Chad has uploaded a new change for review.
https://gerrit.wikimedia.org/r/172312
Change subject: WIP: Split CDB functions off to its own library
......................................................................
WIP: Split CDB functions off to its own library
Change-Id: Idbbfb582510002375f128916840c5f1cb601998f
---
A .gitignore
A composer.json
A src/CdbException.php
A src/CdbFunctions.php
A src/CdbReader.php
A src/CdbReaderDBA.php
A src/CdbReaderPHP.php
A src/CdbWriter.php
A src/CdbWriterDBA.php
A src/CdbWriterPHP.php
10 files changed, 868 insertions(+), 0 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/cdb refs/changes/12/172312/1
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..48b8bf9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+vendor/
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..c6e6b2f
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,22 @@
+{
+ "name": "cdb",
+ "description": "Constant Database (CDB) wrapper library for PHP. Provides
pure-PHP fallback when dba_* functions are absent.",
+ "license": "GPLv2",
+ "authors": [
+ {
+ "name": "Tim Starling",
+ "email": "[email protected]"
+ },
+ {
+ "name": "Chad Horohoe",
+ "email": "[email protected]"
+ }
+ ],
+ "minimum-stability": "dev",
+ "require": {
+ "php": ">=5.3.2"
+ },
+ "autoload": {
+ "classmap": ["src/"]
+ }
+}
diff --git a/src/CdbException.php b/src/CdbException.php
new file mode 100644
index 0000000..6cda529
--- /dev/null
+++ b/src/CdbException.php
@@ -0,0 +1,26 @@
+<?php
+/**
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Exception for Cdb errors.
+ * This explicitly doesn't subclass MWException to encourage reuse.
+ */
+class CdbException extends Exception {
+}
diff --git a/src/CdbFunctions.php b/src/CdbFunctions.php
new file mode 100644
index 0000000..e74924c
--- /dev/null
+++ b/src/CdbFunctions.php
@@ -0,0 +1,97 @@
+<?php
+/**
+ * This is a port of D.J. Bernstein's CDB to PHP. It's based on the copy that
+ * appears in PHP 5.3. Changes are:
+ * * Error returns replaced with exceptions
+ * * Exception thrown if sizes or offsets are between 2GB and 4GB
+ * * Some variables renamed
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Common functions for readers and writers
+ */
+class CdbFunctions {
+ /**
+ * Take a modulo of a signed integer as if it were an unsigned integer.
+ * $b must be less than 0x40000000 and greater than 0
+ *
+ * @param int $a
+ * @param int $b
+ *
+ * @return int
+ */
+ public static function unsignedMod( $a, $b ) {
+ if ( $a & 0x80000000 ) {
+ $m = ( $a & 0x7fffffff ) % $b + 2 * ( 0x40000000 % $b );
+
+ return $m % $b;
+ } else {
+ return $a % $b;
+ }
+ }
+
+ /**
+ * Shift a signed integer right as if it were unsigned
+ * @param int $a
+ * @param int $b
+ * @return int
+ */
+ public static function unsignedShiftRight( $a, $b ) {
+ if ( $b == 0 ) {
+ return $a;
+ }
+ if ( $a & 0x80000000 ) {
+ return ( ( $a & 0x7fffffff ) >> $b ) | ( 0x40000000 >>
( $b - 1 ) );
+ } else {
+ return $a >> $b;
+ }
+ }
+
+ /**
+ * The CDB hash function.
+ *
+ * @param string $s
+ *
+ * @return int
+ */
+ public static function hash( $s ) {
+ $h = 5381;
+ $len = strlen( $s );
+ for ( $i = 0; $i < $len; $i++ ) {
+ $h5 = ( $h << 5 ) & 0xffffffff;
+ // Do a 32-bit sum
+ // Inlined here for speed
+ $sum = ( $h & 0x3fffffff ) + ( $h5 & 0x3fffffff );
+ $h =
+ (
+ ( $sum & 0x40000000 ? 1 : 0 )
+ + ( $h & 0x80000000 ? 2 : 0 )
+ + ( $h & 0x40000000 ? 1 : 0 )
+ + ( $h5 & 0x80000000 ? 2 : 0 )
+ + ( $h5 & 0x40000000 ? 1 : 0 )
+ ) << 30
+ | ( $sum & 0x3fffffff );
+ $h ^= ord( $s[$i] );
+ $h &= 0xffffffff;
+ }
+
+ return $h;
+ }
+}
diff --git a/src/CdbReader.php b/src/CdbReader.php
new file mode 100644
index 0000000..0ca9b9d
--- /dev/null
+++ b/src/CdbReader.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * Native CDB file reader and writer.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Read from a CDB file.
+ * Native and pure PHP implementations are provided.
+ * http://cr.yp.to/cdb.html
+ */
+abstract class CdbReader {
+ /**
+ * The file handle
+ */
+ protected $handle;
+
+ /**
+ * Open a file and return a subclass instance
+ *
+ * @param string $fileName
+ *
+ * @return CdbReader
+ */
+ public static function open( $fileName ) {
+ return self::haveExtension() ?
