wcfs: client: Switch to File IO provided by Pygolang

Starting from version 0.1 pygolang provides File out of the box:

nexedi/pygolang@4690460b
https://pypi.org/project/pygolang/#pygolang-change-history

-> Use it and remove our custom File implementation that originally
served as POC for that pygolang functionality.

setup.py

 # Wendelin.core | pythonic package setup
-# Copyright (C) 2014-2021  Nexedi SA and Contributors.
+# Copyright (C) 2014-2022  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -373,7 +373,7 @@ setup(
                    'ZODB >= 4', # for ZBigFile / ZBigArray
                    'zodbtools >= 0.0.0.dev8', # lib.zodb.dbstoropen + ...
 
-                   'pygolang >= 0.0.8', # defer, sync.WaitGroup, pyx/nogil channels ...
+                   'pygolang >= 0.1', # defer, sync.WaitGroup, pyx/nogil channels ...
 
                    'six',       # compat py2/py3
 

wcfs/client/wcfs.cpp

@@ -229,8 +229,6 @@ using std::min;
 using std::max;
 using std::vector;
 
-namespace ioutil = xgolang::io::ioutil;
-
 
 #define TRACE 0
 #if TRACE
@@ -277,7 +275,7 @@ error WCFS::_headWait(zodb::Tid at) {
 
     // XXX dumb implementation, because _headWait should go away.
     while (1) {
-        tie(xatStr, err) = ioutil::ReadFile(wc._path("head/at"));
+        tie(xatStr, err) = os::ReadFile(wc._path("head/at"));
         if (err != nil)
             return E(err);
 
@@ -321,8 +319,8 @@ pair<Conn, error> WCFS::connect(zodb::Tid at) {
     wconn->_at      = at;
     wconn->_wlink   = wlink;
 
-    os::RegisterAfterFork(newref(
-        static_cast<os::_IAfterFork*>( wconn._ptr() )
+    xos::RegisterAfterFork(newref(
+        static_cast<xos::_IAfterFork*>( wconn._ptr() )
     ));
 
     context::Context pinCtx;
@@ -434,8 +432,8 @@ error _Conn::close() {
     if (!errors::Is(err, context::canceled)) // canceled - ok
         reterr1(err);
 
-    os::UnregisterAfterFork(newref(
-        static_cast<os::_IAfterFork*>( &wconn )
+    xos::UnregisterAfterFork(newref(
+        static_cast<xos::_IAfterFork*>( &wconn )
     ));
 
     return E(eret);

wcfs/client/wcfs.h

@@ -118,7 +118,8 @@ struct VMA;
 namespace wcfs {
 
 using namespace golang;
-namespace os        = xgolang::xos;
+namespace os        = golang::os;
+namespace xos       = xgolang::xos;
 namespace mm        = xgolang::xmm;
 namespace xstrconv  = xgolang::xstrconv;
 namespace log       = xgolang::xlog;
@@ -173,7 +174,7 @@ struct WCFS {
 // Conn logically mirrors ZODB.Connection .
 // It is safe to use Conn from multiple threads simultaneously.
 typedef refptr<struct _Conn> Conn;
-struct _Conn : os::_IAfterFork, object {
+struct _Conn : xos::_IAfterFork, object {
     WCFS        *_wc;
     WatchLink   _wlink; // watch/receive pins for mappings created under this conn
 

wcfs/client/wcfs_misc.cpp

@@ -44,92 +44,10 @@ namespace xos {
 
 namespace io = golang::io;
 
-global<error> ErrClosed = errors::New("file already closed");
-
-
 // TODO -> os.PathError + err=syscall.Errno
 static error _pathError(const char *op, const string &path, int syserr);
 static string _sysErrString(int syserr);
 
