--- /dev/null
+/*
+ * MemBlob.cc (C) 2009 Francesco Chemolli <kinkie@squid-cache.org>
+ *
+ * SQUID Web Proxy Cache http://www.squid-cache.org/
+ * ----------------------------------------------------------
+ *
+ * Squid is the result of efforts by numerous individuals from
+ * the Internet community; see the CONTRIBUTORS file for full
+ * details. Many organizations have provided support for Squid's
+ * development; see the SPONSORS file for full details. Squid is
+ * Copyrighted (C) 2001 by the Regents of the University of
+ * California; see the COPYRIGHT file for full details. Squid
+ * incorporates software developed and/or copyrighted by other
+ * sources; see the CREDITS file for full details.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
+ */
+
+
+#include "config.h"
+#include "base/TextException.h"
+#include "Debug.h"
+#include "MemBlob.h"
+#if HAVE_IOSTREAM
+#include <iostream>
+#endif
+
+#define MEMBLOB_USES_MEM_POOLS 0
+
+#if MEMBLOB_USES_MEM_POOLS
+#include "protos.h"
+#endif
+
+MemBlobStats MemBlob::Stats;
+InstanceIdDefinitions(MemBlob, "blob");
+
+
+/* MemBlobStats */
+
+MemBlobStats::MemBlobStats(): alloc(0), live(0), append(0)
+{}
+
+std::ostream&
+MemBlobStats::dump(std::ostream &os) const
+{
+ os <<
+ "MemBlob created: " << alloc <<
+ "\nMemBlob alive: " << live <<
+ "\nMemBlob append calls: " << append <<
+ "\nMemBlob currently allocated size: " << liveBytes <<
+ "\nlive MemBlob mean current allocation size: " <<
+ (static_cast<double>(liveBytes)/(live?live:1)) << std::endl;
+ return os;
+}
+
+
+/* MemBlob */
+
+MemBlob::MemBlob(const MemBlob::size_type reserveSize) :
+ mem(NULL), capacity(0), size(0) // will be set by memAlloc
+{
+ debugs(MEMBLOB_DEBUGSECTION,9, HERE << "constructed, this="
+ << static_cast<void*>(this) << " id=" << id
+ << " reserveSize=" << reserveSize);
+ memAlloc(reserveSize);
+}
+
+MemBlob::MemBlob(const char *buffer, const MemBlob::size_type bufSize) :
+ mem(NULL), capacity(0), size(0) // will be set by memAlloc
+{
+ debugs(MEMBLOB_DEBUGSECTION,9, HERE << "constructed, this="
+ << static_cast<void*>(this) << " id=" << id
+ << " buffer=" << static_cast<const void*>(buffer)
+ << " bufSize=" << bufSize);
+ memAlloc(bufSize);
+ append(buffer, bufSize);
+}
+
+MemBlob::~MemBlob()
+{
+#if MEMBLOB_USES_MEM_POOLS
+ //no mempools for now
+ // \todo reinstate mempools use
+ memFreeString(capacity,mem);
+#else
+ xfree(mem);
+#endif
+ Stats.liveBytes -= capacity;
+ --Stats.live;
+
+ debugs(MEMBLOB_DEBUGSECTION,9, HERE << "destructed, this="
+ << static_cast<void*>(this) << " id=" << id
+ << " capacity=" << capacity
+ << " size=" << size);
+}
+
+/**
+ * Given the requested minimum size, return a rounded allocation size
+ * for the backing store.
+ * This is a stopgap call, this job is eventually expected to be handled
+ * by MemPools via memAllocString.
+ */
+MemBlob::size_type
+MemBlob::calcAllocSize(const size_type size) const
+{
+ if (size <= 36) return 36;
+ if (size <= 128) return 128;
+ if (size <= 512) return 512;
+ if (size <= 4096) return RoundTo(size, 512);
+ // XXX: recover squidSystemPageSize functionality. It's easy for
+ // the main squid, harder for tests
+#if 0
+ return RoundTo(size, squidSystemPageSize);
+#else
+ return RoundTo(size, 4096);
+#endif
+}
+
+/** Allocate an available space area of at least minSize bytes in size.
+ * Must be called by constructors and only by constructors.
