store_client.cc

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
/* DEBUG: section 90    Storage Manager Client-Side Interface */
 
#include "squid.h"
#include "acl/FilledChecklist.h"
#include "base/AsyncCbdataCalls.h"
#include "base/CodeContext.h"
#include "event.h"
#include "globals.h"
#include "HttpReply.h"
#include "HttpRequest.h"
#include "MemBuf.h"
#include "MemObject.h"
#include "mime_header.h"
#include "SquidConfig.h"
#include "StatCounters.h"
#include "Store.h"
#include "store/SwapMetaIn.h"
#include "store_swapin.h"
#include "StoreClient.h"
#if USE_DELAY_POOLS
#include "DelayPools.h"
#endif
 
/*
 * NOTE: 'Header' refers to the swapfile metadata header.
 *   'OBJHeader' refers to the object header, with canonical
 *   processed object headers (which may derive from FTP/HTTP etc
 *   upstream protocols
 *       'Body' refers to the swapfile body, which is the full
 *        HTTP reply (including HTTP headers and body).
 */
static StoreIOState::STRCB storeClientReadBody;
static StoreIOState::STRCB storeClientReadHeader;
static void storeClientCopy2(StoreEntry * e, store_client * sc);
static bool CheckQuickAbortIsReasonable(StoreEntry * entry);
 
CBDATA_CLASS_INIT(store_client);
 
/* StoreClient */
 
bool
StoreClient::onCollapsingPath() const
{
    if (!Config.onoff.collapsed_forwarding)
        return false;
 
    if (!Config.accessList.collapsedForwardingAccess)
        return true;
 
    ACLFilledChecklist checklist(Config.accessList.collapsedForwardingAccess, nullptr, nullptr);
    fillChecklist(checklist);
    return checklist.fastCheck().allowed();
}
 
bool
StoreClient::startCollapsingOn(const StoreEntry &e, const bool doingRevalidation) const
{
    if (!e.hittingRequiresCollapsing())
        return false; // collapsing is impossible due to the entry state
 
    if (!onCollapsingPath())
        return false; // collapsing is impossible due to Squid configuration
 
    /* collapsing is possible; the caller must collapse */
 
    if (const auto tags = loggingTags()) {
        if (doingRevalidation)
            tags->collapsingHistory.revalidationCollapses++;
        else
            tags->collapsingHistory.otherCollapses++;
    }
 
    debugs(85, 5, e << " doingRevalidation=" << doingRevalidation);
    return true;
}
 
/* store_client */
 
int
store_client::getType() const
{
    return type;
}
 
#if STORE_CLIENT_LIST_DEBUG
static store_client *
storeClientListSearch(const MemObject * mem, void *data)
{
    dlink_node *node;
    store_client *sc = NULL;
 
    for (node = mem->clients.head; node; node = node->next) {
        sc = node->data;
 
        if (sc->owner == data)
            return sc;
    }
 
    return NULL;
}
 
int
storeClientIsThisAClient(store_client * sc, void *someClient)
{
    return sc->owner == someClient;
}
 
#endif
#include "HttpRequest.h"
 
/* add client with fd to client list */
store_client *
storeClientListAdd(StoreEntry * e, void *data)
{
    MemObject *mem = e->mem_obj;
    store_client *sc;
    assert(mem);
#if STORE_CLIENT_LIST_DEBUG
 
    if (storeClientListSearch(mem, data) != NULL)
        /* XXX die! */
        assert(1 == 0);
#else
    (void)data;
#endif
 
    sc = new store_client (e);
 
    mem->addClient(sc);
 
    return sc;
}
 
void
store_client::callback(const ssize_t outcome)
{
    if (outcome > 0)
        return noteCopiedBytes(outcome);
 
    if (outcome < 0)
        return fail();
 
    noteEof();
}
 
void
store_client::FinishCallback(store_client * const sc)
{
    sc->finishCallback();
}
 
void
store_client::finishCallback()
{
    Assure(_callback.callback_handler);
    Assure(_callback.notifier);
 
