + when String, Nodes::SqlLiteral + raise EmptyJoinError if relation.empty? + klass = Nodes::StringJoin + end + + @ctx.source.right << create_join(relation, nil, klass) + self + end + + def outer_join(relation) + join(relation, Nodes::OuterJoin) + end + + def having(expr) + @ctx.havings << expr + self + end + + def window(name) + window = Nodes::NamedWindow.new(name) + @ctx.windows.push window + window + end + + def project(*projections) + # FIXME: converting these to SQLLiterals is probably not good, but + # rails tests require it. + @ctx.projections.concat projections.map { |x| + STRING_OR_SYMBOL_CLASS.include?(x.class) ? Nodes::SqlLiteral.new(x.to_s) : x + } + self + end + + def projections + @ctx.projections + end + + def projections=(projections) + @ctx.projections = projections + end + + def distinct(value = true) + if value + @ctx.set_quantifier = Arel::Nodes::Distinct.new + else + @ctx.set_quantifier = nil + end + self + end + + def distinct_on(value) + if value + @ctx.set_quantifier = Arel::Nodes::DistinctOn.new(value) + else + @ctx.set_quantifier = nil + end + self + end + + def order(*expr) + # FIXME: We SHOULD NOT be converting these to SqlLiteral automatically + @ast.orders.concat expr.map { |x| + STRING_OR_SYMBOL_CLASS.include?(x.class) ? Nodes::SqlLiteral.new(x.to_s) : x + } + self + end + + def orders + @ast.orders + end + + def where_sql(engine = Table.engine) + return if @ctx.wheres.empty? + + viz = Visitors::WhereSql.new(engine.connection.visitor, engine.connection) + Nodes::SqlLiteral.new viz.accept(@ctx, Collectors::SQLString.new).value + end + + def union(operation, other = nil) + if other + node_class = Nodes.const_get("Union#{operation.to_s.capitalize}") + else + other = operation + node_class = Nodes::Union + end + + node_class.new self.ast, other.ast + end + + def intersect(other) + Nodes::Intersect.new ast, other.ast + end + + def except(other) + Nodes::Except.new ast, other.ast + end + alias :minus :except + + def lateral(table_name = nil) + base = table_name.nil? ? ast : as(table_name) + Nodes::Lateral.new(base) + end + + def with(*subqueries) + if subqueries.first.is_a? Symbol + node_class = Nodes.const_get("With#{subqueries.shift.to_s.capitalize}") + else + node_class = Nodes::With + end + @ast.with = node_class.new(subqueries.flatten) + + self + end + + def take(limit) + if limit + @ast.limit = Nodes::Limit.new(limit) + @ctx.top = Nodes::Top.new(limit) + else + @ast.limit = nil + @ctx.top = nil + end + self + end + alias limit= take + + def join_sources + @ctx.source.right + end + + def source + @ctx.source + end + + class Row < Struct.new(:data) # :nodoc: + def id + data["id"] + end + + def method_missing(name, *args) + name = name.to_s + return data[name] if data.key?(name) + super + end + end + + private + def collapse(exprs, existing = nil) + exprs = exprs.unshift(existing.expr) if existing + exprs = exprs.compact.map { |expr| + if String === expr + # FIXME: Don't do this automatically + Arel.sql(expr) + else + expr + end + } + + if exprs.length == 1 + exprs.first + else + create_and exprs + end + end + end +end |