If the buffer is internal, meaning it references memory allocated by the buffer itself.
An internal buffer is not associated with any external memory (e.g. string) or file mapping.
Internal buffers are created using ::new and is the default when the requested size is less than the IO::Buffer::PAGE_SIZE and it was not requested to be mapped on creation.
Internal buffers can be resized, and such an operation will typically invalidate all slices, but not always.
If the buffer is shared, meaning it references memory that can be shared with other processes (and thus might change without being modified locally).
# Create a test file: File.write('test.txt', 'test') # Create a shared mapping from the given file, the file must be opened in # read-write mode unless we also specify IO::Buffer::READONLY: buffer = IO::Buffer.map(File.open('test.txt', 'r+'), nil, 0) # => #<IO::Buffer 0x00007f1bffd5e000+4 EXTERNAL MAPPED SHARED> # Write to the buffer, which will modify the mapped file: buffer.set_string('b', 0) # => 1 # The file itself is modified: File.read('test.txt') # => "best"
If the buffer is read only, meaning the buffer cannot be modified using set_value, set_string or copy and similar.
Frozen strings and read-only files create read-only buffers.
Fill buffer with value, starting with offset and going for length bytes.
buffer = IO::Buffer.for('test').dup # => # <IO::Buffer 0x00007fca40087c38+4 INTERNAL> # 0x00000000 74 65 73 74 test buffer.clear # => # <IO::Buffer 0x00007fca40087c38+4 INTERNAL> # 0x00000000 00 00 00 00 .... buf.clear(1) # fill with 1 # => # <IO::Buffer 0x00007fca40087c38+4 INTERNAL> # 0x00000000 01 01 01 01 .... buffer.clear(2, 1, 2) # fill with 2, starting from offset 1, for 2 bytes # => # <IO::Buffer 0x00007fca40087c38+4 INTERNAL> # 0x00000000 01 02 02 01 .... buffer.clear(2, 1) # fill with 2, starting from offset 1 # => # <IO::Buffer 0x00007fca40087c38+4 INTERNAL> # 0x00000000 01 02 02 02 ....
Efficiently copy from a source IO::Buffer into the buffer, at offset using memmove. For copying String instances, see set_string.
buffer = IO::Buffer.new(32) # => # #<IO::Buffer 0x0000555f5ca22520+32 INTERNAL> # 0x00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ # 0x00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ * buffer.copy(IO::Buffer.for("test"), 8) # => 4 -- size of buffer copied buffer # => # #<IO::Buffer 0x0000555f5cf8fe40+32 INTERNAL> # 0x00000000 00 00 00 00 00 00 00 00 74 65 73 74 00 00 00 00 ........test.... # 0x00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ *
copy can be used to put buffer into strings associated with buffer:
string = "data: " # => "data: " buffer = IO::Buffer.for(string) do |buffer| buffer.copy(IO::Buffer.for("test"), 5) end # => 4 string # => "data:test"
Attempt to copy into a read-only buffer will fail:
File.write('test.txt', 'test') buffer = IO::Buffer.map(File.open('test.txt'), nil, 0, IO::Buffer::READONLY) buffer.copy(IO::Buffer.for("test"), 8) # in `copy': Buffer is not writable! (IO::Buffer::AccessError)
See ::map for details of creation of mutable file mappings, this will work:
buffer = IO::Buffer.map(File.open('test.txt', 'r+')) buffer.copy(IO::Buffer.for("boom"), 0) # => 4 File.read('test.txt') # => "boom"
Attempt to copy the buffer which will need place outside of buffer’s bounds will fail:
buffer = IO::Buffer.new(2) buffer.copy(IO::Buffer.for('test'), 0) # in `copy': Specified offset+length is bigger than the buffer size! (ArgumentError)
It is safe to copy between memory regions that overlaps each other. In such case, the data is copied as if the data was first copied from the source buffer to a temporary buffer, and then copied from the temporary buffer to the destination buffer.
buffer = IO::Buffer.new(10) buffer.set_string("0123456789") buffer.copy(buffer, 3, 7) # => 7 buffer # => # #<IO::Buffer 0x000056494f8ce440+10 INTERNAL> # 0x00000000 30 31 32 30 31 32 33 34 35 36 0120123456
Returns the instruction sequence as a String in human readable form.
puts RubyVM::InstructionSequence.compile('1 + 2').disasm
Produces:
== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>========== 0000 trace 1 ( 1) 0002 putobject 1 0004 putobject 2 0006 opt_plus <ic:1> 0008 leave
Returns the path of this instruction sequence.
