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WIP Add spec for IO::Buffer.map
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‎core/io/buffer/fixtures/big_file.txt‎

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require_relative '../../../spec_helper'
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describe "IO::Buffer.map" do
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after :each do
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@buffer&.free
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@buffer = nil
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@file&.close
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@file = nil
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end
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def open_fixture
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File.open("#{__dir__}/../fixtures/read_text.txt", "r+")
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end
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it "creates a new buffer mapped from a file" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file)
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@buffer.size.should == 9
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@buffer.get_string.should == "abcâdef\n".b
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end
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it "allows to close the file after creating buffer, retaining mapping" do
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file = open_fixture
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@buffer = IO::Buffer.map(file)
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file.close
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@buffer.get_string.should == "abcâdef\n".b
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end
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ruby_version_is ""..."3.3" do
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it "creates a buffer with default state and expected flags" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file)
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@buffer.should_not.internal?
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@buffer.should.mapped?
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@buffer.should.external?
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@buffer.should_not.empty?
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@buffer.should_not.null?
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@buffer.should.shared?
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@buffer.should_not.readonly?
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@buffer.should_not.locked?
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@buffer.should.valid?
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end
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end
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ruby_version_is "3.3" do
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it "creates a buffer with default state and expected flags" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file)
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@buffer.should_not.internal?
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@buffer.should.mapped?
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@buffer.should.external?
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@buffer.should_not.empty?
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@buffer.should_not.null?
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@buffer.should.shared?
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@buffer.should_not.private?
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@buffer.should_not.readonly?
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@buffer.should_not.locked?
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@buffer.should.valid?
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end
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end
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platform_is_not :windows do
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it "is shareable across processes" do
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file_name = tmp("shared_buffer")
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@file = File.open(file_name, "w+")
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@file << "I'm private"
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@file.rewind
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@buffer = IO::Buffer.map(@file)
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IO.popen("-") do |child_pipe|
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if child_pipe
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# Synchronize on child's output.
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child_pipe.readlines.first.chomp.should == @buffer.to_s
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@buffer.get_string.should == "I'm shared!"
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@file.read.should == "I'm shared!"
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else
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@buffer.set_string("I'm shared!")
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puts @buffer
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end
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ensure
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child_pipe&.close
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end
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ensure
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File.unlink(file_name)
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end
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end
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context "with an empty file" do
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ruby_version_is ""..."4.0" do
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it "raises a SystemCallError" do
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@file = File.open("#{__dir__}/../fixtures/empty.txt", "r+")
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-> { IO::Buffer.map(@file) }.should raise_error(SystemCallError)
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end
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end
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ruby_version_is "4.0" do
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it "raises ArgumentError" do
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@file = File.open("#{__dir__}/../fixtures/empty.txt", "r+")
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-> { IO::Buffer.map(@file) }.should raise_error(ArgumentError, "Invalid negative or zero file size!")
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end
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end
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end
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context "with a file opened only for reading" do
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it "raises a SystemCallError if no flags are used" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r")
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-> { IO::Buffer.map(@file) }.should raise_error(SystemCallError)
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end
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end
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context "with size argument" do
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it "limits the buffer to the specified size in bytes, starting from the start of the file" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, 4)
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@buffer.size.should == 4
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@buffer.get_string.should == "abc\xC3".b
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end
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it "maps the whole file if size is nil" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, nil)
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@buffer.size.should == 9
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end
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context "if size is 0" do
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ruby_version_is ""..."4.0" do
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platform_is_not :windows do
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it "raises a SystemCallError" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 0) }.should raise_error(SystemCallError)
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end
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end
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end
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ruby_version_is "4.0" do
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it "raises ArgumentError" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 0) }.should raise_error(ArgumentError, "Size can't be zero!")
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end
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end
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end
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it "raises TypeError if size is not an Integer or nil" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, "10") }.should raise_error(TypeError, "not an Integer")
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-> { IO::Buffer.map(@file, 10.0) }.should raise_error(TypeError, "not an Integer")
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end
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it "raises ArgumentError if size is negative" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, -1) }.should raise_error(ArgumentError, "Size can't be negative!")
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end
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ruby_version_is ""..."4.0" do
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# May or may not cause a crash on access.
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it "is undefined behavior if size is larger than file size"
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end
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ruby_version_is "4.0" do
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it "raises ArgumentError if size is larger than file size" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 8192) }.should raise_error(ArgumentError, "Size can't be larger than file size!")
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end
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end
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end
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context "with size and offset arguments" do
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# Neither Windows nor macOS have clear, stable behavior with non-zero offset.
