commit 631979886a42bf2dd3cb495b5f027a9fc7352b98 Author: arzumify Date: Fri Oct 25 18:14:53 2024 +0100 Initial commit diff --git a/LICENSE.md b/LICENSE.md new file mode 100644 index 0000000..969dabb --- /dev/null +++ b/LICENSE.md @@ -0,0 +1,157 @@ +# GNU LESSER GENERAL PUBLIC LICENSE + +Version 3, 29 June 2007 + +Copyright (C) 2007 Free Software Foundation, Inc. + + +Everyone is permitted to copy and distribute verbatim copies of this +license document, but changing it is not allowed. + +This version of the GNU Lesser General Public License incorporates the +terms and conditions of version 3 of the GNU General Public License, +supplemented by the additional permissions listed below. + +## 0. Additional Definitions. + +As used herein, "this License" refers to version 3 of the GNU Lesser +General Public License, and the "GNU GPL" refers to version 3 of the +GNU General Public License. + +"The Library" refers to a covered work governed by this License, other +than an Application or a Combined Work as defined below. + +An "Application" is any work that makes use of an interface provided +by the Library, but which is not otherwise based on the Library. +Defining a subclass of a class defined by the Library is deemed a mode +of using an interface provided by the Library. + +A "Combined Work" is a work produced by combining or linking an +Application with the Library. The particular version of the Library +with which the Combined Work was made is also called the "Linked +Version". + +The "Minimal Corresponding Source" for a Combined Work means the +Corresponding Source for the Combined Work, excluding any source code +for portions of the Combined Work that, considered in isolation, are +based on the Application, and not on the Linked Version. + +The "Corresponding Application Code" for a Combined Work means the +object code and/or source code for the Application, including any data +and utility programs needed for reproducing the Combined Work from the +Application, but excluding the System Libraries of the Combined Work. + +## 1. Exception to Section 3 of the GNU GPL. + +You may convey a covered work under sections 3 and 4 of this License +without being bound by section 3 of the GNU GPL. + +## 2. Conveying Modified Versions. + +If you modify a copy of the Library, and, in your modifications, a +facility refers to a function or data to be supplied by an Application +that uses the facility (other than as an argument passed when the +facility is invoked), then you may convey a copy of the modified +version: + +- a) under this License, provided that you make a good faith effort + to ensure that, in the event an Application does not supply the + function or data, the facility still operates, and performs + whatever part of its purpose remains meaningful, or +- b) under the GNU GPL, with none of the additional permissions of + this License applicable to that copy. + +## 3. Object Code Incorporating Material from Library Header Files. + +The object code form of an Application may incorporate material from a +header file that is part of the Library. You may convey such object +code under terms of your choice, provided that, if the incorporated +material is not limited to numerical parameters, data structure +layouts and accessors, or small macros, inline functions and templates +(ten or fewer lines in length), you do both of the following: + +- a) Give prominent notice with each copy of the object code that + the Library is used in it and that the Library and its use are + covered by this License. +- b) Accompany the object code with a copy of the GNU GPL and this + license document. + +## 4. Combined Works. + +You may convey a Combined Work under terms of your choice that, taken +together, effectively do not restrict modification of the portions of +the Library contained in the Combined Work and reverse engineering for +debugging such modifications, if you also do each of the following: + +- a) Give prominent notice with each copy of the Combined Work that + the Library is used in it and that the Library and its use are + covered by this License. +- b) Accompany the Combined Work with a copy of the GNU GPL and this + license document. +- c) For a Combined Work that displays copyright notices during + execution, include the copyright notice for the Library among + these notices, as well as a reference directing the user to the + copies of the GNU GPL and this license document. +- d) Do one of the following: + - 0) Convey the Minimal Corresponding Source under the terms of + this License, and the Corresponding Application Code in a form + suitable for, and under terms that permit, the user to + recombine or relink the Application with a modified version of + the Linked Version to produce a modified Combined Work, in the + manner specified by section 6 of the GNU GPL for conveying + Corresponding Source. + - 1) Use a suitable shared library mechanism for linking with + the Library. A suitable mechanism is one that (a) uses at run + time a copy of the Library already present on the user's + computer system, and (b) will operate properly with a modified + version of the Library that is interface-compatible with the + Linked Version. +- e) Provide Installation Information, but only if you would + otherwise be required to provide such information under section 6 + of the GNU GPL, and only to the extent that such information is + necessary to install and execute a modified version of the + Combined Work produced by recombining or relinking the Application + with a modified version of the Linked Version. (If you