src/Store.h

   1 /*
   2  *
   3  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   4  * ----------------------------------------------------------
   5  *
   6  *  Squid is the result of efforts by numerous individuals from
   7  *  the Internet community; see the CONTRIBUTORS file for full
   8  *  details.   Many organizations have provided support for Squid's
   9  *  development; see the SPONSORS file for full details.  Squid is
  10  *  Copyrighted (C) 2001 by the Regents of the University of
  11  *  California; see the COPYRIGHT file for full details.  Squid
  12  *  incorporates software developed and/or copyrighted by other
  13  *  sources; see the CREDITS file for full details.
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License as published by
  17  *  the Free Software Foundation; either version 2 of the License, or
  18  *  (at your option) any later version.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  GNU General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License
  26  *  along with this program; if not, write to the Free Software
  27  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  28  *
  29  */
  30 #ifndef SQUID_STORE_H
  31 #define SQUID_STORE_H
  32
  33 /**
  34  \defgroup StoreAPI  Store API
  35  \ingroup FileSystems
  36  */
  37
  38 #include "base/RefCount.h"
  39 #include "comm/forward.h"
  40 #include "CommRead.h"
  41 #include "hash.h"
  42 #include "http/forward.h"
  43 #include "http/RequestMethod.h"
  44 #include "HttpReply.h"
  45 #include "MemObject.h"
  46 #include "Range.h"
  47 #include "RemovalPolicy.h"
  48 #include "StoreIOBuffer.h"
  49 #include "StoreStats.h"
  50
  51 #if USE_SQUID_ESI
  52 #include "esi/Element.h"
  53 #endif
  54
  55 #if HAVE_OSTREAM
  56 #include <ostream>
  57 #endif
  58
  59 class AsyncCall;
  60 class HttpRequest;
  61 class Packer;
  62 class RequestFlags;
  63 class StoreClient;
  64 class StoreSearch;
  65 class SwapDir;
  66
  67 extern StoreIoStats store_io_stats;
  68
  69 /// maximum number of entries per cache_dir
  70 enum { SwapFilenMax = 0xFFFFFF }; // keep in sync with StoreEntry::swap_filen
  71
  72 /**
  73  \ingroup StoreAPI
  74  */
  75 class StoreEntry : public hash_link
  76 {
  77
  78 public:
  79     static DeferredRead::DeferrableRead DeferReader;
  80     bool checkDeferRead(int fd) const;
  81
  82     virtual const char *getMD5Text() const;
  83     StoreEntry();
  84     virtual ~StoreEntry();
  85
  86     virtual HttpReply const *getReply() const;
  87     virtual void write (StoreIOBuffer);
  88
  89     /** Check if the Store entry is emtpty
  90      * \retval true   Store contains 0 bytes of data.
  91      * \retval false  Store contains 1 or more bytes of data.
  92      * \retval false  Store contains negative content !!!!!!
