class Opal::SourceMap::File
Attributes
Public Class Methods
# File lib/opal/source_map/file.rb, line 10 def initialize(fragments, file, source, generated_code = nil) @fragments = fragments @file = file @source = source @names_map = Hash.new { |hash, name| hash[name] = hash.size } @generated_code = generated_code @absolute_mappings = nil end
Public Instance Methods
The “mappings” data is broken down as follows:
each group representing a line in the generated file is separated by a ”;” each segment is separated by a “,” each segment is made up of 1,4 or 5 variable length fields.
# File lib/opal/source_map/file.rb, line 160 def absolute_mappings @absolute_mappings ||= begin mappings = [] fragments_by_line.each do |raw_segments| generated_column = 0 segments = [] raw_segments.each do |(generated_code, fragment)| unless fragment.is_a?(Opal::Fragment) && fragment.skip_source_map? segments << segment_from_fragment(fragment, generated_column) end generated_column += generated_code.size end mappings << segments end mappings end end
# File lib/opal/source_map/file.rb, line 19 def generated_code @generated_code ||= @fragments.map(&:code).join end
Proposed Format 1: { 2: “version” : 3, 3: “file”: “out.js”, 4: “sourceRoot”: “”, 5: “sources”: [“foo.js”, “bar.js”], 6: “sourcesContent”: [null, null], 7: “names”: [“src”, “maps”, “are”, “fun”], 8: “mappings”: “A,AAAB;;ABCDE;” 9: }
Line 1: The entire file is a single JSON object Line 2: File
version (always the first entry in the object) and must be a
positive integer.
Line 3: An optional name of the generated code that this source map is
associated with.
Line 4: An optional source root, useful for relocating source files on a server
or removing repeated values in the “sources” entry. This value is prepended to the individual entries in the “source” field.
Line 5: A list of original sources used by the “mappings” entry. Line 6: An optional list of source content, useful when the “source” can’t be
hosted. The contents are listed in the same order as the sources in line 5. “null” may be used if some original sources should be retrieved by name.
Line 7: A list of symbol names used by the “mappings” entry. Line 8: A string with the encoded mapping data.
# File lib/opal/source_map/file.rb, line 48 def map(source_root: '') { version: 3, # file: "out.js", # This is optional sourceRoot: source_root, sources: [file], sourcesContent: [source.encoding == Encoding::UTF_8 ? source : source.encode('UTF-8', undef: :replace)], names: names, mappings: Opal::SourceMap::VLQ.encode_mappings(relative_mappings), # x_com_opalrb_original_lines: source.count("\n"), # x_com_opalrb_generated_lines: generated_code.count("\n"), } end
# File lib/opal/source_map/file.rb, line 62 def names @names ||= begin absolute_mappings # let the processing happen @names_map.to_a.sort_by { |_, index| index }.map { |name, _| name } end end
# File lib/opal/source_map/file.rb, line 126 def relative_mappings @relative_mappings ||= begin reference_segment = [0, 0, 0, 0, 0] reference_name_index = 0 absolute_mappings.map do |absolute_mapping| # [generated_column, source_index, original_line, original_column, map_name_index] reference_segment[0] = 0 # reset the generated_column at each new line absolute_mapping.map do |absolute_segment| segment = [] segment[0] = absolute_segment[0] - reference_segment[0] segment[1] = absolute_segment[1] - (reference_segment[1] || 0) segment[2] = absolute_segment[2] - (reference_segment[2] || 0) segment[3] = absolute_segment[3] - (reference_segment[3] || 0) # Since [4] can be nil we need to keep track of it in the reference_segment even if it's nil in absolute_segment if absolute_segment[4] segment[4] = absolute_segment[4].to_int - (reference_segment[4] || reference_name_index).to_int reference_name_index = absolute_segment[4] end reference_segment = absolute_segment segment end end end end
The fields in each segment are:
-
The zero-based starting column of the line in the generated code that the segment represents. If this is the first field of the first segment, or the first segment following a new generated line (“;”), then this field holds the whole base 64 VLQ. Otherwise, this field contains a base 64 VLQ that is relative to the previous occurrence of this field. Note that this is different than the fields below because the previous value is reset after every generated line.
-
If present, an zero-based index into the “sources” list. This field is a base 64 VLQ relative to the previous occurrence of this field, unless this is the first occurrence of this field, in which case the whole value is represented.
-
If present, the zero-based starting line in the original source represented. This field is a base 64 VLQ relative to the previous occurrence of this field, unless this is the first occurrence of this field, in which case the whole value is represented. Always present if there is a source field.
-
If present, the zero-based starting column of the line in the source represented. This field is a base 64 VLQ relative to the previous occurrence of this field, unless this is the first occurrence of this field, in which case the whole value is represented. Always present if there is a source field.
-
If present, the zero-based index into the “names” list associated with this segment. This field is a base 64 VLQ relative to the previous occurrence of this field, unless this is the first occurrence of this field, in which case the whole value is represented.
# File lib/opal/source_map/file.rb, line 100 def segment_from_fragment(fragment, generated_column) source_index = 0 # always 0, we're dealing with a single file original_line = (fragment.line || 0) - 1 # fragments have 1-based lines original_line = 0 if original_line < 0 # line 0 (-1) for fragments in source maps will crash # browsers devtools and the webpack build process original_column = fragment.column || 0 # fragments have 0-based columns if fragment.source_map_name map_name_index = (@names_map[fragment.source_map_name.to_s] ||= @names_map.size) [ generated_column, source_index, original_line, original_column, map_name_index, ] else [ generated_column, source_index, original_line, original_column, ] end end
Private Instance Methods
# File lib/opal/source_map/file.rb, line 182 def fragments_by_line raw_mappings = [[]] fragments.flat_map do |fragment| fragment_code = fragment.code splitter = /\r/.match?(fragment_code) ? /\r?\n/ : "\n" fragment_lines = fragment_code.split(splitter, -1) # a negative limit won't suppress trailing null values fragment_lines.each.with_index do |fragment_line, index| raw_segment = [fragment_line, fragment] if index.zero? && !fragment_line.size.zero? raw_mappings.last << raw_segment elsif index.zero? && fragment_line.size.zero? # noop elsif fragment_line.size.zero? raw_mappings << [] else raw_mappings << [raw_segment] end end end raw_mappings end