+ new CdbReaderDBA( $fileName ) :
+ new CdbReaderPHP( $fileName );
+ }
+
+ /**
+ * Returns true if the native extension is available
+ *
+ * @return bool
+ */
+ public static function haveExtension() {
+ if ( !function_exists( 'dba_handlers' ) ) {
+ return false;
+ }
+ $handlers = dba_handlers();
+ if ( !in_array( 'cdb', $handlers ) || !in_array( 'cdb_make',
$handlers ) ) {
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Create the object and open the file
+ *
+ * @param string $fileName
+ */
+ abstract public function __construct( $fileName );
+
+ /**
+ * Close the file. Optional, you can just let the variable go out of
scope.
+ */
+ abstract public function close();
+
+ /**
+ * Get a value with a given key. Only string values are supported.
+ *
+ * @param string $key
+ */
+ abstract public function get( $key );
+}
diff --git a/src/CdbReaderDBA.php b/src/CdbReaderDBA.php
new file mode 100644
index 0000000..e0cab73
--- /dev/null
+++ b/src/CdbReaderDBA.php
@@ -0,0 +1,44 @@
+<?php
+/**
+ * DBA-based CDB reader/writer
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Reader class which uses the DBA extension
+ */
+class CdbReaderDBA extends CdbReader {
+ public function __construct( $fileName ) {
+ $this->handle = dba_open( $fileName, 'r-', 'cdb' );
+ if ( !$this->handle ) {
+ throw new CdbException( 'Unable to open CDB file "' .
$fileName . '"' );
+ }
+ }
+
+ public function close() {
+ if ( isset( $this->handle ) ) {
+ dba_close( $this->handle );
+ }
+ unset( $this->handle );
+ }
+
+ public function get( $key ) {
+ return dba_fetch( $key, $this->handle );
+ }
+}
diff --git a/src/CdbReaderPHP.php b/src/CdbReaderPHP.php
new file mode 100644
index 0000000..e448414
--- /dev/null
+++ b/src/CdbReaderPHP.php
@@ -0,0 +1,214 @@
+<?php
+/**
+ * This is a port of D.J. Bernstein's CDB to PHP. It's based on the copy that
+ * appears in PHP 5.3. Changes are:
+ * * Error returns replaced with exceptions
+ * * Exception thrown if sizes or offsets are between 2GB and 4GB
+ * * Some variables renamed
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * CDB reader class
+ */
+class CdbReaderPHP extends CdbReader {
+ /** The filename */
+ protected $fileName;
+
+ /* number of hash slots searched under this key */
+ protected $loop;
+
+ /* initialized if loop is nonzero */
+ protected $khash;
+
+ /* initialized if loop is nonzero */
+ protected $kpos;
+
+ /* initialized if loop is nonzero */
+ protected $hpos;
+
+ /* initialized if loop is nonzero */
+ protected $hslots;
+
+ /* initialized if findNext() returns true */
+ protected $dpos;
+
+ /* initialized if cdb_findnext() returns 1 */
+ protected $dlen;
+
+ /**
+ * @param string $fileName
+ * @throws CdbException
+ */
+ public function __construct( $fileName ) {
+ $this->fileName = $fileName;
+ $this->handle = fopen( $fileName, 'rb' );
+ if ( !$this->handle ) {
+ throw new CdbException( 'Unable to open CDB file "' .
$this->fileName . '".' );
+ }
+ $this->findStart();
+ }
+
+ public function close() {
+ if ( isset( $this->handle ) ) {
+ fclose( $this->handle );
+ }
+ unset( $this->handle );
+ }
+
+ /**
+ * @param mixed $key
+ * @return bool|string
+ */
+ public function get( $key ) {
+ // strval is required
+ if ( $this->find( strval( $key ) ) ) {
+ return $this->read( $this->dlen, $this->dpos );
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * @param string $key
+ * @param int $pos
+ * @return bool
+ */
+ protected function match( $key, $pos ) {
+ $buf = $this->read( strlen( $key ), $pos );
+
+ return $buf === $key;
+ }
+
+ protected function findStart() {
+ $this->loop = 0;
+ }
+
+ /**
+ * @throws CdbException
+ * @param int $length
+ * @param int $pos
+ * @return string
+ */
+ protected function read( $length, $pos ) {
+ if ( fseek( $this->handle, $pos ) == -1 ) {
+ // This can easily happen if the internal pointers are
incorrect
+ throw new CdbException(
+ 'Seek failed, file "' . $this->fileName . '"
may be corrupted.' );
+ }
+
+ if ( $length == 0 ) {
+ return '';
+ }
+
+ $buf = fread( $this->handle, $length );
+ if ( $buf === false || strlen( $buf ) !== $length ) {
+ throw new CdbException(
+ 'Read from CDB file failed, file "' .