  93      */
  94     virtual bool isEmpty() const {
  95         assert (mem_obj);
  96         return mem_obj->endOffset() == 0;
  97     }
  98     virtual bool isAccepting() const;
  99     virtual size_t bytesWanted(Range<size_t> const aRange, bool ignoreDelayPool = false) const;
 100     virtual void complete();
 101     virtual store_client_t storeClientType() const;
 102     virtual char const *getSerialisedMetaData();
 103     void replaceHttpReply(HttpReply *, bool andStartWriting = true);
 104     void startWriting(); ///< pack and write reply headers and, maybe, body
 105     /// whether we may start writing to disk (now or in the future)
 106     virtual bool mayStartSwapOut();
 107     virtual void trimMemory(const bool preserveSwappable);
 108     void abort();
 109     void unlink();
 110     void makePublic();
 111     void makePrivate();
 112     void setPublicKey();
 113     void setPrivateKey();
 114     void expireNow();
 115     void releaseRequest();
 116     void negativeCache();
 117     void cacheNegatively();             /** \todo argh, why both? */
 118     void invokeHandlers();
 119     void purgeMem();
 120     void cacheInMemory(); ///< start or continue storing in memory cache
 121     void swapOut();
 122     /// whether we are in the process of writing this entry to disk
 123     bool swappingOut() const { return swap_status == SWAPOUT_WRITING; }
 124     void swapOutFileClose(int how);
 125     const char *url() const;
 126     int checkCachable();
 127     int checkNegativeHit() const;
 128     int locked() const;
 129     int validToSend() const;
 130     bool memoryCachable() const; ///< may be cached in memory
 131
 132     /// if needed, initialize mem_obj member w/o URI-related information
 133     MemObject *makeMemObject();
 134
 135     /// initialize mem_obj member (if needed) and supply URI-related info
 136     void createMemObject(const char *storeId, const char *logUri, const HttpRequestMethod &aMethod);
 137
 138     void dump(int debug_lvl) const;
 139     void hashDelete();
 140     void hashInsert(const cache_key *);
 141     void registerAbort(STABH * cb, void *);
 142     void reset();
 143     void setMemStatus(mem_status_t);
 144     void timestampsSet();
 145     void unregisterAbort();
 146     void destroyMemObject();
 147     int checkTooSmall();
 148
 149     void delayAwareRead(const Comm::ConnectionPointer &conn, char *buf, int len, AsyncCall::Pointer callback);
 150
 151     void setNoDelay (bool const);
 152     bool modifiedSince(HttpRequest * request) const;
 153     /// has ETag matching at least one of the If-Match etags
 154     bool hasIfMatchEtag(const HttpRequest &request) const;
 155     /// has ETag matching at least one of the If-None-Match etags
 156     bool hasIfNoneMatchEtag(const HttpRequest &request) const;
 157     /// whether this entry has an ETag; if yes, puts ETag value into parameter
 158     bool hasEtag(ETag &etag) const;
 159
 160     /** What store does this entry belong too ? */
 161     virtual RefCount<SwapDir> store() const;
 162
 163     MemObject *mem_obj;
 164     RemovalPolicyNode repl;
 165     /* START OF ON-DISK STORE_META_STD TLV field */
 166     time_t timestamp;
 167     time_t lastref;
 168     time_t expires;
 169     time_t lastmod;
 170     uint64_t swap_file_sz;
 171     uint16_t refcount;
 172     uint16_t flags;
 173     /* END OF ON-DISK STORE_META_STD */
 174
 175     /// unique ID inside a cache_dir for swapped out entries; -1 for others
 176     sfileno swap_filen:25; // keep in sync with SwapFilenMax
 177
 178     sdirno swap_dirn:7;
 179
 180     mem_status_t mem_status:3;
 181
 182     ping_status_t ping_status:3;
 183
 184     store_status_t store_status:3;
 185
 186     swap_status_t swap_status:3;
 187
 188 public:
 189     static size_t inUseCount();
 190     static void getPublicByRequestMethod(StoreClient * aClient, HttpRequest * request, const HttpRequestMethod& method);
 191     static void getPublicByRequest(StoreClient * aClient, HttpRequest * request);
 192     static void getPublic(StoreClient * aClient, const char *uri, const HttpRequestMethod& method);
 193
 194     virtual bool isNull() {
 195         return false;
 196     };
 197
 198     void *operator new(size_t byteCount);
 199     void operator delete(void *address);
 200     void setReleaseFlag();
 201 #if USE_SQUID_ESI
 202
 203     ESIElement::Pointer cachedESITree;
 204 #endif
 205     /** append bytes to the buffer */
