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// dirsearch.cc -- directory searching for gold
#include "gold.h"
#include <cerrno>
#include <cassert>
#include <sys/types.h>
#include <dirent.h>
#include "gold-threads.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.
if (errno == ENOENT)
return;
char *s = NULL;
if (asprintf(&s, _("can not read directory %s"), this->dirname_) < 0)
gold::gold_nomem();
gold::gold_fatal(s, true);
}
dirent* de;
while ((de = readdir(d)) != NULL)
this->files_.insert(std::string(de->d_name));
if (closedir(d) != 0)
gold::gold_fatal("closedir failed", true);
}
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);
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)
{ }
Is_runnable_type is_runnable(gold::Workqueue*);
gold::Task_locker* locks(gold::Workqueue*);
void run(gold::Workqueue*);
private:
const char* dir_;
gold::Task_token& token_;
};
// We can always run the task to read the directory.
gold::Task::Is_runnable_type
Dir_cache_task::is_runnable(gold::Workqueue*)
{
return IS_RUNNABLE;
}
// Return the locks to hold. We use a blocker lock to prevent file
// lookups from starting until the directory contents have been read.
gold::Task_locker*
Dir_cache_task::locks(gold::Workqueue* workqueue)
{
return new gold::Task_locker_block(this->token_, workqueue);
}
// Run the task--read the directory contents.
void
Dir_cache_task::run(gold::Workqueue*)
{
caches.add(this->dir_);
}
}
namespace gold
{
Dirsearch::Dirsearch()
: directories_(), token_()
{
}
void
Dirsearch::add(Workqueue* workqueue, const char* d)
{
this->directories_.push_back(d);
this->token_.add_blocker();
workqueue->queue(new Dir_cache_task(d, this->token_));
}
void
Dirsearch::add(Workqueue* workqueue, const General_options::Dir_list& list)
{
for (General_options::Dir_list::const_iterator p = list.begin();
p != list.end();
++p)
this->add(workqueue, *p);
}
std::string
Dirsearch::find(const std::string& n1, const std::string& n2) const
{
assert(!this->token_.is_blocked());
for (std::list<const char*>::const_iterator p = this->directories_.begin();
p != this->directories_.end();
++p)
{
Dir_cache* pdc = caches.lookup(*p);
assert(pdc != NULL);
if (pdc->find(n1))
return std::string(*p) + '/' + n1;
if (!n2.empty() && pdc->find(n2))
return std::string(*p) + '/' + n2;
}
return std::string();
}
} // End namespace gold.
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