Initial commit
This commit is contained in:
NI
146
application/rw/fetch.go
Normal file
146
application/rw/fetch.go
Normal file
@@ -0,0 +1,146 @@
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// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package rw
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import "errors"
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// Errors
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var (
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ErrFetchReaderNotEnoughBuffer = errors.New(
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"Not enough buffer")
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)
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// FetchReaderFetcher generates data for SourceReader
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type FetchReaderFetcher func() ([]byte, error)
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// FetchReader read from the source and increase your lifespan if used correctly
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type FetchReader struct {
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source FetchReaderFetcher // Source data fetcher
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data []byte // Fetched source data
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dataUsed int // Used source data
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}
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// Fetch fetchs
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type Fetch func(n int) ([]byte, error)
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// FetchOneByte fetchs one byte from the Fetch, or return an error when it fails
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func FetchOneByte(f Fetch) ([]byte, error) {
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for {
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d, dErr := f(1)
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if dErr != nil {
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return nil, dErr
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}
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if len(d) <= 0 {
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continue
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}
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return d, nil
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}
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}
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// NewFetchReader creates a new FetchReader
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func NewFetchReader(g FetchReaderFetcher) FetchReader {
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return FetchReader{
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source: g,
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data: nil,
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dataUsed: 0,
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}
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}
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func (r FetchReader) dataRemain() int {
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return len(r.data) - r.dataUsed
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}
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// Remain Returns how many bytes is waiting to be readed
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func (r *FetchReader) Remain() int {
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return r.dataRemain()
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}
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// Export directly exports from buffer, never read from source
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//
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// Params:
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// - n: Exact amount of bytes to fetch (0 to n, n included). If number n is
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// unreachable, an error will be returned, and no internal status will
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// be changed
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//
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// Returns:
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// - Fetched data
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// - Read error
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func (r *FetchReader) Export(n int) ([]byte, error) {
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remain := r.dataRemain()
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if n > remain {
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return nil, ErrFetchReaderNotEnoughBuffer
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}
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newUsed := r.dataUsed + n
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data := r.data[r.dataUsed:newUsed]
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r.dataUsed = newUsed
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return data, nil
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}
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// Fetch fetchs data from the source
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//
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// Params:
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// - n: Max bytes to fetch (0 to n, n included)
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//
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// Returns:
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// - Fetched data
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// - Read error
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func (r *FetchReader) Fetch(n int) ([]byte, error) {
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remain := r.dataRemain()
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if remain <= 0 {
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data, dataFetchErr := r.source()
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if dataFetchErr != nil {
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return nil, dataFetchErr
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}
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r.data = data
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r.dataUsed = 0
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remain = r.dataRemain()
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}
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if n > remain {
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n = remain
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}
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newUsed := r.dataUsed + n
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data := r.data[r.dataUsed:newUsed]
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r.dataUsed = newUsed
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return data, nil
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}
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// Read implements io.Read
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func (r *FetchReader) Read(b []byte) (int, error) {
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d, dErr := r.Fetch(len(b))
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if dErr != nil {
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return 0, dErr
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}
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return copy(b, d), nil
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}
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59
application/rw/fetch_test.go
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59
application/rw/fetch_test.go
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@@ -0,0 +1,59 @@
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// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package rw
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import (
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"bytes"
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"io"
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"testing"
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)
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func testDummyFetchGen(data []byte) FetchReaderFetcher {
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current := 0
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return func() ([]byte, error) {
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if current >= len(data) {
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return nil, io.EOF
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}
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oldCurrent := current
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current = oldCurrent + 1
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return data[oldCurrent:current], nil
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}
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}
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func TestFetchReader(t *testing.T) {
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r := NewFetchReader(testDummyFetchGen([]byte("Hello World")))
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b := make([]byte, 11)
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_, rErr := io.ReadFull(&r, b)
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if rErr != nil {
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t.Error("Failed to read due to error:", rErr)
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return
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}
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if !bytes.Equal(b, []byte("Hello World")) {
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t.Errorf("Expecting data to be %s, got %s instead",
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[]byte("Hello World"), b)
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return
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}
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}
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130
application/rw/limited.go
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130
application/rw/limited.go
Normal file
@@ -0,0 +1,130 @@
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// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package rw
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import (
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"errors"
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"io"
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)
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// Errors
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var (
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ErrReadUntilCompletedBufferFull = errors.New(
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"Cannot read more, not enough data buffer")
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)
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// LimitedReader reads only n bytes of data
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type LimitedReader struct {
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r *FetchReader
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n int
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}
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// ReadUntilCompleted read until the reader is completed
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func ReadUntilCompleted(r *LimitedReader, b []byte) (int, error) {
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bCur := 0
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bLen := len(b)
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for !r.Completed() {
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if bCur >= bLen {
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return bCur, ErrReadUntilCompletedBufferFull
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}
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rLen, rErr := r.Read(b[bCur:])
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if rErr != nil {
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return bCur + rLen, rErr
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}
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bCur += rLen
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}
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return bCur, nil
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}
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// NewLimitedReader creates a new LimitedReader
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func NewLimitedReader(r *FetchReader, n int) LimitedReader {
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return LimitedReader{
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r: r,
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n: n,
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}
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}
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// Buffered exports the internal buffer
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func (l *LimitedReader) Buffered() ([]byte, error) {
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return l.Fetch(l.Remains())
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}
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// Fetch fetchs max n bytes from buffer
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func (l *LimitedReader) Fetch(n int) ([]byte, error) {
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if l.Completed() {
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return nil, io.EOF
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}
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if n > l.Remains() {
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n = l.Remains()
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}
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exported, eErr := l.r.Fetch(n)
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l.n -= len(exported)
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return exported, eErr
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}
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// Read read from the LimitedReader
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func (l *LimitedReader) Read(b []byte) (int, error) {
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if l.Completed() {
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return 0, io.EOF
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}
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toRead := len(b)
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if toRead > l.Remains() {
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toRead = l.Remains()
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}
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rLen, rErr := l.r.Read(b[:toRead])
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l.n -= rLen
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return rLen, rErr
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}
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// Ditch ditchs all remaining data. Data will be written and overwritten to
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// the given buf when ditching
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func (l *LimitedReader) Ditch(buf []byte) error {
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for !l.Completed() {
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_, rErr := l.Read(buf)
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if rErr != nil {
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return rErr
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}
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}
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return nil
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}
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// Remains returns how many bytes is waiting to be read
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func (l LimitedReader) Remains() int {
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return l.n
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}
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// Completed returns whether or not current reader is completed
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func (l LimitedReader) Completed() bool {
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return l.n <= 0
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}
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41
application/rw/rw.go
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41
application/rw/rw.go
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@@ -0,0 +1,41 @@
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// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package rw
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// ReaderFunc function of io.Reader
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type ReaderFunc func(b []byte) (int, error)
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// ReadFull Read until given b is fully loaded
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func ReadFull(r ReaderFunc, b []byte) (int, error) {
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bLen := len(b)
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readed := 0
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for {
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rLen, rErr := r(b[readed:])
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readed += rLen
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if rErr != nil {
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return readed, rErr
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}
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if readed >= bLen {
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return readed, nil
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}
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}
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}
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