gold/dirsearch.cc

   1 // dirsearch.cc -- directory searching for gold
   2
   3 // Copyright 2006, 2007 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cerrno>
  26 #include <cstring>
  27 #include <sys/types.h>
  28 #include <dirent.h>
  29
  30 #include "gold-threads.h"
  31 #include "dirsearch.h"
  32
  33 namespace
  34 {
  35
  36 // Read all the files in a directory.
  37
  38 class Dir_cache
  39 {
  40  public:
  41   Dir_cache(const char* dirname)
  42     : dirname_(dirname), files_()
  43   { }
  44
  45   // Read the files in the directory.
  46   void read_files();
  47
  48   // Return whether a file (a base name) is present in the directory.
  49   bool find(const std::string&) const;
  50
  51  private:
  52   // We can not copy this class.
  53   Dir_cache(const Dir_cache&);
  54   Dir_cache& operator=(const Dir_cache&);
  55
  56   const char* dirname_;
  57   Unordered_set<std::string> files_;
  58 };
  59
  60 void
  61 Dir_cache::read_files()
  62 {
  63   DIR* d = opendir(this->dirname_);
  64   if (d == NULL)
  65     {
  66       // We ignore directories which do not exist.
  67       if (errno != ENOENT)
  68         gold::gold_error(_("%s: can not read directory: %s"),
  69                          this->dirname_, strerror(errno));
  70       return;
  71     }
  72
  73   dirent* de;
  74   while ((de = readdir(d)) != NULL)
  75     this->files_.insert(std::string(de->d_name));
  76
  77   if (closedir(d) != 0)
  78     gold::gold_warning("%s: closedir failed: %s", this->dirname_,
  79                        strerror(errno));
  80 }
  81
  82 bool
  83 Dir_cache::find(const std::string& basename) const
  84 {
  85   return this->files_.find(basename) != this->files_.end();
  86 }
  87
  88 // A mapping from directory names to caches.  A lock permits
  89 // concurrent update.  There is no lock for read operations--some
  90 // other mechanism must be used to prevent reads from conflicting with
  91 // writes.
  92
  93 class Dir_caches
  94 {
  95  public:
  96   Dir_caches()
  97     : lock_(), caches_()
  98   { }
  99
 100   ~Dir_caches();
 101
 102   // Add a cache for a directory.
 103   void add(const char*);
 104
 105   // Look up a directory in the cache.  This much be locked against
 106   // calls to Add.
 107   Dir_cache* lookup(const char*) const;
 108
 109  private:
 110   // We can not copy this class.
 111   Dir_caches(const Dir_caches&);
 112   Dir_caches& operator=(const Dir_caches&);
 113
 114   typedef Unordered_map<const char*, Dir_cache*> Cache_hash;
 115
 116   gold::Lock lock_;
 117   Cache_hash caches_;
 118 };
 119
 120 Dir_caches::~Dir_caches()
 121 {
 122   for (Cache_hash::iterator p = this->caches_.begin();
 123        p != this->caches_.end();
 124        ++p)
 125     delete p->second;
 126 }
 127
 128 void
 129 Dir_caches::add(const char* dirname)
 130 {
 131   {
 132     gold::Hold_lock hl(this->lock_);
 133     if (this->lookup(dirname) != NULL)
 134       return;
 135   }
 136
 137   Dir_cache* cache = new Dir_cache(dirname);
 138
 139   cache->read_files();
 140
 141   {
 142     gold::Hold_lock hl(this->lock_);
 143
 144     std::pair<const char*, Dir_cache*> v(dirname, cache);
 145     std::pair<Cache_hash::iterator, bool> p = this->caches_.insert(v);
 146     gold_assert(p.second);
 147   }
 148 }
 149
 150 Dir_cache*
 151 Dir_caches::lookup(const char* dirname) const
 152 {
 153   Cache_hash::const_iterator p = this->caches_.find(dirname);
 154   if (p == this->caches_.end())
 155     return NULL;
 156   return p->second;
 157 }
 158
 159 // The caches.
 160
 161 Dir_caches* caches;
 162
 163 // A Task to read the directory.
 164
 165 class Dir_cache_task : public gold::Task
 166 {
 167  public:
 168   Dir_cache_task(const char* dir, gold::Task_token& token)
 169     : dir_(dir), token_(token)
 170   { }
 171
 172   Is_runnable_type
 173   is_runnable(gold::Workqueue*);
 174
 175   gold::Task_locker*
 176   locks(gold::Workqueue*);
 177
 178   void
 179   run(gold::Workqueue*);
 180
 181   std::string
 182   get_name() const
 183   { return std::string("Dir_cache_task ") + this->dir_; }
 184
 185  private:
 186   const char* dir_;
 187   gold::Task_token& token_;
 188 };
 189
 190 // We can always run the task to read the directory.
 191
 192 gold::Task::Is_runnable_type
 193 Dir_cache_task::is_runnable(gold::Workqueue*)
 194 {
 195   return IS_RUNNABLE;
 196 }
 197
 198 // Return the locks to hold.  We use a blocker lock to prevent file
 199 // lookups from starting until the directory contents have been read.
 200
 201 gold::Task_locker*
 202 Dir_cache_task::locks(gold::Workqueue* workqueue)
 203 {
 204   return new gold::Task_locker_block(this->token_, workqueue);
 205 }
 206
 207 // Run the task--read the directory contents.
 208
 209 void
 210 Dir_cache_task::run(gold::Workqueue*)
 211 {
 212   caches->add(this->dir_);
 213 }
 214
 215 }
 216
 217 namespace gold
 218 {
 219
 220 void
 221 Dirsearch::initialize(Workqueue* workqueue,
 222                       const General_options::Dir_list* directories)
 223 {
 224   gold_assert(caches == NULL);
 225   caches = new Dir_caches;
 226   this->directories_ = directories;
 227   for (General_options::Dir_list::const_iterator p = directories->begin();
 228        p != directories->end();
 229        ++p)
 230     {
 231       this->token_.add_blocker();
 232       workqueue->queue(new Dir_cache_task(p->name().c_str(), this->token_));
 233     }
 234 }
 235
 236 std::string
 237 Dirsearch::find(const std::string& n1, const std::string& n2,
 238                 bool *is_in_sysroot) const
 239 {
 240   gold_assert(!this->token_.is_blocked());
 241
 242   for (General_options::Dir_list::const_iterator p =
 243          this->directories_->begin();
 244        p != this->directories_->end();
 245        ++p)
 246     {
 247       Dir_cache* pdc = caches->lookup(p->name().c_str());
 248       gold_assert(pdc != NULL);
 249       if (pdc->find(n1))
 250         {
 251           *is_in_sysroot = p->is_in_sysroot();
 252           return p->name() + '/' + n1;
 253         }
 254       if (!n2.empty() && pdc->find(n2))
 255         {
 256           *is_in_sysroot = p->is_in_sysroot();
 257           return p->name() + '/' + n2;
 258         }
 259     }
 260
 261   return std::string();
 262 }
 263
 264 } // End namespace gold.