diff options
Diffstat (limited to 'lib/prism/node_find.rb')
| -rw-r--r-- | lib/prism/node_find.rb | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/lib/prism/node_find.rb b/lib/prism/node_find.rb new file mode 100644 index 0000000000..697ee430e8 --- /dev/null +++ b/lib/prism/node_find.rb @@ -0,0 +1,185 @@ +# frozen_string_literal: true +# :markup: markdown +#-- +# rbs_inline: enabled + +module Prism + # Finds the Prism AST node corresponding to a given Method, UnboundMethod, + # Proc, or Thread::Backtrace::Location. On CRuby, uses node_id from the + # instruction sequence for an exact match. On other implementations, falls + # back to best-effort matching by source location line number. + # + # This module is autoloaded so that programs that don't use Prism.find don't + # pay for its definition. + module NodeFind # :nodoc: + # Find the node for the given callable or backtrace location. + #-- + #: (Method | UnboundMethod | Proc | Thread::Backtrace::Location callable, bool rubyvm) -> Node? + def self.find(callable, rubyvm) + case callable + when Proc + if rubyvm + RubyVMCallableFind.new.find(callable) + elsif callable.lambda? + LineLambdaFind.new.find(callable) + else + LineProcFind.new.find(callable) + end + when Method, UnboundMethod + if rubyvm + RubyVMCallableFind.new.find(callable) + else + LineMethodFind.new.find(callable) + end + when Thread::Backtrace::Location + if rubyvm + RubyVMBacktraceLocationFind.new.find(callable) + else + LineBacktraceLocationFind.new.find(callable) + end + else + raise ArgumentError, "Expected a Method, UnboundMethod, Proc, or Thread::Backtrace::Location, got #{callable.class}" + end + end + + # Base class that handles parsing a file. + class Find + private + + # Parse the given file path, returning a ParseResult or nil. + #-- + #: (String? file) -> ParseResult? + def parse_file(file) + return unless file && File.readable?(file) + result = Prism.parse_file(file) + result if result.success? + end + end + + # Finds the AST node for a Method, UnboundMethod, or Proc using the node_id + # from the instruction sequence. + class RubyVMCallableFind < Find + # Find the node for the given callable using the ISeq node_id. + #-- + #: (Method | UnboundMethod | Proc callable) -> Node? + def find(callable) + return unless (source_location = callable.source_location) + return unless (result = parse_file(source_location[0])) + return unless (iseq = RubyVM::InstructionSequence.of(callable)) + + header = iseq.to_a[4] + return unless header[:parser] == :prism + + result.value.find { |node| node.node_id == header[:node_id] } + end + end + + # Finds the AST node for a Thread::Backtrace::Location using the node_id + # from the backtrace location. + class RubyVMBacktraceLocationFind < Find + # Find the node for the given backtrace location using node_id. + #-- + #: (Thread::Backtrace::Location location) -> Node? + def find(location) + file = location.absolute_path || location.path + return unless (result = parse_file(file)) + return unless RubyVM::AbstractSyntaxTree.respond_to?(:node_id_for_backtrace_location) + + node_id = RubyVM::AbstractSyntaxTree.node_id_for_backtrace_location(location) + + result.value.find { |node| node.node_id == node_id } + end + end + + # Finds the AST node for a Method or UnboundMethod using best-effort line + # matching. Used on non-CRuby implementations. + class LineMethodFind < Find + # Find the node for the given method by matching on name and line. + #-- + #: (Method | UnboundMethod callable) -> Node? + def find(callable) + return unless (source_location = callable.source_location) + return unless (result = parse_file(source_location[0])) + + name = callable.name + start_line = source_location[1] + + result.value.find do |node| + case node + when DefNode + node.name == name && node.location.start_line == start_line + when CallNode + node.block.is_a?(BlockNode) && node.location.start_line == start_line + else + false + end + end + end + end + + # Finds the AST node for a lambda using best-effort line matching. Used + # on non-CRuby implementations. + class LineLambdaFind < Find + # Find the node for the given lambda by matching on line. + #-- + #: (Proc callable) -> Node? + def find(callable) + return unless (source_location = callable.source_location) + return unless (result = parse_file(source_location[0])) + + start_line = source_location[1] + + result.value.find do |node| + case node + when LambdaNode + node.location.start_line == start_line + when CallNode + node.block.is_a?(BlockNode) && node.location.start_line == start_line + else + false + end + end + end + end + + # Finds the AST node for a non-lambda Proc using best-effort line + # matching. Used on non-CRuby implementations. + class LineProcFind < Find + # Find the node for the given proc by matching on line. + #-- + #: (Proc callable) -> Node? + def find(callable) + return unless (source_location = callable.source_location) + return unless (result = parse_file(source_location[0])) + + start_line = source_location[1] + + result.value.find do |node| + case node + when ForNode + node.location.start_line == start_line + when CallNode + node.block.is_a?(BlockNode) && node.location.start_line == start_line + else + false + end + end + end + end + + # Finds the AST node for a Thread::Backtrace::Location using best-effort + # line matching. Used on non-CRuby implementations. + class LineBacktraceLocationFind < Find + # Find the node for the given backtrace location by matching on line. + #-- + #: (Thread::Backtrace::Location location) -> Node? + def find(location) + file = location.absolute_path || location.path + return unless (result = parse_file(file)) + + start_line = location.lineno + result.value.find { |node| node.location.start_line == start_line } + end + end + end +end |