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Class: Bundler::CompactIndexClient::CacheFile

Relationships & Source Files
Namespace Children
Exceptions:
ClosedError, DigestMismatchError, Error
Inherits: Object
Defined in: lib/bundler/compact_index_client/cache_file.rb

Overview

write cache files in a way that is robust to concurrent modifications if digests are given, the checksums will be verified

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(original_path, &block) ⇒ CacheFile

[ GitHub ] 

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 49



def initialize(original_path, &block)
  @original_path = original_path
  @perm = original_path.file? ? original_path.stat.mode : DEFAULT_FILE_MODE
  @path = original_path.sub(/$/, ".#{$$}.tmp")
  return unless block_given?
  begin
    yield self
  ensure
    close
  end
end


  







Class Method Details



  

    .copy(path, &block)  
  



  

    

Initialize with a copy of the original file, then yield the instance.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 24



def self.copy(path, &block)
  new(path) do |file|
    file.initialize_digests

    SharedHelpers.filesystem_access(path, :read) do
      path.open("rb") do |s|
        file.open {|f| IO.copy_stream(s, f) }
      end
    end

    yield file
  end
end


  








  

    .write(path, data, digests = nil)  
  



  

    

Write data to a temp file, then replace the original file with it verifying the digests if given.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 39



def self.write(path, data, digests = nil)
  return unless data
  new(path) do |file|
    file.digests = digests
    file.write(data)
  end
end


  







Instance Attribute Details



  

    #digests=(expected_digests)   (rw)
  



  

    

set the digests that will be verified at the end


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 77



def digests=(expected_digests)
  @expected_digests = expected_digests

  if @expected_digests.nil?
    @digests = nil
  elsif @digests
    @digests = @digests.slice(*@expected_digests.keys)
  else
    initialize_digests(@expected_digests.keys)
  end
end


  








  

    #digests?  ⇒ Boolean  (rw)
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 94



def digests?
  @digests&.any?
end


  








  

    #original_path   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 47



attr_reader :original_path, :path


  








  

    #path   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 47



attr_reader :original_path, :path


  







Instance Method Details



  

    #append(data)  
  



  

    

Returns false without appending when no digests since appending is too error prone to do without digests.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 109



def append(data)
  return false unless digests?
  open("a") {|f| f.write data }
  verify && commit
end


  








  

    #close  
  



  

    

Remove the temp file without replacing the original file. The file is permanently closed.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 146



def close
  return if @closed
  FileUtils.remove_file(path) if @path&.file?
  @closed = true
end


  








  

    #commit  
  



  

    

Replace the original file with the temp file without verifying digests. The file is permanently closed.


  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 136



def commit
  raise ClosedError, "Cannot commit closed file" if @closed
  SharedHelpers.filesystem_access(original_path, :write) do
    FileUtils.mv(path, original_path)
  end
  @closed = true
end


  








  

    #commit!  
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 121



def commit!
  verify || raise(DigestMismatchError.new(@base64digests, @expected_digests))
  commit
end


  








  

    #initialize_digests(keys = nil)  
  



  

    

initialize the digests using SUPPORTED_DIGESTS, or a subset based on keys.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 66



def initialize_digests(keys = nil)
  @digests = keys ? SUPPORTED_DIGESTS.slice(*keys) : SUPPORTED_DIGESTS.dup
  @digests.transform_values! {|algo_class| SharedHelpers.digest(algo_class).new }
end


  








  

    #md5  
  



  

    

remove this method when we stop generating md5 digests for legacy etags


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 90



def md5
  @digests && @digests["md5"]
end


  








  

    #open(write_mode = "wb", perm = @perm, &block)  
  



  

    

Open the temp file for writing, reusing original permissions, yielding the IO object.


  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 99



def open(write_mode = "wb", perm = @perm, &block)
  raise ClosedError, "Cannot reopen closed file" if @closed
  SharedHelpers.filesystem_access(path, :write) do
    path.open(write_mode, perm) do |f|
      yield digests? ? Gem::Package::DigestIO.new(f, @digests) : f
    end
  end
end


  








  

    #reset_digests  
  



  

    

reset the digests so they don’t contain any previously read data


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 72



def reset_digests
  @digests&.each_value(&:reset)
end


  








  

    #size  
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 61



def size
  path.size
end


  








  

    #verify  
  



  

    

Verify the digests, returning true on match, false on mismatch.


  



  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 127



def verify
  return true unless @expected_digests && digests?
  @base64digests = @digests.transform_values!(&:base64digest)
  @digests = nil
  @base64digests.all? {|algo, digest| @expected_digests[algo] == digest }
end


  








  

    #write(data)  
  

  [ GitHub ]


  

  


# File 'lib/bundler/compact_index_client/cache_file.rb', line 115



def write(data)
  reset_digests
  open {|f| f.write data }
  commit!
end