Class: Gitgo::Index::ShaFile

Inherits:
Object
  • Object
show all
Defined in:
lib/gitgo/index/sha_file.rb

Overview

ShaFile is a wrapper providing access to a file of H packed shas.

Constant Summary collapse

PACK =

The pack format, optimized for packing multiple shas

"H*"
UNPACK =

The unpacking format

"H40"
ENTRY_SIZE =

The size of an unpacked sha

40
PACKED_ENTRY_SIZE =

The size of a packed sha

20

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file) ⇒ ShaFile

Initializes a new ShaFile with the specified file. The file will be set to binary mode.



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# File 'lib/gitgo/index/sha_file.rb', line 73

def initialize(file)
  file.binmode
  @file = file
end

Instance Attribute Details

#file ⇒ Object (readonly)

The file being wrapped



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# File 'lib/gitgo/index/sha_file.rb', line 69

def file
  @file
end

Class Method Details

.append(path, sha) ⇒ Object

Opens the file and appends the sha. Multiple shas may be appended at once by providing a string of concatenated shas.



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# File 'lib/gitgo/index/sha_file.rb', line 41

def append(path, sha)
  dir = File.dirname(path)
  FileUtils.mkdir_p(dir) unless File.exists?(dir)
  open(path, "a") {|sha_file| sha_file.write(sha) }
end

.open(path, mode = "r") ⇒ Object

Opens and returns an sha file in the specified mode. If a block is given the file is yielded to it and closed afterwards; in this case the return of open is the block result.



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# File 'lib/gitgo/index/sha_file.rb', line 13

def open(path, mode="r")
  sha_file = new(File.open(path, mode))
  
  return sha_file unless block_given?

  begin
    yield(sha_file)
  ensure
    sha_file.close
  end
end

.read(path) ⇒ Object

Reads the file and returns an array of shas.



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# File 'lib/gitgo/index/sha_file.rb', line 26

def read(path)
  open(path) {|sha_file| sha_file.read(nil) }
end

.rm(path, *shas) ⇒ Object

Opens the file and removes the shas.



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# File 'lib/gitgo/index/sha_file.rb', line 48

def rm(path, *shas)
  return unless File.exists?(path)
  
  current = read(path)
  write(path, (current-shas).join)
end

.write(path, sha) ⇒ Object

Opens the file and writes the sha; previous contents are replaced. Multiple shas may be written at once by providing a string of concatenated shas.



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# File 'lib/gitgo/index/sha_file.rb', line 33

def write(path, sha)
  dir = File.dirname(path)
  FileUtils.mkdir_p(dir) unless File.exists?(dir)
  open(path, "w") {|sha_file| sha_file.write(sha) }
end

Instance Method Details

#append(sha) ⇒ Object

Appends the sha to the file. Multiple shas may be appended at once by providing a string of concatenated shas.



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# File 'lib/gitgo/index/sha_file.rb', line 128

def append(sha)
  file.pos = file.size
  write(sha)
  self
end

#close ⇒ Object

Closes file



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# File 'lib/gitgo/index/sha_file.rb', line 79

def close
  file.close
end

#current ⇒ Object

The index of the current entry.



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# File 'lib/gitgo/index/sha_file.rb', line 84

def current
  file.pos / PACKED_ENTRY_SIZE
end

#read(n = 10, start = 0) ⇒ Object

Reads n entries from the start index and returns them as an array. Nil n will read all remaining entries and nil start will read from the current index.



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# File 'lib/gitgo/index/sha_file.rb', line 91

def read(n=10, start=0)
  if start
    start_pos = start * PACKED_ENTRY_SIZE 
    file.pos = start_pos
  end
  
  str = file.read(n.nil? ? nil : n * PACKED_ENTRY_SIZE).to_s
  unless str.length % PACKED_ENTRY_SIZE == 0
    raise "invalid packed sha length: #{str.length}"
  end
  entries = str.unpack(UNPACK * (str.length / PACKED_ENTRY_SIZE))

  # clear out all missing entries, which will be empty
  while last = entries.last
    if last.empty?
      entries.pop
    else
      break
    end
  end
  
  entries
end

#write(sha) ⇒ Object

Writes the sha to the file at the current index. Multiple shas may be written at once by providing a string of concatenated shas.



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# File 'lib/gitgo/index/sha_file.rb', line 117

def write(sha)
  unless sha.length % ENTRY_SIZE == 0
    raise "invalid sha length: #{sha.length}"
  end
  
  file.write [sha].pack(PACK)
  self
end