Class: Gel::Pinboard

Inherits:
Object
  • Object
show all
Defined in:
lib/gel/pinboard.rb

Overview

For each URI, this stores:

* the current etag
* an external freshness token
* a stale flag

Constant Summary collapse

UPDATE_CONCURRENCY = 
8

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(root, httpool: Gel::Httpool.new, work_pool: nil) ⇒ Pinboard

Returns a new instance of Pinboard.



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# File 'lib/gel/pinboard.rb', line 16

def initialize(root, httpool: Gel::Httpool.new, work_pool: nil)
  @root = root
  @httpool = httpool

  @db = Gel::DB.new(root, "pins")
  @files = {}
  @waiting = Hash.new { |h, k| h[k] = [] }

  @work_pool = work_pool || Gel::WorkPool.new(UPDATE_CONCURRENCY, name: "gel-pinboard")
  @monitor = Monitor.new
end

Instance Attribute Details

#root ⇒ Object (readonly)

Returns the value of attribute root.



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# File 'lib/gel/pinboard.rb', line 15

def root
  @root
end

Instance Method Details

#add(uri, token: nil) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 85

def add(uri, token: nil)
  @db[uri.to_s] ||= {
    etag: nil,
    token: token,
    stale: true,
  }
end

#async_file(uri, token: nil, tail: true, only_updated: false, error: nil) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 43

def async_file(uri, token: nil, tail: true, only_updated: false, error: nil)
  file_to_yield = nil

  @monitor.synchronize do
    already_done = @files.key?(uri) && @files[uri].done?

    if !already_done && stale(uri, token)
      add uri, token: token

      already_queued = @files.key?(uri)
      tail_file = @files[uri] ||= Gel::TailFile.new(uri, self, httpool: @httpool)

      unless already_queued
        @work_pool.queue(uri.path) do
          begin
            tail_file.update(force_reset: !tail)
          rescue Exception => ex
            if error
              error.call(ex)
            else
              raise
            end
          end
        end
        @work_pool.start
      end

      @waiting[uri] << lambda do |f, changed|
        yield f if changed || !only_updated
      end
    elsif !only_updated
      file_to_yield = filename(uri)
    end
  end

  if file_to_yield
    File.open(file_to_yield, "r") do |f|
      yield f
    end
  end
end

#etag(uri) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 97

def etag(uri)
  read(uri)[:etag]
end

#file(uri, token: nil, tail: true) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 28

def file(uri, token: nil, tail: true)
  @monitor.synchronize do
    add uri, token: token

    tail_file = Gel::TailFile.new(uri, self, httpool: @httpool)
    tail_file.update(force_reset: !tail) if stale(uri, token)
  end

  if block_given?
    File.open(filename(uri), "r") do |f|
      yield f
    end
  end
end

#filename(uri) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 93

def filename(uri)
  File.expand_path(mangle_uri(uri), @root)
end

#read(uri) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 113

def read(uri)
  @db[uri.to_s]
end

#stale(uri, token) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 101

def stale(uri, token)
  if h = read(uri)
    if token && h[:token] == token || token == false
      return h[:stale]
    end

    @db[uri.to_s] = h.merge(token: token, stale: true)
  end

  true
end

#updated(uri, etag, changed = true) ⇒ Object 



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# File 'lib/gel/pinboard.rb', line 117

def updated(uri, etag, changed = true)
  blocks = nil
  @monitor.synchronize do
    @db[uri.to_s] = read(uri).merge(etag: etag, stale: false)

    blocks = @waiting.delete(uri)
  end

  return unless blocks && blocks.any?

  File.open(filename(uri), "r") do |f|
    blocks.each do |block|
      f.rewind
      block.call(f, changed)
    end
  end
end