Xuanwo commented on code in PR #4886: URL: https://github.com/apache/opendal/pull/4886#discussion_r1676148068
########## bindings/go/reader.go: ########## @@ -0,0 +1,299 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package opendal + +import ( + "context" + "io" + "unsafe" + + "github.com/jupiterrider/ffi" + "golang.org/x/sys/unix" +) + +// Read reads the entire contents of the file at the specified path into a byte slice. +// +// This function is a wrapper around the C-binding function `opendal_operator_read`. +// +// # Parameters +// +// - path: The path of the file to read. +// +// # Returns +// +// - []byte: The contents of the file as a byte slice. +// - error: An error if the read operation fails, or nil if successful. +// +// # Notes +// +// - This implementation does not support the `read_with` functionality. +// - Read allocates a new byte slice internally. For more precise memory control +// or lazy reading, consider using the Reader() method instead. +// +// # Example +// +// func exampleRead(op *opendal.Operator) { +// data, err := op.Read("test") +// if err != nil { +// log.Fatal(err) +// } +// fmt.Printf("Read: %s\n", data) +// } +// +// Note: This example assumes proper error handling and import statements. +func (op *Operator) Read(path string) ([]byte, error) { + read := getFFI[operatorRead](op.ctx, symOperatorRead) + bytes, err := read(op.inner, path) + if err != nil { + return nil, err + } + + data := parseBytes(bytes) + if len(data) > 0 { + free := getFFI[bytesFree](op.ctx, symBytesFree) + free(bytes) + + } + return data, nil +} + +// Reader creates a new Reader for reading the contents of a file at the specified path. +// +// This function is a wrapper around the C-binding function `opendal_operator_reader`. +// +// # Parameters +// +// - path: The path of the file to read. +// +// # Returns +// +// - *OperatorReader: A reader for accessing the file's contents. It implements `io.ReadCloser`. +// - error: An error if the reader creation fails, or nil if successful. +// +// # Notes +// +// - This implementation does not support the `reader_with` functionality. +// - The returned reader allows for more controlled and efficient reading of large files. +// +// # Example +// +// func exampleReader(op *opendal.Operator) { +// r, err := op.Reader("path/to/file") +// if err != nil { +// log.Fatal(err) +// } +// defer r.Close() +// +// size := 1024 // Read 1KB at a time +// buffer := make([]byte, size) +// +// for { +// n, err := r.Read(buffer) +// if err != nil { +// log.Fatal(err) +// } +// fmt.Printf("Read %d bytes: %s\n", n, buffer[:n]) +// } +// } +// +// Note: This example assumes proper error handling and import statements. +func (op *Operator) Reader(path string) (*OperatorReader, error) { + getReader := getFFI[operatorReader](op.ctx, symOperatorReader) + inner, err := getReader(op.inner, path) + if err != nil { + return nil, err + } + reader := &OperatorReader{ + inner: inner, + op: op, + } + return reader, nil +} + +type OperatorReader struct { Review Comment: Can we just use `Reader`? User will use this as `opendal.Reader`, right? ########## bindings/go/README.md: ########## @@ -2,60 +2,123 @@  -opendal-go requires opendal-c to be installed. +opendal-go is a **Native** support Go binding without CGO enabled and is built on top of opendal-c. -```shell -cd bindings/c -make build +```bash +go get opendal.apache.org/go@latest ``` -You will find `libopendal_c.so` under `{root}/target`. +opendal-go requires **libffi** to be installed. -Then, we need to add a `opendal_c.pc` files +## Basic Usage -```pc -libdir=/path/to/opendal/target/debug/ -includedir=/path/to/opendal/bindings/c/include/ +```go +package main -Name: opendal_c -Description: opendal c binding -Version: +import ( + "fmt" + "os" -Libs: -L${libdir} -lopendal_c -Cflags: -I${includedir} -``` + "github.com/yuchanns/opendal-go-services/memory" + "go.yuchanns.xyz/opendal" +) -And set the `PKG_CONFIG_PATH` environment variable to the directory where `opendal_c.pc` is located. +func main() { + // Initialize a new in-memory operator + op, err := opendal.NewOperator(memory.Scheme, opendal.OperatorOptions{}) + if err != nil { + panic(err) + } + defer op.Close() -```shell -export PKG_CONFIG_PATH=/dir/of/opendal_c.pc -``` + // Write data to a file named "test" + err = op.Write("test", []byte("Hello opendal go binding!")) + if err != nil { + panic(err) + } -Then, we can build the go binding. + // Read data from the file "test" + data, err := op.Read("test") + if err != nil { + panic(err) + } + fmt.Printf("Read content: %s\n", data) -```shell -cd bindings/go -go build -tags dynamic . -``` + // List all entries under the root directory "/" + lister, err := op.List("/") + if err != nil { + panic(err) + } + defer lister.Close() -To running the go binding tests, we need to tell the linker where to find the `libopendal_c.so` file. + // Iterate through all entries + for lister.Next() { + entry := lister.Entry() -```shell -expose LD_LIBRARY_PATH=/path/to/opendal/bindings/c/target/debug/ -``` + // Get entry name (not used in this example) + _ = entry.Name() + + // Get metadata for the current entry + meta, _ := op.Stat(entry.Path()) + + // Print file size + fmt.Printf("Size: %d bytes\n", meta.ContentLength()) -Then, we can run the tests. + // Print last modified time + fmt.Printf("Last modified: %s\n", meta.LastModified()) -```shell -go test -tags dynamic . + // Check if the entry is a directory or a file + fmt.Printf("Is directory: %v, Is file: %v\n", meta.IsDir(), meta.IsFile()) + } + + // Check for any errors that occurred during iteration + if err := lister.Error(); err != nil { + panic(err) + } + + // Copy a file + op.Copy("test", "test_copy") + + // Rename a file + op.Rename("test", "test_rename") + + // Delete a file + op.Delete("test_rename") +} ``` -For benchmark +## Run Tests -```shell -go test -bench=. -tags dynamic . +```bash +# Run all tests +CGO_ENABLE=0 go test -v -run TestBehavior Review Comment: `CGO_ENABLE=0`! -- This is an automated message from the Apache Git Service. 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