<compiled> if the iseq was evaluated from a string.
For example, using irb:
iseq = RubyVM::InstructionSequence.compile('num = 1 + 2') #=> <RubyVM::InstructionSequence:<compiled>@<compiled>> iseq.path #=> "<compiled>"
Using ::compile_file:
# /tmp/method.rb
def hello
puts "hello, world"
end
# in irb
> iseq = RubyVM::InstructionSequence.compile_file('/tmp/method.rb')
> iseq.path #=> /tmp/method.rb
Takes body, a Method or Proc object, and returns a String with the human readable instructions for body.
For a Method object:
# /tmp/method.rb def hello puts "hello, world" end puts RubyVM::InstructionSequence.disasm(method(:hello))
Produces:
== disasm: <RubyVM::InstructionSequence:hello@/tmp/method.rb>============ 0000 trace 8 ( 1) 0002 trace 1 ( 2) 0004 putself 0005 putstring "hello, world" 0007 send :puts, 1, nil, 8, <ic:0> 0013 trace 16 ( 3) 0015 leave ( 2)
For a Proc object:
# /tmp/proc.rb p = proc { num = 1 + 2 } puts RubyVM::InstructionSequence.disasm(p)
Produces:
== disasm: <RubyVM::InstructionSequence:block in <main>@/tmp/proc.rb>=== == catch table | catch type: redo st: 0000 ed: 0012 sp: 0000 cont: 0000 | catch type: next st: 0000 ed: 0012 sp: 0000 cont: 0012 |------------------------------------------------------------------------ local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1] s1) [ 2] num 0000 trace 1 ( 1) 0002 putobject 1 0004 putobject 2 0006 opt_plus <ic:1> 0008 dup 0009 setlocal num, 0 0012 leave
Set path for which this cookie applies
Store session data on the server and close the session storage. For some session storage types, this is a no-op.
Creates a new Net::HTTP object, http, via Net::HTTP.new:
For arguments address and port, see Net::HTTP.new.
For proxy-defining arguments p_addr through p_pass, see Proxy Server.
For argument opts, see below.
With no block given:
Calls http.start with no block (see start), which opens a TCP connection and HTTP session.
Returns http.
The caller should call finish to close the session:
http = Net::HTTP.start(hostname) http.started? # => true http.finish http.started? # => false
With a block given:
Calls http.start with the block (see start), which:
Opens a TCP connection and HTTP session.
Calls the block, which may make any number of requests to the host.
Closes the HTTP session and TCP connection on block exit.
Returns the block’s value object.
Returns object.
Example:
hostname = 'jsonplaceholder.typicode.com' Net::HTTP.start(hostname) do |http| puts http.get('/todos/1').body puts http.get('/todos/2').body end
Output:
{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}
{
"userId": 1,
"id": 2,
"title": "quis ut nam facilis et officia qui",
"completed": false
}
If the last argument given is a hash, it is the opts hash, where each key is a method or accessor to be called, and its value is the value to be set.
The keys may include:
Note: If port is nil and opts[:use_ssl] is a truthy value, the value passed to new is Net::HTTP.https_default_port, not port.
Returns the IP address for the connection.
If the session has not been started, returns the value set by ipaddr=, or nil if it has not been set:
http = Net::HTTP.new(hostname) http.ipaddr # => nil http.ipaddr = '172.67.155.76' http.ipaddr # => "172.67.155.76"
If the session has been started, returns the IP address from the socket:
http = Net::HTTP.new(hostname) http.start http.ipaddr # => "172.67.155.76" http.finish
Sets the IP address for the connection:
http = Net::HTTP.new(hostname) http.ipaddr # => nil http.ipaddr = '172.67.155.76' http.ipaddr # => "172.67.155.76"
The IP address may not be set if the session has been started.