use option + 4d0, the Installation Information must accompany the Minimal + Corresponding Source and Corresponding Application Code. If you + use option 4d1, you must provide the Installation Information in + the manner specified by section 6 of the GNU GPL for conveying + Corresponding Source.) + +## 5. Combined Libraries. + +You may place library facilities that are a work based on the Library +side by side in a single library together with other library +facilities that are not Applications and are not covered by this +License, and convey such a combined library under terms of your +choice, if you do both of the following: + +- a) Accompany the combined library with a copy of the same work + based on the Library, uncombined with any other library + facilities, conveyed under the terms of this License. +- b) Give prominent notice with the combined library that part of it + is a work based on the Library, and explaining where to find the + accompanying uncombined form of the same work. + +## 6. Revised Versions of the GNU Lesser General Public License. + +The Free Software Foundation may publish revised and/or new versions +of the GNU Lesser General Public License from time to time. Such new +versions will be similar in spirit to the present version, but may +differ in detail to address new problems or concerns. + +Each version is given a distinguishing version number. If the Library +as you received it specifies that a certain numbered version of the +GNU Lesser General Public License "or any later version" applies to +it, you have the option of following the terms and conditions either +of that published version or of any later version published by the +Free Software Foundation. If the Library as you received it does not +specify a version number of the GNU Lesser General Public License, you +may choose any version of the GNU Lesser General Public License ever +published by the Free Software Foundation. + +If the Library as you received it specifies that a proxy can decide +whether future versions of the GNU Lesser General Public License shall +apply, that proxy's public statement of acceptance of any version is +permanent authorization for you to choose that version for the +Library. \ No newline at end of file diff --git a/README.md b/README.md new file mode 100644 index 0000000..5cf3c88 --- /dev/null +++ b/README.md @@ -0,0 +1,7 @@ +# jsStreams + +Go library to communicate with the JS Stream API by bridging the JS ReadableStream object to a Go io.ReaderCloser. + +[![Go Report Card](https://goreportcard.com/badge/git.ailur.dev/ailur/jsStreams)](https://goreportcard.com/report/git.ailur.dev/ailur/jsStreams) [![Go Reference](https://pkg.go.dev/badge/git.ailur.dev/ailur/jsStreams.svg)](https://pkg.go.dev/git.ailur.dev/ailur/jsStreams) + +The API is pretty self-explanatory - it provides a function to create an io.ReaderCloser from a JS ReadableStream object. \ No newline at end of file diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..4f06c3f --- /dev/null +++ b/go.mod @@ -0,0 +1,3 @@ +module git.ailur.dev/ailur/jsStreams + +go 1.22 diff --git a/main.go b/main.go new file mode 100644 index 0000000..b6cb099 --- /dev/null +++ b/main.go @@ -0,0 +1,83 @@ +package jsStreams + +import ( + "errors" + "fmt" + "sync" + + "syscall/js" +) + +// ReadableStream implements io.ReaderCloser for a JavaScript ReadableStream. +type ReadableStream struct { + stream js.Value + reader js.Value + lock sync.Mutex +} + +// Read reads up to len(p) bytes into p. It returns the number of bytes read (0 <= n <= len(p)) and any error encountered. +// This implementation of Read does not use scratch space if n < len(p). If some data is available but not len(p) bytes, +// Read conventionally returns what is available instead of waiting for more. Note: Read will block until data is available, +// meaning in a WASM environment, you **must** use a goroutine to call Read. +func (r *ReadableStream) Read(inputBytes []byte) (n int, err error) { + defer func() { + recovered := recover() + if recovered != nil { + err = fmt.Errorf("panic: %v", recovered) + } + }() + + r.lock.Lock() + var waitGroup sync.WaitGroup + waitGroup.Add(1) + + if r.reader.IsUndefined() { + r.reader = r.stream.Call("getReader", map[string]interface{}{"mode": "byob"}) + } + + resultBuffer := js.Global().Get("Uint8Array").New(len(inputBytes)) + readResult := r.reader.Call("read", resultBuffer) + + readResult.Call("then", js.FuncOf(func(this js.Value, args []js.Value) interface{} { + defer waitGroup.Done() + data := args[0].Get("value") + js.CopyBytesToGo(inputBytes, data) + if args[0].Get("done").Bool() { + err = errors.New("EOF") + } + n = data.Length() + return nil + })) + + readResult.Call("catch", js.FuncOf(func(this js.Value, args []js.Value) interface{} { + defer waitGroup.Done() + err = errors.New(args[0].Get("message").String()) + return nil + })) + + waitGroup.Wait() + + return n, err +} + +// Close closes the ReadableStream. If the stream is already closed, Close does nothing. +// If the stream is not yet closed, it is canceled. The reader is closed and the underlying source or pipeline is terminated. +// This method is idempotent, meaning that it can be called multiple times without causing an error. +func (r *ReadableStream) Close() (err error) { + defer func() { + recovered := recover() + if recovered != nil { + err = fmt.Errorf("panic: %v", recovered) + } + }() + + if !r.reader.IsUndefined() { + r.reader.Call("cancel") + } + + return nil +} + +func NewReadableStream(stream js.Value) *ReadableStream { + return &ReadableStream{stream: stream} +}