    // callers are not ready to handle a content+error combination
    Assure(object_ok || !copiedSize);
 
    StoreIOBuffer result(copiedSize, copyInto.offset, copyInto.data);
    result.flags.error = object_ok ? 0 : 1;
    copiedSize = 0;
 
    cmp_offset = result.offset + result.length;
    STCB *temphandler = _callback.callback_handler;
    void *cbdata = _callback.callback_data;
    _callback = Callback(nullptr, nullptr);
    copyInto.data = nullptr;
 
    if (cbdataReferenceValid(cbdata))
        temphandler(cbdata, result);
 
    cbdataReferenceDone(cbdata);
}
 
void
store_client::noteCopiedBytes(const size_t bytesCopied)
{
    debugs(90, 5, bytesCopied);
    Assure(bytesCopied > 0);
    Assure(!copiedSize);
    copiedSize = bytesCopied;
    noteNews();
}
 
void
store_client::noteEof()
{
    debugs(90, 5, copiedSize);
    Assure(!copiedSize);
    noteNews();
}
 
store_client::store_client(StoreEntry *e) :
    cmp_offset(0),
#if STORE_CLIENT_LIST_DEBUG
    owner(cbdataReference(data)),
#endif
    entry(e),
    type(e->storeClientType()),
    object_ok(true),
    copiedSize(0)
{
    Assure(entry);
    entry->lock("store_client");
 
    flags.disk_io_pending = false;
    flags.store_copying = false;
    ++ entry->refcount;
 
    if (getType() == STORE_DISK_CLIENT) {
        /* assert we'll be able to get the data we want */
        /* maybe we should open swapin_sio here */
        assert(entry->hasDisk() && !entry->swapoutFailed());
    }
}
 
store_client::~store_client()
{
    assert(entry);
    entry->unlock("store_client");
}
 
/* copy bytes requested by the client */
void
storeClientCopy(store_client * sc,
                StoreEntry * e,
                StoreIOBuffer copyInto,
                STCB * callback,
                void *data)
{
    assert (sc != nullptr);
    sc->copy(e, copyInto,callback,data);
}
 
void
store_client::copy(StoreEntry * anEntry,
                   StoreIOBuffer copyRequest,
                   STCB * callback_fn,
                   void *data)
{
    assert (anEntry == entry);
    assert (callback_fn);
    assert (data);
    assert(!EBIT_TEST(entry->flags, ENTRY_ABORTED));
    debugs(90, 3, "store_client::copy: " << entry->getMD5Text() << ", from " <<
           copyRequest.offset << ", for length " <<
           (int) copyRequest.length << ", cb " << callback_fn << ", cbdata " <<
           data);
 
#if STORE_CLIENT_LIST_DEBUG
 
    assert(this == storeClientListSearch(entry->mem_obj, data));
#endif
 
    assert(!_callback.pending());
#if ONLYCONTIGUOUSREQUESTS
 
    assert(cmp_offset == copyRequest.offset);
#endif
    /* range requests will skip into the body */
    cmp_offset = copyRequest.offset;
    _callback = Callback (callback_fn, cbdataReference(data));
    copyInto.data = copyRequest.data;
    copyInto.length = copyRequest.length;
    copyInto.offset = copyRequest.offset;
 
    static bool copying (false);
    assert (!copying);
    copying = true;
    /* we might be blocking comm reads due to readahead limits
     * now we have a new offset, trigger those reads...
     */
    entry->mem_obj->kickReads();
    copying = false;
 
    anEntry->lock("store_client::copy"); // see deletion note below
 
    storeClientCopy2(entry, this);
 
    // Bug 3480: This store_client object may be deleted now if, for example,
    // the client rejects the hit response copied above. Use on-stack pointers!
 
