httpfs.go

Documentation: golang.org/x/tools/godoc/vfs/httpfs

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package httpfs implements http.FileSystem using a godoc vfs.FileSystem.
     6  package httpfs // import "golang.org/x/tools/godoc/vfs/httpfs"
     7  
     8  import (
     9  	"fmt"
    10  	"io"
    11  	"net/http"
    12  	"os"
    13  
    14  	"golang.org/x/tools/godoc/vfs"
    15  )
    16  
    17  func New(fs vfs.FileSystem) http.FileSystem {
    18  	return &httpFS{fs}
    19  }
    20  
    21  type httpFS struct {
    22  	fs vfs.FileSystem
    23  }
    24  
    25  func (h *httpFS) Open(name string) (http.File, error) {
    26  	fi, err := h.fs.Stat(name)
    27  	if err != nil {
    28  		return nil, err
    29  	}
    30  	if fi.IsDir() {
    31  		return &httpDir{h.fs, name, nil}, nil
    32  	}
    33  	f, err := h.fs.Open(name)
    34  	if err != nil {
    35  		return nil, err
    36  	}
    37  	return &httpFile{h.fs, f, name}, nil
    38  }
    39  
    40  // httpDir implements http.File for a directory in a FileSystem.
    41  type httpDir struct {
    42  	fs      vfs.FileSystem
    43  	name    string
    44  	pending []os.FileInfo
    45  }
    46  
    47  func (h *httpDir) Close() error               { return nil }
    48  func (h *httpDir) Stat() (os.FileInfo, error) { return h.fs.Stat(h.name) }
    49  func (h *httpDir) Read([]byte) (int, error) {
    50  	return 0, fmt.Errorf("cannot Read from directory %s", h.name)
    51  }
    52  
    53  func (h *httpDir) Seek(offset int64, whence int) (int64, error) {
    54  	if offset == 0 && whence == 0 {
    55  		h.pending = nil
    56  		return 0, nil
    57  	}
    58  	return 0, fmt.Errorf("unsupported Seek in directory %s", h.name)
    59  }
    60  
    61  func (h *httpDir) Readdir(count int) ([]os.FileInfo, error) {
    62  	if h.pending == nil {
    63  		d, err := h.fs.ReadDir(h.name)
    64  		if err != nil {
    65  			return nil, err
    66  		}
    67  		if d == nil {
    68  			d = []os.FileInfo{} // not nil
    69  		}
    70  		h.pending = d
    71  	}
    72  
    73  	if len(h.pending) == 0 && count > 0 {
    74  		return nil, io.EOF
    75  	}
    76  	if count <= 0 || count > len(h.pending) {
    77  		count = len(h.pending)
    78  	}
    79  	d := h.pending[:count]
    80  	h.pending = h.pending[count:]
    81  	return d, nil
    82  }
    83  
    84  // httpFile implements http.File for a file (not directory) in a FileSystem.
    85  type httpFile struct {
    86  	fs vfs.FileSystem
    87  	vfs.ReadSeekCloser
    88  	name string
    89  }
    90  
    91  func (h *httpFile) Stat() (os.FileInfo, error) { return h.fs.Stat(h.name) }
    92  func (h *httpFile) Readdir(int) ([]os.FileInfo, error) {
    93  	return nil, fmt.Errorf("cannot Readdir from file %s", h.name)
    94  }
    95
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