class PDF::Reader::ObjectCache
A Hash-like object for caching commonly used objects from a PDF file.
This is an internal class, no promises about a stable API.
Constants
- 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
Attributes
Public Class Methods
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# File lib/pdf/reader/object_cache.rb, line 21 def initialize(lru_size = 1000) @objects = {} @lru_cache = Hashery::LRUHash.new(lru_size.to_i) @hits = 0 @misses = 0 end
Public Instance Methods
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# File lib/pdf/reader/object_cache.rb, line 28 def [](key) update_stats(key) @objects[key] || @lru_cache[key] end
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# File lib/pdf/reader/object_cache.rb, line 33 def []=(key, value) if cacheable?(value) @objects[key] = value else @lru_cache[key] = value end end
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# File lib/pdf/reader/object_cache.rb, line 46 def each(&block) @objects.each(&block) @lru_cache.each(&block) end
Also aliased as: each_pair
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# File lib/pdf/reader/object_cache.rb, line 52 def each_key(&block) @objects.each_key(&block) @lru_cache.each_key(&block) end
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# File lib/pdf/reader/object_cache.rb, line 57 def each_value(&block) @objects.each_value(&block) @lru_cache.each_value(&block) end
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# File lib/pdf/reader/object_cache.rb, line 67 def empty? @objects.empty? && @lru_cache.empty? end
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# File lib/pdf/reader/object_cache.rb, line 41 def fetch(key, local_default = nil) update_stats(key) @objects[key] || @lru_cache.fetch(key, local_default) end
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# File lib/pdf/reader/object_cache.rb, line 78 def has_value?(value) @objects.has_value?(value) || @lru_cache.has_value?(value) end
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# File lib/pdf/reader/object_cache.rb, line 71 def include?(key) @objects.include?(key) || @lru_cache.include?(key) end
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# File lib/pdf/reader/object_cache.rb, line 86 def keys @objects.keys + @lru_cache.keys end
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# File lib/pdf/reader/object_cache.rb, line 62 def size @objects.size + @lru_cache.size end
Also aliased as: length
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# File lib/pdf/reader/object_cache.rb, line 82 def to_s "<PDF::Reader::ObjectCache size: #{self.size}>" end
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# File lib/pdf/reader/object_cache.rb, line 90 def values @objects.values + @lru_cache.values end
Private Instance Methods
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# File lib/pdf/reader/object_cache.rb, line 104 def cacheable?(obj) obj.is_a?(Hash) && CACHEABLE_TYPES.include?(obj[:Type]) end
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# File lib/pdf/reader/object_cache.rb, line 96 def update_stats(key) if has_key?(key) @hits += 1 else @misses += 1 end end