Returns true if the HTTP session has been started:
http = Net::HTTP.new(hostname) http.started? # => false http.start http.started? # => true http.finish # => nil http.started? # => false Net::HTTP.start(hostname) do |http| http.started? end # => true http.started? # => false
Starts an HTTP session.
Without a block, returns self:
http = Net::HTTP.new(hostname) # => #<Net::HTTP jsonplaceholder.typicode.com:80 open=false> http.start # => #<Net::HTTP jsonplaceholder.typicode.com:80 open=true> http.started? # => true http.finish
With a block, calls the block with self, finishes the session when the block exits, and returns the block’s value:
http.start do |http| http end # => #<Net::HTTP jsonplaceholder.typicode.com:80 open=false> http.started? # => false
Sends a PATCH request to the server; returns an instance of a subclass of Net::HTTPResponse.
The request is based on the Net::HTTP::Patch object created from string path, string data, and initial headers hash initheader.
With a block given, calls the block with the response body:
data = '{"userId": 1, "id": 1, "title": "delectus aut autem", "completed": false}' http = Net::HTTP.new(hostname) http.patch('/todos/1', data) do |res| p res end # => #<Net::HTTPOK 200 OK readbody=true>
Output:
"{\n \"userId\": 1,\n \"id\": 1,\n \"title\": \"delectus aut autem\",\n \"completed\": false,\n \"{\\\"userId\\\": 1, \\\"id\\\": 1, \\\"title\\\": \\\"delectus aut autem\\\", \\\"completed\\\": false}\": \"\"\n}"
With no block given, simply returns the response object:
http.patch('/todos/1', data) # => #<Net::HTTPCreated 201 Created readbody=true>
Sends a PROPFIND request to the server; returns an instance of a subclass of Net::HTTPResponse.
The request is based on the Net::HTTP::Propfind object created from string path, string body, and initial headers hash initheader.
data = '{"userId": 1, "id": 1, "title": "delectus aut autem", "completed": false}' http = Net::HTTP.new(hostname) http.propfind('/todos/1', data)
Sends a COPY request to the server; returns an instance of a subclass of Net::HTTPResponse.
The request is based on the Net::HTTP::Copy object created from string path and initial headers hash initheader.
http = Net::HTTP.new(hostname) http.copy('/todos/1')
Creates a new Net::HTTP object, http, via Net::HTTP.new:
For arguments address and port, see Net::HTTP.new.
For proxy-defining arguments p_addr through p_pass, see Proxy Server.
For argument opts, see below.
With no block given:
Calls http.start with no block (see start), which opens a TCP connection and HTTP session.
Returns http.
The caller should call finish to close the session:
http = Net::HTTP.start(hostname) http.started? # => true http.finish http.started? # => false
With a block given:
Calls http.start with the block (see start), which:
Opens a TCP connection and HTTP session.
Calls the block, which may make any number of requests to the host.
Closes the HTTP session and TCP connection on block exit.
Returns the block’s value object.
Returns object.
Example:
hostname = 'jsonplaceholder.typicode.com' Net::HTTP.start(hostname) do |http| puts http.get('/todos/1').body puts http.get('/todos/2').body end
Output:
{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}
{
"userId": 1,
"id": 2,
"title": "quis ut nam facilis et officia qui",
"completed": false
}
If the last argument given is a hash, it is the opts hash, where each key is a method or accessor to be called, and its value is the value to be set.
The keys may include:
Note: If port is nil and opts[:use_ssl] is a truthy value, the value passed to new is Net::HTTP.https_default_port, not port.
Returns the IP address for the connection.
If the session has not been started, returns the value set by ipaddr=, or nil if it has not been set:
http = Net::HTTP.new(hostname) http.ipaddr # => nil http.ipaddr = '172.67.155.76' http.ipaddr # => "172.67.155.76"
If the session has been started, returns the IP address from the socket:
http = Net::HTTP.new(hostname) http.start http.ipaddr # => "172.67.155.76" http.finish
Sets the IP address for the connection:
http = Net::HTTP.new(hostname) http.ipaddr # => nil http.ipaddr = '172.67.155.76' http.ipaddr # => "172.67.155.76"
The IP address may not be set if the session has been started.