Class: Opal::SourceMap::File

Inherits:
Object
  • Object
show all
Includes:
Map
Defined in:
opal/lib/opal/source_map/file.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Map

#as_json, #to_data_uri_comment, #to_h, #to_json, #to_s

Constructor Details

#initialize(fragments, file, source) ⇒ File

Returns a new instance of File.


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# File 'opal/lib/opal/source_map/file.rb', line 10

def initialize(fragments, file, source)
  @fragments = fragments
  @file = file
  @source = source
  @names_map = Hash.new { |hash, name| hash[name] = hash.size }
  @absolute_mappings = nil
end

Instance Attribute Details

#fileObject (readonly)

Returns the value of attribute file.


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# File 'opal/lib/opal/source_map/file.rb', line 7

def file
  @file
end

#fragmentsObject (readonly)

Returns the value of attribute fragments.


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# File 'opal/lib/opal/source_map/file.rb', line 6

def fragments
  @fragments
end

#sourceObject (readonly)

Returns the value of attribute source.


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# File 'opal/lib/opal/source_map/file.rb', line 8

def source
  @source
end

Instance Method Details

#absolute_mappingsObject

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.


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# File 'opal/lib/opal/source_map/file.rb', line 157

def absolute_mappings
  @absolute_mappings ||= begin
    mappings = []

    .each do |raw_segments|
      generated_column = 0
      segments = []
      raw_segments.each do |(generated_code, fragment)|
        if fragment.line && fragment.column
          segments << segment_from_fragment(fragment, generated_column)
        end
        generated_column += generated_code.size
      end
      mappings << segments
    end

    mappings
  end
end

#generated_codeObject


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# File 'opal/lib/opal/source_map/file.rb', line 18

def generated_code
  @generated_code ||= @fragments.map(&:code).join
end

#map(source_root: '') ⇒ Object

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.


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# File 'opal/lib/opal/source_map/file.rb', line 47

def map(source_root: '')
  {
    version: 3,
    # file: "out.js", # This is optional
    sourceRoot: source_root,
    sources: [file],
    sourcesContent: [source.force_encoding('UTF-8')],
    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

#namesObject


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# File 'opal/lib/opal/source_map/file.rb', line 61

def names
  @names ||= begin
    absolute_mappings # let the processing happen
    @names_map.to_a.sort_by { |_, index| index }.map { |name, _| name }
  end
end

#relative_mappingsObject


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# File 'opal/lib/opal/source_map/file.rb', line 123

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

#segment_from_fragment(fragment, generated_column) ⇒ Object

The fields in each segment are:

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.


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# File 'opal/lib/opal/source_map/file.rb', line 99

def segment_from_fragment(fragment, generated_column)
  source_index     = 0                          # always 0, we're dealing with a single file
  original_line    = fragment.line - 1          # fragments have 1-based lines
  original_column  = fragment.column            # 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