annotate common.cpp @ 395:bc7a821004bb api-inversion

Invert audioDB::status / audiodb_status().

To do that without breaking abstractions, we actually need a new field
in the status structure, storing the size of the data region.
Previously, this was computed in the audioDB::status request from the
database header, but I'm assuming that "user" code doesn't have access
to such internals.  While we're at it, name some intermediate values in
audioDB::status() so that I don't get confused.

Here's the thing, though: we need to make sure that the adb_t * that we
have from audiodb_open() or audiodb_create() is propagated all the way
through into the C++ routines that implement library functions -- in
particular those which actually write to the database; otherwise we
won't have a consistent view in memory of the header on-disk (as the adb
header that will have been written to disk won't be the same as the one
in memory).

We can do that, by altering the "API" audioDB constructors to take the
adb_t * argument, and setting the adb field in the audioDB object that
we've already introduced to that.  But now we need to be careful a
couple of times: if we have one, then audioDB::initTables() mustn't
stomp on it; also, if we're only constructing an audioDB instance to
fulfil an API request, we mustn't audiodb_close() the one we have when
we destroy the audioDB object, because the adb_t * is the one we have
passed in and are going to reuse in later calls to the API.

The good news is that we can be careful in just these ways with minimal
code.  The really good news is that once the inversion is complete, all
of this horribleness will automatically go away (as there will be no
code which constructs audioDB objects to fulfil API functions).  Hooray!
It's almost like it was all planned this way.

#include "audioDB.h"
extern "C" {
#include "audioDB_API.h"
}

#if defined(O2_DEBUG)
void sigterm_action(int signal, siginfo_t *info, void *context) {
  exit(128+signal);
}

void sighup_action(int signal, siginfo_t *info, void *context) {
  // FIXME: reread any configuration files
}
#endif

int acquire_lock(int fd, bool exclusive) {
  struct flock lock;
  int status;
  
  lock.l_type = exclusive ? F_WRLCK : F_RDLCK;
  lock.l_whence = SEEK_SET;
  lock.l_start = 0;
  lock.l_len = 0; /* "the whole file" */

 retry:
  do {
    status = fcntl(fd, F_SETLKW, &lock);
  } while (status != 0 && errno == EINTR);
  
  if (status) {
    if (errno == EAGAIN) {
      sleep(1);
      goto retry;
    } else {
      return status;
    }
  }
  return 0;
}

int divest_lock(int fd) {
  struct flock lock;

  lock.l_type = F_UNLCK;
  lock.l_whence = SEEK_SET;
  lock.l_start = 0;
  lock.l_len = 0;

  return fcntl(fd, F_SETLKW, &lock);
}

void audioDB::get_lock(int fd, bool exclusive) {
  if(acquire_lock(fd, exclusive)) {
    error("fcntl lock error", "", "fcntl");
  }
}

void audioDB::release_lock(int fd) {
  if (divest_lock(fd)) {
    error("fcntl unlock error", "", "fcntl");
  }
}

void audioDB::error(const char* a, const char* b, const char *sysFunc) {
 

    if(isServer) {
        /* FIXME: I think this is leaky -- we never delete err.
           actually deleting it is tricky, though; it gets placed into
           some soap-internal struct with uncertain extent... -- CSR,
           2007-10-01 */
        char *err = new char[256]; /* FIXME: overflows */
        snprintf(err, 255, "%s: %s\n%s", a, b, sysFunc ? strerror(errno) : "");
        /* FIXME: actually we could usefully do with a properly
           structured type, so that we can throw separate faultstring
           and details.  -- CSR, 2007-10-01 */
        throw(err);
    } else if (UseApiError){
        apierrortemp=-1;
        throw(apierrortemp);
    } else {
        std::cerr << a << ": " << b << std::endl;
        if (sysFunc) {
            perror(sysFunc);
        }
        exit(1);
    }

}

void audioDB::initRNG() {
  rng = gsl_rng_alloc(gsl_rng_mt19937);
  if(!rng) {
    error("could not allocate Random Number Generator");
  }
  /* FIXME: maybe we should use a real source of entropy? */
  gsl_rng_set(rng, time(NULL));
}

void audioDB::initDBHeader(const char* dbName) {
  if(!adb) {
    adb = audiodb_open(dbName, forWrite ? O_RDWR : O_RDONLY);
    if(!adb) {
      error("Failed to open database", dbName);
    }
  }
  dbfid = adb->fd;
  dbH = adb->header;

  CHECKED_MMAP(char *, db, 0, getpagesize());

