Class: PDF::Reader::ObjectCache

Inherits:
Object
  • Object
show all
Defined in:
lib/pdf/reader/object_cache.rb

Overview

A Hash-like object for caching commonly used objects from a PDF file.

This is an internal class, no promises about a stable API.

Constant Summary collapse

CACHEABLE_TYPES =

These object types use little memory and are accessed a heap of times as part of random page access, so we’ll cache the unmarshalled objects and avoid lots of repetitive (and expensive) tokenising

[:Catalog, :Page, :Pages]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(lru_size = 1000) ⇒ ObjectCache

Returns a new instance of ObjectCache.



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# File 'lib/pdf/reader/object_cache.rb', line 20

def initialize(lru_size = 1000)
  @objects = {}
  @lru_cache = Hashery::LRUHash.new(lru_size.to_i)
  @hits = 0
  @misses = 0
end

Instance Attribute Details

#hits ⇒ Object (readonly)

Returns the value of attribute hits.



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# File 'lib/pdf/reader/object_cache.rb', line 18

def hits
  @hits
end

#misses ⇒ Object (readonly)

Returns the value of attribute misses.



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# File 'lib/pdf/reader/object_cache.rb', line 18

def misses
  @misses
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 27

def [](key)
  update_stats(key)
  @objects[key] || @lru_cache[key]
end

#[]=(key, value) ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 32

def []=(key, value)
  if cacheable?(value)
    @objects[key] = value
  else
    @lru_cache[key] = value
  end
end

#each(&block) ⇒ Object Also known as: each_pair 



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# File 'lib/pdf/reader/object_cache.rb', line 45

def each(&block)
  @objects.each(&block)
  @lru_cache.each(&block)
end

#each_key(&block) ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 51

def each_key(&block)
  @objects.each_key(&block)
  @lru_cache.each_key(&block)
end

#each_value(&block) ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 56

def each_value(&block)
  @objects.each_value(&block)
  @lru_cache.each_value(&block)
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdf/reader/object_cache.rb', line 66

def empty?
  @objects.empty? && @lru_cache.empty?
end

#fetch(key, local_default = nil) ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 40

def fetch(key, local_default = nil)
  update_stats(key)
  @objects[key] || @lru_cache.fetch(key, local_default)
end

#has_value?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdf/reader/object_cache.rb', line 77

def has_value?(value)
  @objects.has_value?(value) || @lru_cache.has_value?(value)
end

#include?(key) ⇒ Boolean Also known as: has_key?, key?, member?

Returns:

  • (Boolean) 


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# File 'lib/pdf/reader/object_cache.rb', line 70

def include?(key)
  @objects.include?(key) || @lru_cache.include?(key)
end

#keys ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 85

def keys
  @objects.keys + @lru_cache.keys
end

#size ⇒ Object Also known as: length 



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# File 'lib/pdf/reader/object_cache.rb', line 61

def size
  @objects.size + @lru_cache.size
end

#to_s ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 81

def to_s
  "<PDF::Reader::ObjectCache size: #{self.size}>"
end

#values ⇒ Object 



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# File 'lib/pdf/reader/object_cache.rb', line 89

def values
  @objects.values + @lru_cache.values
end