class Gio::InputStream

Overview

#GInputStream has functions to read from a stream (g_input_stream_read()), to close a stream (g_input_stream_close()) and to skip some content (g_input_stream_skip()).

To copy the content of an input stream to an output stream without manually handling the reads and writes, use g_output_stream_splice().

See the documentation for #GIOStream for details of thread safety of streaming APIs.

All of these functions have async variants too.

Direct Known Subclasses

Defined in:

lib/gi-crystal/src/auto/gio-2.0/input_stream.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from class GObject::Object

==(other : self) ==, bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void) | Nil data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, hash(hasher) hash, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void) | Nil qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void) | Nil) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void) | Nil steal_data, steal_qdata(quark : UInt32) : Pointer(Void) | Nil steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new
new
, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

cast?(obj : GObject::Object) : self | Nil cast?, compat_control(what : UInt64, data : Pointer(Void) | Nil) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new #

Initialize a new InputStream.


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Class Method Detail

def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.


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Instance Method Detail

def ==(other : self) #
Description copied from class Reference

Returns true if this reference is the same as other. Invokes same?.


def clear_pending : Nil #

Clears the pending flag on stream.


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def close(cancellable : Gio::Cancellable | Nil) : Bool #

Closes the stream, releasing resources related to it.

Once the stream is closed, all other operations will return %G_IO_ERROR_CLOSED. Closing a stream multiple times will not return an error.

Streams will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

Some streams might keep the backing store of the stream (e.g. a file descriptor) open after the stream is closed. See the documentation for the individual stream for details.

On failure the first error that happened will be reported, but the close operation will finish as much as possible. A stream that failed to close will still return %G_IO_ERROR_CLOSED for all operations. Still, it is important to check and report the error to the user.

If cancellable is not nil, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. Cancelling a close will still leave the stream closed, but some streams can use a faster close that doesn't block to e.g. check errors.


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def close_async(io_priority : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Requests an asynchronous closes of the stream, releasing resources related to it. When the operation is finished callback will be called. You can then call g_input_stream_close_finish() to get the result of the operation.

For behaviour details see g_input_stream_close().

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.


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def close_finish(result : Gio::AsyncResult) : Bool #

Finishes closing a stream asynchronously, started from g_input_stream_close_async().


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def has_pending : Bool #

Checks if an input stream has pending actions.


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def hash(hasher) #
Description copied from class Reference

See Object#hash(hasher)


def is_closed : Bool #

Checks if an input stream is closed.


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def read(buffer : Bytes, cancellable : Gio::Cancellable | Nil) : Int64 #

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

If count is zero returns zero and does nothing. A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, the number of bytes read into the buffer is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file. Zero is returned on end of file (or if count is zero), but never otherwise.

The returned buffer is not a nul-terminated string, it can contain nul bytes at any position, and this function doesn't nul-terminate the buffer.

If cancellable is not nil, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error -1 is returned and error is set accordingly.


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def read_all(buffer : Bytes, bytes_read : UInt64, cancellable : Gio::Cancellable | Nil) : Bool #

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

This function is similar to g_input_stream_read(), except it tries to read as many bytes as requested, only stopping on an error or end of stream.

On a successful read of count bytes, or if we reached the end of the stream, true is returned, and bytes_read is set to the number of bytes read into buffer.

If there is an error during the operation false is returned and error is set to indicate the error status.

As a special exception to the normal conventions for functions that use #GError, if this function returns false (and sets error) then bytes_read will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around g_input_stream_read().


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def read_all_async(buffer : Bytes, io_priority : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer.

This is the asynchronous equivalent of g_input_stream_read_all().

Call g_input_stream_read_all_finish() to collect the result.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.


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def read_all_finish(result : Gio::AsyncResult, bytes_read : UInt64) : Bool #

Finishes an asynchronous stream read operation started with g_input_stream_read_all_async().

As a special exception to the normal conventions for functions that use #GError, if this function returns false (and sets error) then bytes_read will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around g_input_stream_read_async().


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def read_async(buffer : Bytes, io_priority : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer. When the operation is finished callback will be called. You can then call g_input_stream_read_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in %G_IO_ERROR_PENDING errors.

A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, the number of bytes read into the buffer will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.


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def read_bytes(count : UInt64, cancellable : Gio::Cancellable | Nil) : GLib::Bytes #

Like g_input_stream_read(), this tries to read count bytes from the stream in a blocking fashion. However, rather than reading into a user-supplied buffer, this will create a new #GBytes containing the data that was read. This may be easier to use from language bindings.

If count is zero, returns a zero-length #GBytes and does nothing. A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, a new #GBytes is returned. It is not an error if the size of this object is not the same as the requested size, as it can happen e.g. near the end of a file. A zero-length #GBytes is returned on end of file (or if count is zero), but never otherwise.

If cancellable is not nil, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error nil is returned and error is set accordingly.


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def read_bytes_async(count : UInt64, io_priority : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Request an asynchronous read of count bytes from the stream into a new #GBytes. When the operation is finished callback will be called. You can then call g_input_stream_read_bytes_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in %G_IO_ERROR_PENDING errors.

A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, the new #GBytes will be passed to the callback. It is not an error if this is smaller than the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.


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def read_bytes_finish(result : Gio::AsyncResult) : GLib::Bytes #

Finishes an asynchronous stream read-into-#GBytes operation.


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def read_finish(result : Gio::AsyncResult) : Int64 #

Finishes an asynchronous stream read operation.


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def set_pending : Bool #

Sets stream to have actions pending. If the pending flag is already set or stream is closed, it will return false and set error.


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def skip(count : UInt64, cancellable : Gio::Cancellable | Nil) : Int64 #

Tries to skip count bytes from the stream. Will block during the operation.

This is identical to g_input_stream_read(), from a behaviour standpoint, but the bytes that are skipped are not returned to the user. Some streams have an implementation that is more efficient than reading the data.

This function is optional for inherited classes, as the default implementation emulates it using read.

If cancellable is not nil, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.


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def skip_async(count : UInt64, io_priority : Int32, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil #

Request an asynchronous skip of count bytes from the stream. When the operation is finished callback will be called. You can then call g_input_stream_skip_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed, and will result in %G_IO_ERROR_PENDING errors.

A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, the number of bytes skipped will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to skip as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is %G_PRIORITY_DEFAULT.

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one, you must override all.


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def skip_finish(result : Gio::AsyncResult) : Int64 #

Finishes a stream skip operation.


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