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# https://bugs.ruby-lang.org/issues/21700
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platform_is :linux do
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context "if offset is an allowed value for system call" do
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it "maps the span specified by size starting from the offset" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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@buffer = IO::Buffer.map(@file, 14, IO::Buffer::PAGE_SIZE)
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@buffer.size.should == 14
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@buffer.get_string(0, 14).should == "rror if size i"
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end
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context "if size is nil" do
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ruby_version_is ""..."4.0" do
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it "maps the rest of the file" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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@buffer = IO::Buffer.map(@file, nil, IO::Buffer::PAGE_SIZE)
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@buffer.get_string(0, 1).should == "r"
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end
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it "incorrectly sets buffer's size to file's full size" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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@buffer = IO::Buffer.map(@file, nil, IO::Buffer::PAGE_SIZE)
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@buffer.size.should == @file.size
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end
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end
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ruby_version_is "4.0" do
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it "maps the rest of the file" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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@buffer = IO::Buffer.map(@file, nil, IO::Buffer::PAGE_SIZE)
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@buffer.get_string(0, 1).should == "r"
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end
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it "sets buffer's size to file's remaining size" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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@buffer = IO::Buffer.map(@file, nil, IO::Buffer::PAGE_SIZE)
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@buffer.size.should == (@file.size - IO::Buffer::PAGE_SIZE)
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end
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end
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end
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end
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end
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it "maps the file from the start if offset is 0" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, 4, 0)
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@buffer.size.should == 4
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@buffer.get_string.should == "abc\xC3".b
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end
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ruby_version_is ""..."4.0" do
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# May or may not cause a crash on access.
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it "is undefined behavior if offset+size is larger than file size"
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end
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ruby_version_is "4.0" do
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it "raises ArgumentError if offset+size is larger than file size" do
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@file = File.open(fixture(__FILE__, "big_file.txt"), "r+")
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-> { IO::Buffer.map(@file, 8192, IO::Buffer::PAGE_SIZE) }.should raise_error(ArgumentError, "Offset too large!")
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end
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end
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it "raises TypeError if offset is not convertible to Integer" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 4, "4096") }.should raise_error(TypeError, /no implicit conversion/)
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-> { IO::Buffer.map(@file, 4, nil) }.should raise_error(TypeError, /no implicit conversion/)
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end
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it "raises a SystemCallError if offset is not an allowed value" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 4, 3) }.should raise_error(SystemCallError)
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end
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ruby_version_is ""..."4.0" do
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it "raises a SystemCallError if offset is negative" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 4, -1) }.should raise_error(SystemCallError)
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end
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end
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ruby_version_is "4.0" do
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it "raises ArgumentError if offset is negative" do
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@file = open_fixture
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-> { IO::Buffer.map(@file, 4, -1) }.should raise_error(ArgumentError, "Offset can't be negative!")
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end
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end
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end
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context "with flags argument" do
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context "when READONLY flag is specified" do
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it "sets readonly flag on the buffer, allowing only reads" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::READONLY)
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@buffer.should.readonly?
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@buffer.get_string.should == "abc\xC3\xA2def\n".b
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end
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it "allows mapping read-only files" do
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@file = File.open("#{__dir__}/../fixtures/read_text.txt", "r")
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::READONLY)
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@buffer.should.readonly?
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@buffer.get_string.should == "abc\xC3\xA2def\n".b
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end
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it "causes IO::Buffer::AccessError on write" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::READONLY)
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-> { @buffer.set_string("test") }.should raise_error(IO::Buffer::AccessError, "Buffer is not writable!")
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end
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end
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ruby_version_is "3.3" do
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context "when PRIVATE is specified" do
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it "sets private flag on the buffer, making it freely modifiable" do
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@file = open_fixture
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::PRIVATE)
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@buffer.should.private?
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@buffer.should_not.shared?
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@buffer.should_not.external?
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@buffer.get_string.should == "abc\xC3\xA2def\n".b
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@buffer.set_string("test12345")
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@buffer.get_string.should == "test12345".b
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@file.read.should == "abcâdef\n"
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end
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it "allows mapping read-only files and modifying the buffer" do
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@file = File.open("#{__dir__}/../fixtures/read_text.txt", "r")
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::PRIVATE)
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@buffer.should.private?
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@buffer.should_not.shared?
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@buffer.should_not.external?
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@buffer.get_string.should == "abc\xC3\xA2def\n".b
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@buffer.set_string("test12345")
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@buffer.get_string.should == "test12345".b
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@file.read.should == "abcâdef\n"
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end
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platform_is_not :windows do
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it "is not shared across processes" do
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file_name = tmp("shared_buffer")
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@file = File.open(file_name, "w+")
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@file << "I'm private"
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@file.rewind
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@buffer = IO::Buffer.map(@file, nil, 0, IO::Buffer::PRIVATE)
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IO.popen("-") do |child_pipe|
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if child_pipe
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# Synchronize on child's output.
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child_pipe.readlines.first.chomp.should == @buffer.to_s
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@buffer.get_string.should == "I'm private"
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@file.read.should == "I'm private"
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else
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@buffer.set_string("I'm shared!")
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puts @buffer
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end
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ensure
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child_pipe&.close
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end
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ensure
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File.unlink(file_name)
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end
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end
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end
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end
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end
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end

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