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