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nostrfs/writeablefile.go

@@ -0,0 +1,88 @@
+package nostrfs
+
+import (
+	"context"
+	"sync"
+	"syscall"
+
+	"github.com/hanwen/go-fuse/v2/fs"
+	"github.com/hanwen/go-fuse/v2/fuse"
+)
+
+type WriteableFile struct {
+	fs.Inode
+	root    *NostrRoot
+	mu      sync.Mutex
+	data    []byte
+	attr    fuse.Attr
+	onWrite func(string)
+}
+
+var (
+	_ = (fs.NodeOpener)((*WriteableFile)(nil))
+	_ = (fs.NodeReader)((*WriteableFile)(nil))
+	_ = (fs.NodeWriter)((*WriteableFile)(nil))
+	_ = (fs.NodeGetattrer)((*WriteableFile)(nil))
+	_ = (fs.NodeSetattrer)((*WriteableFile)(nil))
+	_ = (fs.NodeFlusher)((*WriteableFile)(nil))
+)
+
+func (r *NostrRoot) NewWriteableFile(data string, ctime, mtime uint64, onWrite func(string)) *WriteableFile {
+	return &WriteableFile{
+		root: r,
+		data: []byte(data),
+		attr: fuse.Attr{
+			Mode:  0666,
+			Ctime: ctime,
+			Mtime: mtime,
+			Size:  uint64(len(data)),
+		},
+		onWrite: onWrite,
+	}
+}
+
+func (f *WriteableFile) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+	return nil, fuse.FOPEN_KEEP_CACHE, fs.OK
+}
+
+func (f *WriteableFile) Write(ctx context.Context, fh fs.FileHandle, data []byte, off int64) (uint32, syscall.Errno) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	end := int64(len(data)) + off
+	if int64(len(f.data)) < end {
+		n := make([]byte, end)
+		copy(n, f.data)
+		f.data = n
+	}
+	copy(f.data[off:off+int64(len(data))], data)
+
+	f.onWrite(string(f.data))
+
+	return uint32(len(data)), fs.OK
+}
+
+func (f *WriteableFile) Getattr(ctx context.Context, fh fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	out.Attr = f.attr
+	out.Attr.Size = uint64(len(f.data))
+	return fs.OK
+}
+
+func (f *WriteableFile) Setattr(ctx context.Context, fh fs.FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
+	return fs.OK
+}
+
+func (f *WriteableFile) Flush(ctx context.Context, fh fs.FileHandle) syscall.Errno {
+	return fs.OK
+}
+
+func (f *WriteableFile) Read(ctx context.Context, fh fs.FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	end := int(off) + len(dest)
+	if end > len(f.data) {
+		end = len(f.data)
+	}
+	return fuse.ReadResultData(f.data[off:end]), fs.OK
+}