#if USE_ADAPTATION
    anEntry->kickProducer();
#endif
    anEntry->unlock("store_client::copy");
 
    // Add no code here. This object may no longer exist.
}
 
bool
store_client::moreToSend() const
{
    if (entry->store_status == STORE_PENDING)
        return true; // there may be more coming
 
    /* STORE_OK, including aborted entries: no more data is coming */
 
    const int64_t len = entry->objectLen();
 
    // If we do not know the entry length, then we have to open the swap file.
    const bool canSwapIn = entry->hasDisk();
    if (len < 0)
        return canSwapIn;
 
    if (copyInto.offset >= len)
        return false; // sent everything there is
 
    if (canSwapIn)
        return true; // if we lack prefix, we can swap it in
 
    // If we cannot swap in, make sure we have what we want in RAM. Otherwise,
    // scheduleRead calls scheduleDiskRead which asserts without a swap file.
    const MemObject *mem = entry->mem_obj;
    return mem &&
           mem->inmem_lo <= copyInto.offset && copyInto.offset < mem->endOffset();
}
 
static void
storeClientCopy2(StoreEntry * e, store_client * sc)
{
    /* reentrancy not allowed  - note this could lead to
     * dropped notifications about response data availability
     */
 
    if (sc->flags.store_copying) {
        debugs(90, 3, "prevented recursive copying for " << *e);
        return;
    }
 
    debugs(90, 3, "storeClientCopy2: " << e->getMD5Text());
    assert(sc->_callback.pending());
    /*
     * We used to check for ENTRY_ABORTED here.  But there were some
     * problems.  For example, we might have a slow client (or two) and
     * the peer server is reading far ahead and swapping to disk.  Even
     * if the peer aborts, we want to give the client(s)
     * everything we got before the abort condition occurred.
     */
    sc->doCopy(e);
}
 
void
store_client::doCopy(StoreEntry *anEntry)
{
    Assure(_callback.pending());
    Assure(!flags.disk_io_pending);
    Assure(!flags.store_copying);
 
    assert (anEntry == entry);
    flags.store_copying = true;
    MemObject *mem = entry->mem_obj;
 
    debugs(33, 5, "store_client::doCopy: co: " <<
           copyInto.offset << ", hi: " <<
           mem->endOffset());
 
    if (!moreToSend()) {
        /* There is no more to send! */
        debugs(33, 3, "There is no more to send!");
        noteEof();
        flags.store_copying = false;
        return;
    }
 
    /* Check that we actually have data */
    if (anEntry->store_status == STORE_PENDING && copyInto.offset >= mem->endOffset()) {
        debugs(90, 3, "store_client::doCopy: Waiting for more");
        flags.store_copying = false;
        return;
    }
 
    /*
     * Slight weirdness here.  We open a swapin file for any
     * STORE_DISK_CLIENT, even if we can copy the requested chunk
     * from memory in the next block.  We must try to open the
     * swapin file before sending any data to the client side.  If
     * we postpone the open, and then can not open the file later
     * on, the client loses big time.  Its transfer just gets cut
     * off.  Better to open it early (while the client side handler
     * is clientCacheHit) so that we can fall back to a cache miss
     * if needed.
     */
 
    if (STORE_DISK_CLIENT == getType() && swapin_sio == nullptr) {
        if (!startSwapin())
            return; // failure
    }
    scheduleRead();
}
 
bool
store_client::startSwapin()
{
    debugs(90, 3, "store_client::doCopy: Need to open swap in file");
    /* gotta open the swapin file */
 
    if (storeTooManyDiskFilesOpen()) {
        /* yuck -- this causes a TCP_SWAPFAIL_MISS on the client side */
        fail();
        flags.store_copying = false;
        return false;
    } else if (!flags.disk_io_pending) {
        /* Don't set store_io_pending here */
        storeSwapInStart(this);
 
        if (swapin_sio == nullptr) {
            fail();
            flags.store_copying = false;
            return false;
        }
 