  // Make some handy tables with correct types
  if(forWrite || (dbH->length > 0)) {
    if(forWrite) {
      fileTableLength = dbH->trackTableOffset - dbH->fileTableOffset;
      trackTableLength = dbH->dataOffset - dbH->trackTableOffset;
      dataBufLength = dbH->timesTableOffset - dbH->dataOffset;
      timesTableLength = dbH->powerTableOffset - dbH->timesTableOffset;
      powerTableLength = dbH->l2normTableOffset - dbH->powerTableOffset;
      l2normTableLength = dbH->dbSize - dbH->l2normTableOffset;
    } else {
      fileTableLength = ALIGN_PAGE_UP(dbH->numFiles * O2_FILETABLE_ENTRY_SIZE);
      trackTableLength = ALIGN_PAGE_UP(dbH->numFiles * O2_TRACKTABLE_ENTRY_SIZE);
      if( dbH->flags & O2_FLAG_LARGE_ADB ){
	dataBufLength = ALIGN_PAGE_UP(dbH->numFiles * O2_FILETABLE_ENTRY_SIZE);
	timesTableLength = ALIGN_PAGE_UP(dbH->numFiles * O2_FILETABLE_ENTRY_SIZE);
	powerTableLength = ALIGN_PAGE_UP(dbH->numFiles * O2_FILETABLE_ENTRY_SIZE);
	l2normTableLength = 0;
      }
      else{
	dataBufLength = ALIGN_PAGE_UP(dbH->length);
	timesTableLength = ALIGN_PAGE_UP(2*(dbH->length / dbH->dim));
	powerTableLength = ALIGN_PAGE_UP(dbH->length / dbH->dim);
	l2normTableLength = ALIGN_PAGE_UP(dbH->length / dbH->dim);
      }
    }
    CHECKED_MMAP(char *, fileTable, dbH->fileTableOffset, fileTableLength);
    CHECKED_MMAP(unsigned *, trackTable, dbH->trackTableOffset, trackTableLength);
    /*
     * No more mmap() for dataBuf
     *
     * FIXME: Actually we do do the mmap() in the two cases where it's
     * still "needed": in pointQuery and in l2norm if dbH->length is
     * non-zero.  Removing those cases too (and deleting the dataBuf
     * variable completely) would be cool.  -- CSR, 2007-11-19
     *
     * CHECKED_MMAP(double *, dataBuf, dbH->dataOffset, dataBufLength);
     */
    if( dbH->flags & O2_FLAG_LARGE_ADB ){
      CHECKED_MMAP(char *, featureFileNameTable, dbH->dataOffset, fileTableLength);
      if( dbH->flags & O2_FLAG_TIMES )
	CHECKED_MMAP(char *, timesFileNameTable, dbH->timesTableOffset, fileTableLength);
      if( dbH->flags & O2_FLAG_POWER )
	CHECKED_MMAP(char *, powerFileNameTable, dbH->powerTableOffset, fileTableLength);
    }
    else{
      CHECKED_MMAP(double *, timesTable, dbH->timesTableOffset, timesTableLength);
      CHECKED_MMAP(double *, powerTable, dbH->powerTableOffset, powerTableLength);
      CHECKED_MMAP(double *, l2normTable, dbH->l2normTableOffset, l2normTableLength);
    }
  }

  // build track offset table
  trackOffsetTable = new off_t[dbH->numFiles];
  Uns32T cumTrack=0;
  for(Uns32T k = 0; k < dbH->numFiles; k++){
    trackOffsetTable[k] = cumTrack;
    cumTrack += trackTable[k] * dbH->dim;
  }

  // Assign correct number of point bits per track in LSH indexing / retrieval
  lsh_n_point_bits = dbH->flags >> 28;
  if( !lsh_n_point_bits )
    lsh_n_point_bits = O2_DEFAULT_LSH_N_POINT_BITS;
}

void audioDB::initInputFile (const char *inFile, bool loadData) {
  if (inFile) {
    if ((infid = open(inFile, O_RDONLY)) < 0) {
      error("can't open input file for reading", inFile, "open");
    }

    if (fstat(infid, &statbuf) < 0) {
      error("fstat error finding size of input", inFile, "fstat");
    }

    if(dbH->dim == 0 && dbH->length == 0) { // empty database
      // initialize with input dimensionality
      if(read(infid, &dbH->dim, sizeof(unsigned)) != sizeof(unsigned)) {
        error("short read of input file", inFile);
      }
      if(dbH->dim == 0) {
        error("dimensionality of zero in input file", inFile);
      }
    } else {
      unsigned test;
      if(read(infid, &test, sizeof(unsigned)) != sizeof(unsigned)) {
        error("short read of input file", inFile);
      }
      if(dbH->dim == 0) {
        error("dimensionality of zero in input file", inFile);
      }
      if(dbH->dim != test) {      
	std::cerr << "error: expected dimension: " << dbH->dim << ", got : " << test <<std::endl;
	error("feature dimensions do not match database table dimensions", inFile);
      }
    }
    
    if (loadData && ((indata = (char *) mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, infid, 0)) == (caddr_t) -1)) {
      error("mmap error for input", inFile, "mmap");
    }
  }
}

void audioDB::initTables(const char* dbName, const char* inFile) {
  /* FIXME: initRNG() really logically belongs in the audioDB
     contructor.  However, there are of the order of four constructors
     at the moment, and more to come from API implementation.  Given
     that duplication, I think this is the least worst place to put
     it; the assumption is that nothing which doesn't look at a
     database will need an RNG.  -- CSR, 2008-07-02 */
  initRNG();
  initDBHeader(dbName);
  if(inFile)
    initInputFile(inFile);
}

// If name is relative path, side effect name with prefix/name
// Do not free original pointer
void audioDB::prefix_name(char** const name, const char* prefix){
  // No prefix if prefix is empty
  if(!prefix)
    return;
  // Allocate new memory, keep old memory
  assert(name && *name);
  if (strlen(*name) + strlen(prefix) + 1 > O2_MAXFILESTR)
    error("error: path prefix + filename too long",prefix);
  // Do not prefix absolute path+filename
  if(**name=='/')
    return;
  // OK to prefix relative path+filename
  char* prefixedName = (char*) malloc(O2_MAXFILESTR);
  sprintf(prefixedName, "%s/%s", prefix, *name);
  *name = prefixedName; // side effect new name to old name
}