gcc/c++tools/resolver.cc

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/* C++ modules. Experimental! -*- c++ -*-
2022-01-03 10:42:10 +01:00
Copyright (C) 2017-2022 Free Software Foundation, Inc.
Written by Nathan Sidwell <nathan@acm.org> while at FaceBook
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "resolver.h"
// C++
#include <algorithm>
#include <memory>
// C
#include <cstring>
// OS
#include <fcntl.h>
#include <unistd.h>
#if 0 // 1 for testing no mmap
#define MAPPED_READING 0
#else
#ifdef IN_GCC
#if HAVE_MMAP_FILE && _POSIX_MAPPED_FILES > 0
#define MAPPED_READING 1
#else
#define MAPPED_READING 0
#endif
#else
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#define MAPPED_READING 1
#else
#define MAPPED_READING 0
#endif
#endif
#endif
#include <sys/types.h>
#include <sys/stat.h>
#if !defined (IN_GCC) && !MAPPED_READING
#define xmalloc(X) malloc(X)
#endif
#if !HOST_HAS_O_CLOEXEC
#define O_CLOEXEC 0
#endif
#ifndef DIR_SEPARATOR
#define DIR_SEPARATOR '/'
#endif
module_resolver::module_resolver (bool map, bool xlate)
: default_map (map), default_translate (xlate)
{
}
module_resolver::~module_resolver ()
{
if (fd_repo >= 0)
close (fd_repo);
}
bool
module_resolver::set_repo (std::string &&r, bool force)
{
if (force || repo.empty ())
{
repo = std::move (r);
force = true;
}
return force;
}
bool
module_resolver::add_mapping (std::string &&module, std::string &&file,
bool force)
{
auto res = map.emplace (std::move (module), std::move (file));
if (res.second)
force = true;
else if (force)
res.first->second = std::move (file);
return force;
}
int
module_resolver::read_tuple_file (int fd, char const *prefix, bool force)
{
struct stat stat;
if (fstat (fd, &stat) < 0)
return -errno;
if (!stat.st_size)
return 0;
void *buffer = nullptr;
#if MAPPED_READING
// Just map the file, we're gonna read all of it, so no need for
// line buffering
buffer = mmap (nullptr, stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (buffer == MAP_FAILED)
return -errno;
struct Deleter {
void operator()(void* p) const { munmap(p, size); }
size_t size;
};
std::unique_ptr<void, Deleter> guard(buffer, Deleter{(size_t)stat.st_size});
#else
buffer = xmalloc (stat.st_size);
if (!buffer)
return -errno;
struct Deleter { void operator()(void* p) const { free(p); } };
std::unique_ptr<void, Deleter> guard(buffer);
if (read (fd, buffer, stat.st_size) != stat.st_size)
return -errno;
#endif
size_t prefix_len = prefix ? strlen (prefix) : 0;
unsigned lineno = 0;
for (char const *begin = reinterpret_cast <char const *> (buffer),
*end = begin + stat.st_size, *eol;
begin != end; begin = eol + 1)
{
lineno++;
eol = std::find (begin, end, '\n');
if (eol == end)
// last line has no \n, ignore the line, you lose
break;
auto *pos = begin;
bool pfx_search = prefix_len != 0;
pfx_search:
while (*pos == ' ' || *pos == '\t')
pos++;
auto *space = pos;
while (*space != '\n' && *space != ' ' && *space != '\t')
space++;
if (pos == space)
// at end of line, nothing here
continue;
if (pfx_search)
{
if (size_t (space - pos) == prefix_len
&& std::equal (pos, space, prefix))
pfx_search = false;
pos = space;
goto pfx_search;
}
std::string module (pos, space);
while (*space == ' ' || *space == '\t')
space++;
std::string file (space, eol);
if (module[0] == '$')
{
if (module == "$root")
set_repo (std::move (file));
else
return lineno;
}
else
{
if (file.empty ())
file = GetCMIName (module);
add_mapping (std::move (module), std::move (file), force);
}
}
return 0;
}
char const *
module_resolver::GetCMISuffix ()
{
return "gcm";
}
module_resolver *
module_resolver::ConnectRequest (Cody::Server *s, unsigned version,
std::string &a, std::string &i)
{
if (!version || version > Cody::Version)
s->ErrorResponse ("version mismatch");
else if (a != "GCC")
// Refuse anything but GCC
ErrorResponse (s, std::string ("only GCC supported"));
else if (!ident.empty () && ident != i)
// Failed ident check
ErrorResponse (s, std::string ("bad ident"));
else
// Success!
s->ConnectResponse ("gcc");
return this;
}
int
module_resolver::ModuleRepoRequest (Cody::Server *s)
{
s->PathnameResponse (repo);
return 0;
}
int
module_resolver::cmi_response (Cody::Server *s, std::string &module)
{
auto iter = map.find (module);
if (iter == map.end ())
{
std::string file = default_map ? GetCMIName (module) : std::string ();
auto res = map.emplace (module, file);
iter = res.first;
}
if (iter->second.empty ())
s->ErrorResponse ("no such module");
else
s->PathnameResponse (iter->second);
return 0;
}
int
module_resolver::ModuleExportRequest (Cody::Server *s, Cody::Flags,
std::string &module)
{
return cmi_response (s, module);
}
int
module_resolver::ModuleImportRequest (Cody::Server *s, Cody::Flags,
std::string &module)
{
return cmi_response (s, module);
}
int
module_resolver::IncludeTranslateRequest (Cody::Server *s, Cody::Flags,
std::string &include)
{
auto iter = map.find (include);
if (iter == map.end () && default_translate)
{
// Not found, look for it
auto file = GetCMIName (include);
struct stat statbuf;
bool ok = true;
#if HAVE_FSTATAT
int fd_dir = AT_FDCWD;
if (!repo.empty ())
{
if (fd_repo == -1)
{
fd_repo = open (repo.c_str (),
O_RDONLY | O_CLOEXEC | O_DIRECTORY);
if (fd_repo < 0)
fd_repo = -2;
}
fd_dir = fd_repo;
}
if (!repo.empty () && fd_repo < 0)
ok = false;
else if (fstatat (fd_dir, file.c_str (), &statbuf, 0) < 0
|| !S_ISREG (statbuf.st_mode))
ok = false;
#else
auto append = repo;
append.push_back (DIR_SEPARATOR);
append.append (file);
if (stat (append.c_str (), &statbuf) < 0
|| !S_ISREG (statbuf.st_mode))
ok = false;
#endif
if (!ok)
// Mark as not present
file.clear ();
auto res = map.emplace (include, file);
iter = res.first;
}
if (iter == map.end () || iter->second.empty ())
s->BoolResponse (false);
else
s->PathnameResponse (iter->second);
return 0;
}
/* This handles a client notification to the server that a CMI has been
produced for a module. For this simplified server, we just accept
the transaction and respond with "OK". */
int
module_resolver::ModuleCompiledRequest (Cody::Server *s, Cody::Flags,
std::string &)
{
s->OKResponse();
return 0;
}