        return true;
    } else {
        debugs(90, DBG_IMPORTANT, "WARNING: Averted multiple fd operation (1)");
        flags.store_copying = false;
        return false;
    }
}
 
void
store_client::noteSwapInDone(const bool error)
{
    Assure(_callback.pending());
    if (error)
        fail();
    else
        noteEof();
}
 
void
store_client::scheduleRead()
{
    MemObject *mem = entry->mem_obj;
 
    if (copyInto.offset >= mem->inmem_lo && copyInto.offset < mem->endOffset())
        scheduleMemRead();
    else
        scheduleDiskRead();
}
 
void
store_client::scheduleDiskRead()
{
    /* What the client wants is not in memory. Schedule a disk read */
    if (getType() == STORE_DISK_CLIENT) {
        // we should have called startSwapin() already
        assert(swapin_sio != nullptr);
    } else if (!swapin_sio && !startSwapin()) {
        debugs(90, 3, "bailing after swapin start failure for " << *entry);
        assert(!flags.store_copying);
        return;
    }
 
    assert(!flags.disk_io_pending);
 
    debugs(90, 3, "reading " << *entry << " from disk");
 
    fileRead();
 
    flags.store_copying = false;
}
 
void
store_client::scheduleMemRead()
{
    /* What the client wants is in memory */
    /* Old style */
    debugs(90, 3, "store_client::doCopy: Copying normal from memory");
    const auto sz = entry->mem_obj->data_hdr.copy(copyInto); // may be <= 0 per copy() API
    callback(sz);
    flags.store_copying = false;
}
 
void
store_client::fileRead()
{
    MemObject *mem = entry->mem_obj;
 
    assert(_callback.pending());
    assert(!flags.disk_io_pending);
    flags.disk_io_pending = true;
 
    if (mem->swap_hdr_sz != 0)
        if (entry->swappingOut())
            assert(mem->swapout.sio->offset() > copyInto.offset + (int64_t)mem->swap_hdr_sz);
 
    storeRead(swapin_sio,
              copyInto.data,
              copyInto.length,
              copyInto.offset + mem->swap_hdr_sz,
              mem->swap_hdr_sz == 0 ? storeClientReadHeader
              : storeClientReadBody,
              this);
}
 
void
store_client::readBody(const char *, ssize_t len)
{
    // Don't assert disk_io_pending here.. may be called by read_header
    flags.disk_io_pending = false;
    assert(_callback.pending());
    debugs(90, 3, "storeClientReadBody: len " << len << "");
 
    if (len < 0)
        return fail();
 
    const auto rep = entry->mem_obj ? &entry->mem().baseReply() : nullptr;
    if (copyInto.offset == 0 && len > 0 && rep && rep->sline.status() == Http::scNone) {
        /* Our structure ! */
        if (!entry->mem_obj->adjustableBaseReply().parseCharBuf(copyInto.data, headersEnd(copyInto.data, len))) {
            debugs(90, DBG_CRITICAL, "ERROR: Could not parse headers from on disk object");
        }
    }
 
    if (len > 0 && rep && entry->mem_obj->inmem_lo == 0 && entry->objectLen() <= (int64_t)Config.Store.maxInMemObjSize && Config.onoff.memory_cache_disk) {
        storeGetMemSpace(len);
        // recheck for the above call may purge entry's data from the memory cache
        if (entry->mem_obj->inmem_lo == 0) {
            /* Copy read data back into memory.
             * copyInto.offset includes headers, which is what mem cache needs
             */
            if (copyInto.offset == entry->mem_obj->endOffset()) {
                entry->mem_obj->write(StoreIOBuffer(len, copyInto.offset, copyInto.data));
            }
        }
    }
 
    callback(len);
}
 
void
store_client::fail()
{
    debugs(90, 3, (object_ok ? "once" : "again"));
    if (!object_ok)
        return; // we failed earlier; nothing to do now
 
    object_ok = false;
 
    noteNews();
}
 
void
store_client::noteNews()
{
    /* synchronous open failures callback from the store,
     * before startSwapin detects the failure.
     * TODO: fix this inconsistent behaviour - probably by
     * having storeSwapInStart become a callback functions,
     * not synchronous
     */
 
    if (!_callback.callback_handler) {
        debugs(90, 5, "client lost interest");
        return;
    }
 
    if (_callback.notifier) {
        debugs(90, 5, "earlier news is being delivered by " << _callback.notifier);
        return;
    }
 