 206     virtual void append(char const *, int len);
 207     /** disable sending content to the clients */
 208     virtual void buffer();
 209     /** flush any buffered content */
 210     virtual void flush();
 211     virtual int64_t objectLen() const;
 212     virtual int64_t contentLen() const;
 213
 214     /// claim shared ownership of this entry (for use in a given context)
 215     /// matching lock() and unlock() contexts eases leak triage but is optional
 216     void lock(const char *context);
 217
 218     /// disclaim shared ownership; may remove entry from store and delete it
 219     /// returns remaning lock level (zero for unlocked and possibly gone entry)
 220     int unlock(const char *context);
 221
 222     /// returns a local concurrent use counter, for debugging
 223     int locks() const { return static_cast<int>(lock_count); }
 224
 225     /// update last reference timestamp and related Store metadata
 226     void touch();
 227
 228     virtual void release();
 229
 230 #if USE_ADAPTATION
 231     /// call back producer when more buffer space is available
 232     void deferProducer(const AsyncCall::Pointer &producer);
 233     /// calls back producer registered with deferProducer
 234     void kickProducer();
 235 #endif
 236
 237 private:
 238     static MemAllocator *pool;
 239
 240     unsigned short lock_count;          /* Assume < 65536! */
 241
 242 #if USE_ADAPTATION
 243     /// producer callback registered with deferProducer
 244     AsyncCall::Pointer deferredProducer;
 245 #endif
 246
 247     bool validLength() const;
 248     bool hasOneOfEtags(const String &reqETags, const bool allowWeakMatch) const;
 249 };
 250
 251 std::ostream &operator <<(std::ostream &os, const StoreEntry &e);
 252
 253 /// \ingroup StoreAPI
 254 class NullStoreEntry:public StoreEntry
 255 {
 256
 257 public:
 258     static NullStoreEntry *getInstance();
 259     bool isNull() {
 260         return true;
 261     }
 262
 263     const char *getMD5Text() const;
 264     HttpReply const *getReply() const { return NULL; }
 265     void write (StoreIOBuffer) {}
 266
 267     bool isEmpty () const {return true;}
 268
 269     virtual size_t bytesWanted(Range<size_t> const aRange, bool ignoreDelayPool = false) const { return aRange.end; }
 270
 271     void operator delete(void *address);
 272     void complete() {}
 273
 274 private:
 275     store_client_t storeClientType() const {return STORE_MEM_CLIENT;}
 276
 277     char const *getSerialisedMetaData();
 278     bool mayStartSwapout() {return false;}
 279
 280     void trimMemory(const bool preserveSwappable) {}
 281
 282     static NullStoreEntry _instance;
 283 };
 284
 285 /// \ingroup StoreAPI
 286 typedef void (*STOREGETCLIENT) (StoreEntry *, void *cbdata);
 287
 288 /**
 289  \ingroup StoreAPI
 290  * Abstract base class that will replace the whole store and swapdir interface.
 291  */
 292 class Store : public RefCountable
 293 {
 294
 295 public:
 296     /** The root store */
 297     static Store &Root() {
 298         if (CurrentRoot == NULL)
 299             fatal("No Store Root has been set");
 300         return *CurrentRoot;
 301     }
 302     static void Root(Store *);
 303     static void Root(RefCount<Store>);
 304     static void Stats(StoreEntry * output);
 305     static void Maintain(void *unused);
 306
 307     virtual ~Store() {}
 308
 309     /** Handle pending callbacks - called by the event loop. */
 310     virtual int callback() = 0;
 311
 312     /** create the resources needed for this store to operate */
 313     virtual void create();
 314
 315     /**
 316      * Notify this store that its disk is full.
 317      \todo XXX move into a protected api call between store files and their stores, rather than a top level api call
 318      */
 319     virtual void diskFull();
 320
 321     /** Retrieve a store entry from the store */
 322     virtual StoreEntry * get(const cache_key *) = 0;
 323
 324     /** \todo imeplement the async version */
 325     virtual void get(String const key , STOREGETCLIENT callback, void *cbdata) = 0;
 326
 327     /* prepare the store for use. The store need not be usable immediately,
 328      * it should respond to readable() and writable() with true as soon
 329      * as it can provide those services
 330      */
 331     virtual void init() = 0;
 332
 333     /**
 334      * The maximum size the store will support in normal use. Inaccuracy is permitted,
 335      * but may throw estimates for memory etc out of whack.
