Class: BuildpackSupport::Cache::CachedFile

Inherits:
Object
  • Object
show all
Defined in:
lib/buildpack_support/cache/cached_file.rb

Overview

Represents a file cached on a filesystem

Note: this class is thread-safe, however access to the cached files is not

Instance Method Summary collapse

Constructor Details

#initialize(cache_root, uri, mutable) ⇒ CachedFile

Creates an instance of the cached file. Files created and expected by this class will all be rooted at cache_root.

Parameters:

  • cache_root (Pathname) —

    the filesystem root for the file created and expected by this class

  • uri (String) —

    a uri which uniquely identifies the file in the cache

  • mutable (Boolean) —

    whether the cached file should be mutable



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# File 'lib/buildpack_support/cache/cached_file.rb', line 33

def initialize(cache_root, uri, mutable)
  key            = URI.escape(uri, ':/')
  @cached        = cache_root + "#{key}.cached"
  @etag          = cache_root + "#{key}.etag"
  @last_modified = cache_root + "#{key}.last_modified"
  @mutable       = mutable

  FileUtils.mkdir_p cache_root if mutable
end

Instance Method Details

#cached(mode_enc, *additional_args) {|file, additional_args| ... } ⇒ Void

Opens the cached file

Parameters:

  • mode_enc (String, integer) —

    the mode to open the file in. Can be a string like “r” or an integer like File::CREAT | File::WRONLY.

  • additional_args (Array) —

    any additional arguments to be passed to the block

Yields:

  • (file, additional_args) —

    the cached file and any additional arguments passed in

Returns:

  • (Void) 


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# File 'lib/buildpack_support/cache/cached_file.rb', line 50

def cached(mode_enc, *additional_args, &block)
  @cached.open(mode_enc) { |f| block.call f, *additional_args }
end

#cached? ⇒ Boolean

Returns whether or not data is cached.

Returns:

  • (Boolean) —

    true if and only if data is cached



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# File 'lib/buildpack_support/cache/cached_file.rb', line 57

def cached?
  @cached.exist?
end

#destroy ⇒ Object

Destroys the cached file



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# File 'lib/buildpack_support/cache/cached_file.rb', line 62

def destroy
  [@cached, @etag, @last_modified].each { |f| f.delete if f.exist? } if @mutable
end

#etag(mode_enc, *additional_args) {|file| ... } ⇒ Void

Opens the etag file

Parameters:

  • mode_enc (String, integer) —

    the mode to open the file in. Can be a string like “r” or an integer like File::CREAT | File::WRONLY.

  • additional_args (Array) —

    any additional arguments to be passed to the block

Yields:

  • (file) —

    the etag file

Returns:

  • (Void) 


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# File 'lib/buildpack_support/cache/cached_file.rb', line 73

def etag(mode_enc, *additional_args, &block)
  @etag.open(mode_enc) { |f| block.call f, *additional_args }
end

#etag? ⇒ Boolean

Returns whether or not an etag is stored.

Returns:

  • (Boolean) —

    true if and only if an etag is stored



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# File 'lib/buildpack_support/cache/cached_file.rb', line 80

def etag?
  @etag.exist?
end

#last_modified(mode_enc, *additional_args) {|file| ... } ⇒ Void

Opens the last modified file

Parameters:

  • mode_enc (String, integer) —

    the mode to open the file in. Can be a string like “r” or an integer like File::CREAT | File::WRONLY.

  • additional_args (Array) —

    any additional arguments to be passed to the block

Yields:

  • (file) —

    the last modified file

Returns:

  • (Void) 


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# File 'lib/buildpack_support/cache/cached_file.rb', line 91

def last_modified(mode_enc, *additional_args, &block)
  @last_modified.open(mode_enc) { |f| block.call f, *additional_args }
end

#last_modified? ⇒ Boolean

Returns whether or not a last modified time stamp is stored.

Returns:

  • (Boolean) —

    true if and only if a last modified time stamp is stored



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# File 'lib/buildpack_support/cache/cached_file.rb', line 98

def last_modified?
  @last_modified.exist?
end