-int     _File::_sysfd() const { return _fd; }
-string  _File::Name()   const { return _path; }
-
-_File::_File() {}
-_File::~_File() {}
-void _File::decref() {
-    if (__decref())
-        delete this;
-}
-
-
-tuple<File, error> Open(const string &path, int flags, mode_t mode) {
-    int fd = ::open(path.c_str(), flags, mode);
-    if (fd == -1)
-        return make_tuple(nil, _pathError("open", path, errno));
-
-    File f = adoptref(new _File);
-    f->_path = path;
-    f->_fd   = fd;
-    return make_tuple(f, nil);
-}
-
-error _File::Close() {
-    _File& f = *this;
-
-    int err = ::close(f._fd);
-    if (err != 0)
-        return f._errno("close");
-    f._fd = -1;
-    return nil;
-}
-
-tuple<int, error> _File::Read(void *buf, size_t count) {
-    _File& f = *this;
-    int n;
-
-    n = ::read(f._fd, buf, count);
-    if (n == 0)
-        return make_tuple(n, io::EOF_);
-    if (n < 0)
-        return make_tuple(0, f._errno("read"));
-
-    return make_tuple(n, nil);
-}
-
-tuple <int, error> _File::Write(const void *buf, size_t count) {
-    _File& f = *this;
-    int n, wrote=0;
-
-    // NOTE contrary to write(2) we have to write all data as io.Writer requires.
-    while (count != 0) {
-        n = ::write(f._fd, buf, count);
-        if (n < 0)
-            return make_tuple(wrote, f._errno("write"));
-
-        wrote += n;
-        buf    = ((const char *)buf) + n;
-        count -= n;
-    }
-
-    return make_tuple(wrote, nil);
-}
-
-error _File::Stat(struct stat *st) {
-    _File& f = *this;
-
-    int err = fstat(f._fd, st);
-    if (err != 0)
-        return f._errno("stat");
-    return nil;
-}
-
-
-// _errno returns error corresponding to op(file) and errno.
-error _File::_errno(const char *op) {
-    _File& f = *this;
-    return _pathError(op, f._path, errno);
-}
-
 // _pathError returns os.PathError-like for op/path and system error
 // indicated by syserr.
 static error _pathError(const char *op, const string &path, int syserr) {
@@ -207,7 +125,7 @@ namespace xmm {
 // map memory-maps f.fd[offset +size) somewhere into memory.
 // prot  is PROT_* from mmap(2).
 // flags is MAP_*  from mmap(2); MAP_FIXED must not be used.
-tuple<uint8_t*, error> map(int prot, int flags, xos::File f, off_t offset, size_t size) {
+tuple<uint8_t*, error> map(int prot, int flags, os::File f, off_t offset, size_t size) {
     void *addr;
 
     if (flags & MAP_FIXED)
@@ -223,7 +141,7 @@ tuple<uint8_t*, error> map(int prot, int flags, xos::File f, off_t offset, size_
 // map_into memory-maps f.fd[offset +size) into [addr +size).
 // prot  is PROT_* from mmap(2).
 // flags is MAP_*  from mmap(2); MAP_FIXED is added automatically.
-error map_into(void *addr, size_t size, int prot, int flags, xos::File f, off_t offset) {
+error map_into(void *addr, size_t size, int prot, int flags, os::File f, off_t offset) {
     void *addr2;
 
     addr2 = ::mmap(addr, size, prot, MAP_FIXED | flags, f->_sysfd(), offset);
@@ -245,44 +163,6 @@ error unmap(void *addr, size_t size) {
 }   // xmm::
 
 
-// io::ioutil::
-namespace io {
-namespace ioutil {
-
-tuple<string, error> ReadFile(const string& path) {
-    // errctx is ok as returned by all calls.
-    xos::File f;
-    error     err;
-
-    tie(f, err) = xos::Open(path);
-    if (err != nil)
-        return make_tuple("", err);
-
-    string data;
-    vector<char> buf(4096);
-
-    while (1) {
-        int n;
-        tie(n, err) = f->Read(&buf[0], buf.size());
-        data.append(&buf[0], n);
-        if (err != nil) {
-            if (err == golang::io::EOF_)
-                err = nil;
-            break;
-        }
-    }
-
-    error err2 = f->Close();
-    if (err == nil)
-        err = err2;
-    if (err != nil)
-        data = "";
-    return make_tuple(data, err);
-}
-
-}}  // io::ioutil::
-
-
 // xstrconv::   (strconv-like)
 namespace xstrconv {
 

wcfs/client/wcfs_misc.h

@@ -33,6 +33,7 @@
 #include <stdint.h>
 
 #include <golang/libgolang.h>
+#include <golang/os.h>
 using namespace golang;
 