 336      */
 337     virtual uint64_t maxSize() const = 0;
 338
 339     /** The minimum size the store will shrink to via normal housekeeping */
 340     virtual uint64_t minSize() const = 0;
 341
 342     /** current store size */
 343     virtual uint64_t currentSize() const = 0;
 344
 345     /** the total number of objects stored */
 346     virtual uint64_t currentCount() const = 0;
 347
 348     /** the maximum object size that can be stored, -1 if unlimited */
 349     virtual int64_t maxObjectSize() const = 0;
 350
 351     /// collect cache storage-related statistics
 352     virtual void getStats(StoreInfoStats &stats) const = 0;
 353
 354     /**
 355      * Output stats to the provided store entry.
 356      \todo make these calls asynchronous
 357      */
 358     virtual void stat(StoreEntry &) const = 0;
 359
 360     /** Sync the store prior to shutdown */
 361     virtual void sync();
 362
 363     /** remove a Store entry from the store */
 364     virtual void unlink (StoreEntry &);
 365
 366     /* search in the store */
 367     virtual StoreSearch *search(String const url, HttpRequest *) = 0;
 368
 369     /* pulled up from SwapDir for migration.... probably do not belong here */
 370     virtual void reference(StoreEntry &) = 0;   /* Reference this object */
 371
 372     /// Undo reference(), returning false iff idle e should be destroyed
 373     virtual bool dereference(StoreEntry &e, bool wantsLocalMemory) = 0;
 374
 375     virtual void maintain() = 0; /* perform regular maintenance should be private and self registered ... */
 376
 377     // XXX: This method belongs to Store::Root/StoreController, but it is here
 378     // to avoid casting Root() to StoreController until Root() API is fixed.
 379     /// informs stores that this entry will be eventually unlinked
 380     virtual void markForUnlink(StoreEntry &e) {}
 381
 382     // XXX: This method belongs to Store::Root/StoreController, but it is here
 383     // because test cases use non-StoreController derivatives as Root
 384     /// called when the entry is no longer needed by any transaction
 385     virtual void handleIdleEntry(StoreEntry &e) {}
 386
 387     // XXX: This method belongs to Store::Root/StoreController, but it is here
 388     // because test cases use non-StoreController derivatives as Root
 389     /// called to get rid of no longer needed entry data in RAM, if any
 390     virtual void memoryOut(StoreEntry &e, const bool preserveSwappable) {}
 391
 392     // XXX: This method belongs to Store::Root/StoreController, but it is here
 393     // to avoid casting Root() to StoreController until Root() API is fixed.
 394     /// makes the entry available for collapsing future requests
 395     virtual void allowCollapsing(StoreEntry *e, const RequestFlags &reqFlags, const HttpRequestMethod &reqMethod) {}
 396
 397     // XXX: This method belongs to Store::Root/StoreController, but it is here
 398     // to avoid casting Root() to StoreController until Root() API is fixed.
 399     /// marks the entry completed for collapsed requests
 400     virtual void transientsCompleteWriting(StoreEntry &e) {}
 401
 402     // XXX: This method belongs to Store::Root/StoreController, but it is here
 403     // to avoid casting Root() to StoreController until Root() API is fixed.
 404     /// Update local intransit entry after changes made by appending worker.
 405     virtual void syncCollapsed(const sfileno xitIndex) {}
 406
 407     // XXX: This method belongs to Store::Root/StoreController, but it is here
 408     // to avoid casting Root() to StoreController until Root() API is fixed.
 409     /// calls Root().transients->abandon() if transients are tracked
 410     virtual void transientsAbandon(StoreEntry &e) {}
 411
 412     // XXX: This method belongs to Store::Root/StoreController, but it is here
 413     // to avoid casting Root() to StoreController until Root() API is fixed.
 414     /// number of the transient entry readers some time ago
 415     virtual int transientReaders(const StoreEntry &e) const { return 0; }
 416
 417     // XXX: This method belongs to Store::Root/StoreController, but it is here
 418     // to avoid casting Root() to StoreController until Root() API is fixed.
 419     /// disassociates the entry from the intransit table
 420     virtual void transientsDisconnect(MemObject &mem_obj) {}
 421
 422     // XXX: This method belongs to Store::Root/StoreController, but it is here
 423     // to avoid casting Root() to StoreController until Root() API is fixed.