    _callback.notifier = asyncCall(90, 4, "store_client::FinishCallback", cbdataDialer(store_client::FinishCallback, this));
    ScheduleCallHere(_callback.notifier);
 
    Assure(!_callback.pending());
}
 
static void
storeClientReadHeader(void *data, const char *buf, ssize_t len, StoreIOState::Pointer)
{
    store_client *sc = (store_client *)data;
    sc->readHeader(buf, len);
}
 
static void
storeClientReadBody(void *data, const char *buf, ssize_t len, StoreIOState::Pointer)
{
    store_client *sc = (store_client *)data;
    sc->readBody(buf, len);
}
 
void
store_client::readHeader(char const *buf, ssize_t len)
{
    MemObject *const mem = entry->mem_obj;
 
    assert(flags.disk_io_pending);
    flags.disk_io_pending = false;
    assert(_callback.pending());
 
    // abort if we fail()'d earlier
    if (!object_ok)
        return;
 
    if (len < 0)
        return fail();
 
    try {
        Store::UnpackHitSwapMeta(buf, len, *entry);
    } catch (...) {
        debugs(90, DBG_IMPORTANT, "ERROR: Failed to unpack Store entry metadata: " << CurrentException);
        fail();
        return;
    }
 
    /*
     * If our last read got some data the client wants, then give
     * it to them, otherwise schedule another read.
     */
    size_t body_sz = len - mem->swap_hdr_sz;
 
    if (copyInto.offset < static_cast<int64_t>(body_sz)) {
        /*
         * we have (part of) what they want
         */
        size_t copy_sz = min(copyInto.length, body_sz);
        debugs(90, 3, "storeClientReadHeader: copying " << copy_sz << " bytes of body");
        memmove(copyInto.data, copyInto.data + mem->swap_hdr_sz, copy_sz);
 
        readBody(copyInto.data, copy_sz);
 
        return;
    }
 
    /*
     * we don't have what the client wants, but at least we now
     * know the swap header size.
     */
    fileRead();
}
 
/*
 * This routine hasn't been optimised to take advantage of the
 * passed sc. Yet.
 */
int
storeUnregister(store_client * sc, StoreEntry * e, void *data)
{
    MemObject *mem = e->mem_obj;
#if STORE_CLIENT_LIST_DEBUG
    assert(sc == storeClientListSearch(e->mem_obj, data));
#else
    (void)data;
#endif
 
    if (mem == nullptr)
        return 0;
 
    debugs(90, 3, "storeUnregister: called for '" << e->getMD5Text() << "'");
 
    if (sc == nullptr) {
        debugs(90, 3, "storeUnregister: No matching client for '" << e->getMD5Text() << "'");
        return 0;
    }
 
    if (mem->clientCount() == 0) {
        debugs(90, 3, "storeUnregister: Consistency failure - store client being unregistered is not in the mem object's list for '" << e->getMD5Text() << "'");
        return 0;
    }
 
    dlinkDelete(&sc->node, &mem->clients);
    -- mem->nclients;
 
    const auto swapoutFinished = e->swappedOut() || e->swapoutFailed();
    if (e->store_status == STORE_OK && !swapoutFinished)
        e->swapOut();
 
    if (sc->swapin_sio != nullptr) {
        storeClose(sc->swapin_sio, StoreIOState::readerDone);
        sc->swapin_sio = nullptr;
        ++statCounter.swap.ins;
    }
 
    if (sc->_callback.callback_handler || sc->_callback.notifier) {
        debugs(90, 3, "forgetting store_client callback for " << *e);
        // Do not notify: Callers want to stop copying and forget about this
        // pending copy request. Some would mishandle a notification from here.
        if (sc->_callback.notifier)
            sc->_callback.notifier->cancel("storeUnregister");
    }
 