+ */
+void
+MemBlob::memAlloc(const size_type minSize)
+{
+ size_t actualAlloc = calcAllocSize(minSize);
+
+ Must(!mem);
+#if MEMBLOB_USES_MEM_POOLS
+ // XXX: for now, do without mempools. In order to do it, MemPools
+ // need to be singletons so that initialization order can be enforced
+ mem = static_cast<char*>(memAllocString(minSize, &actualAlloc));
+#else
+ // \todo reinstate mempools use
+ mem = static_cast<char*>(xmalloc(actualAlloc));
+#endif
+ Must(mem);
+
+ capacity = actualAlloc;
+ size = 0;
+ debugs(MEMBLOB_DEBUGSECTION, 8,
+ id << " memAlloc: requested=" << minSize <<
+ ", received=" << capacity);
+ ++Stats.live;
+ ++Stats.alloc;
+ Stats.liveBytes += capacity;
+}
+
+void
+MemBlob::append(const char *source, const size_type n)
+{
+ if (n > 0) { // appending zero bytes is allowed but only affects the stats
+ Must(willFit(n));
+ Must(source);
+ /// \note memcpy() is safe because we copy to an unused area
+ memcpy(mem + size, source, n);
+ size += n;
+ }
+ ++Stats.append;
+}
+
+
+const MemBlobStats&
+MemBlob::GetStats()
+{
+ return Stats;
+}
+
+std::ostream&
+MemBlob::dump(std::ostream &os) const
+{
+ os << "id @" << (void *)this
+ << "mem:" << static_cast<void*>(mem)
+ << ",capacity:" << capacity
+ << ",size:" << size
+ << ",refs:" << RefCountCount() << "; ";
+ return os;
+}
--- /dev/null
+/*
+ * MemBlob.h (C) 2009 Francesco Chemolli <kinkie@squid-cache.org>
+ *
+ * SQUID Web Proxy Cache http://www.squid-cache.org/
+ * ----------------------------------------------------------
+ *
+ * Squid is the result of efforts by numerous individuals from
+ * the Internet community; see the CONTRIBUTORS file for full
+ * details. Many organizations have provided support for Squid's
+ * development; see the SPONSORS file for full details. Squid is
+ * Copyrighted (C) 2001 by the Regents of the University of
+ * California; see the COPYRIGHT file for full details. Squid
+ * incorporates software developed and/or copyrighted by other
+ * sources; see the CREDITS file for full details.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
+ */
+
+#ifndef SQUID_MEMBLOB_H_
+#define SQUID_MEMBLOB_H_
+
+#define MEMBLOB_DEBUGSECTION 24
+
+#include "base/InstanceId.h"
+#include "MemPool.h"
+#include "RefCount.h"
+
+/// Various MemBlob class-wide statistics.
+class MemBlobStats
+{
+public:
+ MemBlobStats();
+
+ /// dumps class-wide statistics
+ std::ostream& dump(std::ostream& os) const;
+
+public:
+ u_int64_t alloc; ///< number of MemBlob instances created so far
+ u_int64_t live; ///< number of MemBlob instances currently alive
+ u_int64_t append; ///< number of MemBlob::append() calls
+ u_int64_t liveBytes; ///< the total size of currently allocated storage
+};
+
+
+/** Refcountable, fixed-size, content-agnostic memory buffer.
+ *
+ * Allocated memory block is divided into two sequential areas:
+ * "used memory" and "available space". The used area can be filled during
+ * construction, grows via the append() call, and can be clear()ed.
+ *
+ * MemBlob users can cooperate to safely share the used area. However, MemBlob
+ * provides weak use accounting and no sharing protections besides refcounting.
+ */
+class MemBlob: public RefCountable
+{
+public:
+ typedef RefCount<MemBlob> Pointer;
+ typedef int32_t size_type;
+
+ MEMPROXY_CLASS(MemBlob);
+
+ /// obtain a const view of class-wide statistics
+ static const MemBlobStats& GetStats();
+
+ /// create a new MemBlob with at least reserveSize capacity
+ explicit MemBlob(const size_type reserveSize);
+
+ /// create a MemBlob containing a copy of the buffer of a given size
+ MemBlob(const char *buffer, const size_type bufferSize);
+
+ virtual ~MemBlob();
+
+ /// the number unused bytes at the end of the allocated blob
+ size_type spaceSize() const { return capacity - size; }
+
+ /** check whether the caller can successfully append() n bytes
+ *
+ * \return true the caller may append() n bytes to this blob now
+ * \param off the end of the blob area currently used by the caller
+ * \param n the total number of bytes the caller wants to append
+ */
+ bool canAppend(const size_type off, const size_type n) const
+ {
+ // TODO: ignore offset (and adjust size) when the blob is not shared?
+ return isAppendOffset(off) && willFit(n);
+ }
+
+ /** copies exactly n bytes from the source to the available space area,
+ * enlarging the used area by n bytes
+ *
+ * \throw TextException if there is not enough space in the blob
+ * \param source raw buffer to be copied
+ * \param n the number of bytes to copy from the source buffer
+ */
+ void append(const char *source, const size_type n);
+
+ /// extends the available space to the entire allocated blob
+ void clear() { size = 0; }
+
+ /// dump debugging information
+ std::ostream & dump(std::ostream &os) const;
+
+public:
+ /* MemBlob users should avoid these and must treat them as read-only */
+ char *mem; ///< raw allocated memory block
+ size_type capacity; ///< size of the raw allocated memory block
+ size_type size; ///< maximum allocated memory in use by callers
+ const InstanceId<MemBlob> id; ///< blob identifier
+
+private:
+ static MemBlobStats Stats; ///< class-wide statistics
+
+ void memAlloc(const size_type memSize);
+ size_type calcAllocSize(const size_type minSize) const;
+
+ /// whether the offset points to the end of the used area
+ bool isAppendOffset(const size_type off) const { return off == size; }
+
+ /// whether n more bytes can be appended
+ bool willFit(const size_type n) const { return n <= spaceSize(); }
+
+ /* copying is not implemented */
+ MemBlob(const MemBlob &);
+ MemBlob& operator =(const MemBlob &);
+};
+
+MEMPROXY_CLASS_INLINE(MemBlob);
+
+#endif /* SQUID_MEMBLOB_H_ */
projects / thirdparty / squid.git / commitdiff