 #include <string>
@@ -51,63 +52,12 @@ using std::tie;
 using std::vector;
 
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-
 // xgolang::
 namespace xgolang {
 
 // xos::
 namespace xos {
 
-extern global<error> ErrClosed;
-
-
-// os::File mimics os.File from Go.
-// its operations return error with full file context.
-typedef refptr<class _File> File;
-class _File : public object {
-    int    _fd;
-    string _path;
-
-    // don't new - create via open
-private:
-    _File();
-    ~_File();
-    friend tuple<File, error> Open(const string &path, int flags, mode_t mode);
-public:
-    void decref();
-
-public:
-    int     _sysfd() const;
-    string  Name()   const;
-    error   Close();
-
-    // read implements io.Reader from Go: it reads into buf up-to count bytes.
-    // XXX buf -> slice<byte> ?
-    tuple<int, error> Read(void *buf, size_t count);
-
-    // write implements io.Writer from Go: it writes all data from buf.
-    //
-    // NOTE write behaves like io.Writer in Go - it tries to write as much
-    // bytes as requested, and if it could write only less - it returns error.
-    // XXX buf -> slice<byte> ?
-    tuple<int, error> Write(const void *buf, size_t count);
-
-    error   Stat(struct stat *st);
-
-private:
-    error _errno(const char *op);
-};
-
-// Open opens file @path.
-tuple<File, error> Open(const string &path, int flags = O_RDONLY,
-        mode_t mode = S_IRUSR | S_IWUSR | S_IXUSR |
-                      S_IRGRP | S_IWGRP | S_IXGRP |
-                      S_IROTH | S_IWOTH | S_IXOTH);
-
-
 // afterfork
 
 // IAfterFork is the interface that objects must implement to be notified after fork.
@@ -130,21 +80,13 @@ void UnregisterAfterFork(IAfterFork obj);
 
 // xmm::
 namespace xmm {
-    tuple<uint8_t*, error> map(int prot, int flags, xos::File f, off_t offset, size_t size);
-    error map_into(void *addr, size_t size, int prot, int flags, xos::File f, off_t offset);
+    tuple<uint8_t*, error> map(int prot, int flags, os::File f, off_t offset, size_t size);
+    error map_into(void *addr, size_t size, int prot, int flags, os::File f, off_t offset);
     error unmap(void *addr, size_t size);
 
 }   // xmm::
 
 
-// io::ioutil::
-namespace io {
-namespace ioutil {
-
-tuple<string, error> ReadFile(const string& path);
-
-}}  // io::ioutil::
-
 // ---- misc ----
 
 

wcfs/client/wcfs_watchlink.cpp

@@ -63,8 +63,8 @@ pair<WatchLink, error> WCFS::_openwatch() {
 
     wlink->rx_eof     = makechan<structZ>();
 
-    os::RegisterAfterFork(newref(
-        static_cast<os::_IAfterFork*>( wlink._ptr() )
+    xos::RegisterAfterFork(newref(
+        static_cast<xos::_IAfterFork*>( wlink._ptr() )
     ));
 
     context::Context serveCtx;
@@ -100,8 +100,8 @@ error _WatchLink::close() {
     if (err == nil)
         err = err3;
 
-    os::UnregisterAfterFork(newref(
-        static_cast<os::_IAfterFork*>( &wlink )
+    xos::UnregisterAfterFork(newref(
+        static_cast<xos::_IAfterFork*>( &wlink )
     ));
 
     return E(err);

wcfs/client/wcfs_watchlink.h

-// Copyright (C) 2018-2021  Nexedi SA and Contributors.
+// Copyright (C) 2018-2022  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -70,7 +70,7 @@ static_assert(sizeof(rxPkt) == 256, "rxPkt miscompiled"); // NOTE 128 is too low
 //
 // It is safe to use WatchLink from multiple threads simultaneously.
 typedef refptr<class _WatchLink> WatchLink;
-class _WatchLink : public os::_IAfterFork, object {
+class _WatchLink : public xos::_IAfterFork, object {
     WCFS            *_wc;
     os::File        _f;      // head/watch file handle
     string          _rxbuf;  // buffer for data already read from _f