#if STORE_CLIENT_LIST_DEBUG
    cbdataReferenceDone(sc->owner);
 
#endif
 
    // We must lock to safely dereference e below, after deleting sc and after
    // calling CheckQuickAbortIsReasonable().
    e->lock("storeUnregister");
 
    // XXX: We might be inside sc store_client method somewhere up the call
    // stack. TODO: Convert store_client to AsyncJob to make destruction async.
    delete sc;
 
    if (CheckQuickAbortIsReasonable(e))
        e->abort();
    else
        mem->kickReads();
 
#if USE_ADAPTATION
    e->kickProducer();
#endif
 
    e->unlock("storeUnregister");
    return 1;
}
 
/* Call handlers waiting for  data to be appended to E. */
void
StoreEntry::invokeHandlers()
{
    if (EBIT_TEST(flags, DELAY_SENDING)) {
        debugs(90, 3, "DELAY_SENDING is on, exiting " << *this);
        return;
    }
    if (EBIT_TEST(flags, ENTRY_FWD_HDR_WAIT)) {
        debugs(90, 3, "ENTRY_FWD_HDR_WAIT is on, exiting " << *this);
        return;
    }
 
    /* Commit what we can to disk, if appropriate */
    swapOut();
    int i = 0;
    store_client *sc;
    dlink_node *nx = nullptr;
    dlink_node *node;
 
    debugs(90, 3, mem_obj->nclients << " clients; " << *this << ' ' << getMD5Text());
    /* walk the entire list looking for valid callbacks */
 
    const auto savedContext = CodeContext::Current();
    for (node = mem_obj->clients.head; node; node = nx) {
        sc = (store_client *)node->data;
        nx = node->next;
        ++i;
 
        if (!sc->_callback.pending())
            continue;
 
        if (sc->flags.disk_io_pending)
            continue;
 
        if (sc->flags.store_copying)
            continue;
 
        // XXX: If invokeHandlers() is (indirectly) called from a store_client
        // method, then the above three conditions may not be sufficient to
        // prevent us from reentering the same store_client object! This
        // probably does not happen in the current code, but no observed
        // invariant prevents this from (accidentally) happening in the future.
 
        // TODO: Convert store_client into AsyncJob; make this call asynchronous
        CodeContext::Reset(sc->_callback.codeContext);
        debugs(90, 3, "checking client #" << i);
        storeClientCopy2(this, sc);
    }
    CodeContext::Reset(savedContext);
}
 
// Does not account for remote readers/clients.
int
storePendingNClients(const StoreEntry * e)
{
    MemObject *mem = e->mem_obj;
    int npend = nullptr == mem ? 0 : mem->nclients;
    debugs(90, 3, "storePendingNClients: returning " << npend);
    return npend;
}
 
/* return true if the request should be aborted */
static bool
CheckQuickAbortIsReasonable(StoreEntry * entry)
{
    assert(entry);
    debugs(90, 3, "entry=" << *entry);
 
    if (storePendingNClients(entry) > 0) {
        debugs(90, 3, "quick-abort? NO storePendingNClients() > 0");
        return false;
    }
 
    if (Store::Root().transientReaders(*entry)) {
        debugs(90, 3, "quick-abort? NO still have one or more transient readers");
        return false;
    }
 
    if (entry->store_status != STORE_PENDING) {
        debugs(90, 3, "quick-abort? NO store_status != STORE_PENDING");
        return false;
    }
 
    if (EBIT_TEST(entry->flags, ENTRY_SPECIAL)) {
        debugs(90, 3, "quick-abort? NO ENTRY_SPECIAL");
        return false;
    }
 
    if (shutting_down) {
        debugs(90, 3, "quick-abort? YES avoid heavy optional work during shutdown");
        return true;
    }
 