 424     /// removes the entry from the memory cache
 425     virtual void memoryUnlink(StoreEntry &e) {}
 426
 427     // XXX: This method belongs to Store::Root/StoreController, but it is here
 428     // to avoid casting Root() to StoreController until Root() API is fixed.
 429     /// disassociates the entry from the memory cache, preserving cached data
 430     virtual void memoryDisconnect(StoreEntry &e) {}
 431
 432     /// If the entry is not found, return false. Otherwise, return true after
 433     /// tying the entry to this cache and setting inSync to updateCollapsed().
 434     virtual bool anchorCollapsed(StoreEntry &collapsed, bool &inSync) { return false; }
 435
 436     /// update a local collapsed entry with fresh info from this cache (if any)
 437     virtual bool updateCollapsed(StoreEntry &collapsed) { return false; }
 438
 439 private:
 440     static RefCount<Store> CurrentRoot;
 441 };
 442
 443 /// \ingroup StoreAPI
 444 typedef RefCount<Store> StorePointer;
 445
 446 /// \ingroup StoreAPI
 447 size_t storeEntryInUse();
 448
 449 /// \ingroup StoreAPI
 450 const char *storeEntryFlags(const StoreEntry *);
 451
 452 /// \ingroup StoreAPI
 453 void storeEntryReplaceObject(StoreEntry *, HttpReply *);
 454
 455 /// \ingroup StoreAPI
 456 StoreEntry *storeGetPublic(const char *uri, const HttpRequestMethod& method);
 457
 458 /// \ingroup StoreAPI
 459 StoreEntry *storeGetPublicByRequest(HttpRequest * request);
 460
 461 /// \ingroup StoreAPI
 462 StoreEntry *storeGetPublicByRequestMethod(HttpRequest * request, const HttpRequestMethod& method);
 463
 464 /// \ingroup StoreAPI
 465 /// Like storeCreatePureEntry(), but also locks the entry and sets entry key.
 466 StoreEntry *storeCreateEntry(const char *, const char *, const RequestFlags &, const HttpRequestMethod&);
 467
 468 /// \ingroup StoreAPI
 469 /// Creates a new StoreEntry with mem_obj and sets initial flags/states.
 470 StoreEntry *storeCreatePureEntry(const char *storeId, const char *logUrl, const RequestFlags &, const HttpRequestMethod&);
 471
 472 /// \ingroup StoreAPI
 473 void storeInit(void);
 474
 475 /// \ingroup StoreAPI
 476 void storeConfigure(void);
 477
 478 /// \ingroup StoreAPI
 479 void storeFreeMemory(void);
 480
 481 /// \ingroup StoreAPI
 482 int expiresMoreThan(time_t, time_t);
 483
 484 /// \ingroup StoreAPI
 485 void storeAppendPrintf(StoreEntry *, const char *,...) PRINTF_FORMAT_ARG2;
 486
 487 /// \ingroup StoreAPI
 488 void storeAppendVPrintf(StoreEntry *, const char *, va_list ap);
 489
 490 /// \ingroup StoreAPI
 491 int storeTooManyDiskFilesOpen(void);
 492
 493 class SwapDir;
 494 /// \ingroup StoreAPI
 495 void storeHeapPositionUpdate(StoreEntry *, SwapDir *);
 496
 497 /// \ingroup StoreAPI
 498 void storeSwapFileNumberSet(StoreEntry * e, sfileno filn);
 499
 500 /// \ingroup StoreAPI
 501 void storeFsInit(void);
 502
 503 /// \ingroup StoreAPI
 504 void storeFsDone(void);
 505
 506 /// \ingroup StoreAPI
 507 void storeReplAdd(const char *, REMOVALPOLICYCREATE *);
 508
 509 /// \ingroup StoreAPI
 510 extern FREE destroyStoreEntry;
 511
 512 /**
 513  \ingroup StoreAPI
 514  \todo should be a subclass of Packer perhaps ?
 515  */
 516 void packerToStoreInit(Packer * p, StoreEntry * e);
 517
 518 /// \ingroup StoreAPI
 519 void storeGetMemSpace(int size);
 520
 521 #endif /* SQUID_STORE_H */