binutils-gdb/gold/dirsearch.cc
2015-01-02 00:53:45 +10:30

306 lines
7.0 KiB
C++

// dirsearch.cc -- directory searching for gold
// Copyright (C) 2006-2015 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// This program 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 of the License, or
// (at your option) any later version.
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.
#include "gold.h"
#include <cerrno>
#include <cstring>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include "debug.h"
#include "gold-threads.h"
#include "options.h"
#include "workqueue.h"
#include "dirsearch.h"
namespace
{
// Read all the files in a directory.
class Dir_cache
{
public:
Dir_cache(const char* dirname)
: dirname_(dirname), files_()
{ }
// Read the files in the directory.
void read_files();
// Return whether a file (a base name) is present in the directory.
bool find(const std::string&) const;
private:
// We can not copy this class.
Dir_cache(const Dir_cache&);
Dir_cache& operator=(const Dir_cache&);
const char* dirname_;
Unordered_set<std::string> files_;
};
void
Dir_cache::read_files()
{
DIR* d = opendir(this->dirname_);
if (d == NULL)
{
// We ignore directories which do not exist or are actually file
// names.
if (errno != ENOENT && errno != ENOTDIR)
gold::gold_error(_("%s: can not read directory: %s"),
this->dirname_, strerror(errno));
return;
}
dirent* de;
while ((de = readdir(d)) != NULL)
this->files_.insert(std::string(de->d_name));
if (closedir(d) != 0)
gold::gold_warning("%s: closedir failed: %s", this->dirname_,
strerror(errno));
}
bool
Dir_cache::find(const std::string& basename) const
{
return this->files_.find(basename) != this->files_.end();
}
// A mapping from directory names to caches. A lock permits
// concurrent update. There is no lock for read operations--some
// other mechanism must be used to prevent reads from conflicting with
// writes.
class Dir_caches
{
public:
Dir_caches()
: lock_(), caches_()
{ }
~Dir_caches();
// Add a cache for a directory.
void add(const char*);
// Look up a directory in the cache. This much be locked against
// calls to Add.
Dir_cache* lookup(const char*) const;
private:
// We can not copy this class.
Dir_caches(const Dir_caches&);
Dir_caches& operator=(const Dir_caches&);
typedef Unordered_map<const char*, Dir_cache*> Cache_hash;
gold::Lock lock_;
Cache_hash caches_;
};
Dir_caches::~Dir_caches()
{
for (Cache_hash::iterator p = this->caches_.begin();
p != this->caches_.end();
++p)
delete p->second;
}
void
Dir_caches::add(const char* dirname)
{
{
gold::Hold_lock hl(this->lock_);
if (this->lookup(dirname) != NULL)
return;
}
Dir_cache* cache = new Dir_cache(dirname);
cache->read_files();
{
gold::Hold_lock hl(this->lock_);
std::pair<const char*, Dir_cache*> v(dirname, cache);
std::pair<Cache_hash::iterator, bool> p = this->caches_.insert(v);
gold_assert(p.second);
}
}
Dir_cache*
Dir_caches::lookup(const char* dirname) const
{
Cache_hash::const_iterator p = this->caches_.find(dirname);
if (p == this->caches_.end())
return NULL;
return p->second;
}
// The caches.
Dir_caches* caches;
// A Task to read the directory.
class Dir_cache_task : public gold::Task
{
public:
Dir_cache_task(const char* dir, gold::Task_token& token)
: dir_(dir), token_(token)
{ }
gold::Task_token*
is_runnable();
void
locks(gold::Task_locker*);
void
run(gold::Workqueue*);
std::string
get_name() const
{ return std::string("Dir_cache_task ") + this->dir_; }
private:
const char* dir_;
gold::Task_token& token_;
};
// We can always run the task to read the directory.
gold::Task_token*
Dir_cache_task::is_runnable()
{
return NULL;
}
// Return the locks to hold. We use a blocker lock to prevent file
// lookups from starting until the directory contents have been read.
void
Dir_cache_task::locks(gold::Task_locker* tl)
{
tl->add(this, &this->token_);
}
// Run the task--read the directory contents.
void
Dir_cache_task::run(gold::Workqueue*)
{
caches->add(this->dir_);
}
}
namespace gold
{
// Initialize.
void
Dirsearch::initialize(Workqueue* workqueue,
const General_options::Dir_list* directories)
{
gold_assert(caches == NULL);
caches = new Dir_caches;
this->directories_ = directories;
this->token_.add_blockers(directories->size());
for (General_options::Dir_list::const_iterator p = directories->begin();
p != directories->end();
++p)
workqueue->queue(new Dir_cache_task(p->name().c_str(), this->token_));
}
// Search for a file. NOTE: we only log failed file-lookup attempts
// here. Successfully lookups will eventually get logged in
// File_read::open.
std::string
Dirsearch::find(const std::vector<std::string>& names,
bool* is_in_sysroot, int* pindex,
std::string *found_name) const
{
gold_assert(!this->token_.is_blocked());
gold_assert(*pindex >= 0);
for (unsigned int i = static_cast<unsigned int>(*pindex);
i < this->directories_->size();
++i)
{
const Search_directory* p = &this->directories_->at(i);
Dir_cache* pdc = caches->lookup(p->name().c_str());
gold_assert(pdc != NULL);
for (std::vector<std::string>::const_iterator n = names.begin();
n != names.end();
++n)
{
if (pdc->find(*n))
{
*is_in_sysroot = p->is_in_sysroot();
*pindex = i;
*found_name = *n;
return p->name() + '/' + *n;
}
else
gold_debug(DEBUG_FILES, "Attempt to open %s/%s failed",
p->name().c_str(), (*n).c_str());
}
}
*pindex = -2;
return std::string();
}
// Search for a file in a directory list. This is a low-level function and
// therefore can be used before options and parameters are set.
std::string
Dirsearch::find_file_in_dir_list(const std::string& name,
const General_options::Dir_list& directories,
const std::string& extra_search_dir)
{
struct stat buf;
std::string extra_name = extra_search_dir + '/' + name;
if (stat(extra_name.c_str(), &buf) == 0)
return extra_name;
for (General_options::Dir_list::const_iterator dir = directories.begin();
dir != directories.end();
++dir)
{
std::string full_name = dir->name() + '/' + name;
if (stat(full_name.c_str(), &buf) == 0)
return full_name;
}
return name;
}
} // End namespace gold.