    MemObject * const mem = entry->mem_obj;
    assert(mem);
    debugs(90, 3, "mem=" << mem);
 
    if (mem->request && !mem->request->flags.cachable) {
        debugs(90, 3, "quick-abort? YES !mem->request->flags.cachable");
        return true;
    }
 
    if (EBIT_TEST(entry->flags, KEY_PRIVATE)) {
        debugs(90, 3, "quick-abort? YES KEY_PRIVATE");
        return true;
    }
 
    const auto &reply = mem->baseReply();
 
    if (reply.hdr_sz <= 0) {
        // TODO: Check whether this condition works for HTTP/0 responses.
        debugs(90, 3, "quick-abort? YES no object data received yet");
        return true;
    }
 
    if (Config.quickAbort.min < 0) {
        debugs(90, 3, "quick-abort? NO disabled");
        return false;
    }
 
    if (mem->request && mem->request->range && mem->request->getRangeOffsetLimit() < 0) {
        // the admin has configured "range_offset_limit none"
        debugs(90, 3, "quick-abort? NO admin configured range replies to full-download");
        return false;
    }
 
    if (reply.content_length < 0) {
        // XXX: cf.data.pre does not document what should happen in this case
        // We know that quick_abort is enabled, but no limit can be applied.
        debugs(90, 3, "quick-abort? YES unknown content length");
        return true;
    }
    const auto expectlen = reply.hdr_sz + reply.content_length;
 
    int64_t curlen =  mem->endOffset();
 
    if (curlen > expectlen) {
        debugs(90, 3, "quick-abort? YES bad content length (" << curlen << " of " << expectlen << " bytes received)");
        return true;
    }
 
    if ((expectlen - curlen) < (Config.quickAbort.min << 10)) {
        debugs(90, 3, "quick-abort? NO only a little more object left to receive");
        return false;
    }
 
    if ((expectlen - curlen) > (Config.quickAbort.max << 10)) {
        debugs(90, 3, "quick-abort? YES too much left to go");
        return true;
    }
 
    // XXX: This is absurd! TODO: For positives, "a/(b/c) > d" is "a*c > b*d".
    if (expectlen < 100) {
        debugs(90, 3, "quick-abort? NO avoid FPE");
        return false;
    }
 
    if ((curlen / (expectlen / 100)) > (Config.quickAbort.pct)) {
        debugs(90, 3, "quick-abort? NO past point of no return");
        return false;
    }
 
    debugs(90, 3, "quick-abort? YES default");
    return true;
}
 
void
store_client::dumpStats(MemBuf * output, int clientNumber) const
{
    if (_callback.pending())
        return;
 
    output->appendf("\tClient #%d, %p\n", clientNumber, _callback.callback_data);
    output->appendf("\t\tcopy_offset: %" PRId64 "\n", copyInto.offset);
    output->appendf("\t\tcopy_size: %" PRIuSIZE "\n", copyInto.length);
    output->append("\t\tflags:", 8);
 
    if (flags.disk_io_pending)
        output->append(" disk_io_pending", 16);
 
    if (flags.store_copying)
        output->append(" store_copying", 14);
 
    if (_callback.notifier)
        output->append(" notifying", 10);
 
    output->append("\n",1);
}
 
bool
store_client::Callback::pending() const
{
    return callback_handler && !notifier;
}
 
store_client::Callback::Callback(STCB *function, void *data):
    callback_handler(function),
    callback_data(data),
    codeContext(CodeContext::Current())
{
}
 
#if USE_DELAY_POOLS
int
store_client::bytesWanted() const
{
    // TODO: To avoid using stale copyInto, return zero if !_callback.pending()?
    return delayId.bytesWanted(0, copyInto.length);
}
 
void
store_client::setDelayId(DelayId delay_id)
{
    delayId = delay_id;
}
#endif