$this->fileName . '" may be corrupted.' );
+ }
+
+ return $buf;
+ }
+
+ /**
+ * Unpack an unsigned integer and throw an exception if it needs more
than 31 bits
+ * @param string $s
+ * @throws CdbException
+ * @return mixed
+ */
+ protected function unpack31( $s ) {
+ $data = unpack( 'V', $s );
+ if ( $data[1] > 0x7fffffff ) {
+ throw new CdbException(
+ 'Error in CDB file "' . $this->fileName . '",
integer too big.' );
+ }
+
+ return $data[1];
+ }
+
+ /**
+ * Unpack a 32-bit signed integer
+ * @param string $s
+ * @return int
+ */
+ protected function unpackSigned( $s ) {
+ $data = unpack( 'va/vb', $s );
+
+ return $data['a'] | ( $data['b'] << 16 );
+ }
+
+ /**
+ * @param string $key
+ * @return bool
+ */
+ protected function findNext( $key ) {
+ if ( !$this->loop ) {
+ $u = CdbFunctions::hash( $key );
+ $buf = $this->read( 8, ( $u << 3 ) & 2047 );
+ $this->hslots = $this->unpack31( substr( $buf, 4 ) );
+ if ( !$this->hslots ) {
+ return false;
+ }
+ $this->hpos = $this->unpack31( substr( $buf, 0, 4 ) );
+ $this->khash = $u;
+ $u = CdbFunctions::unsignedShiftRight( $u, 8 );
+ $u = CdbFunctions::unsignedMod( $u, $this->hslots );
+ $u <<= 3;
+ $this->kpos = $this->hpos + $u;
+ }
+
+ while ( $this->loop < $this->hslots ) {
+ $buf = $this->read( 8, $this->kpos );
+ $pos = $this->unpack31( substr( $buf, 4 ) );
+ if ( !$pos ) {
+ return false;
+ }
+ $this->loop += 1;
+ $this->kpos += 8;
+ if ( $this->kpos == $this->hpos + ( $this->hslots << 3
) ) {
+ $this->kpos = $this->hpos;
+ }
+ $u = $this->unpackSigned( substr( $buf, 0, 4 ) );
+ if ( $u === $this->khash ) {
+ $buf = $this->read( 8, $pos );
+ $keyLen = $this->unpack31( substr( $buf, 0, 4 )
);
+ if ( $keyLen == strlen( $key ) && $this->match(
$key, $pos + 8 ) ) {
+ // Found
+ $this->dlen = $this->unpack31( substr(
$buf, 4 ) );
+ $this->dpos = $pos + 8 + $keyLen;
+
+ return true;
+ }
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * @param mixed $key
+ * @return bool
+ */
+ protected function find( $key ) {
+ $this->findStart();
+
+ return $this->findNext( $key );
+ }
+}
+
diff --git a/src/CdbWriter.php b/src/CdbWriter.php
new file mode 100644
index 0000000..b0a90c3
--- /dev/null
+++ b/src/CdbWriter.php
@@ -0,0 +1,96 @@
+<?php
+/**
+ * Native CDB file reader and writer.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Write to a CDB file.
+ * Native and pure PHP implementations are provided.
+ * http://cr.yp.to/cdb.html
+ */
+abstract class CdbWriter {
+ /**
+ * The file handle
+ */
+ protected $handle;
+
+ /**
+ * File we'll be writing to when we're done
+ * @var string
+ */
+ protected $realFileName;
+
+ /**
+ * File we write to temporarily until we're done
+ * @var string
+ */
+ protected $tmpFileName;
+
+ /**
+ * Open a writer and return a subclass instance.
+ * The user must have write access to the directory, for temporary file
creation.
+ *
+ * @param string $fileName
+ *
+ * @return CdbWriterDBA|CdbWriterPHP
+ */
+ public static function open( $fileName ) {
+ return CdbReader::haveExtension() ?
+ new CdbWriterDBA( $fileName ) :
+ new CdbWriterPHP( $fileName );
+ }
+
+ /**
+ * Create the object and open the file
+ *
+ * @param string $fileName
+ */
+ abstract public function __construct( $fileName );
+
+ /**
+ * Set a key to a given value. The value will be converted to string.
+ * @param string $key
+ * @param string $value
+ */
+ abstract public function set( $key, $value );
+
+ /**
+ * Close the writer object. You should call this function before the
object
+ * goes out of scope, to write out the final hashtables.
+ */
+ abstract public function close();
+
+ /**
+ * If the object goes out of scope, close it for sanity
+ */
+ public function __destruct() {
+ if ( isset( $this->handle ) ) {
+ $this->close();
+ }
+ }
+
+ /**
+ * Are we running on Windows?
+ * @return bool
+ */
+ protected function isWindows() {
+ return substr( php_uname(), 0, 7 ) == 'Windows';
+ }
+}
diff --git a/src/CdbWriterDBA.php b/src/CdbWriterDBA.php
new file mode 100644
index 0000000..1de371d
--- /dev/null
+++ b/src/CdbWriterDBA.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * DBA-based CDB reader/writer
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Writer class which uses the DBA extension
+ */
+class CdbWriterDBA extends CdbWriter {
+ public function __construct( $fileName ) {
+ $this->realFileName = $fileName;
+ $this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0,
0x7fffffff );
+ $this->handle = dba_open( $this->tmpFileName, 'n', 'cdb_make' );
+ if ( !$this->handle ) {
+ throw new CdbException( 'Unable to open CDB file for
write "' . $fileName . '"' );
+ }
+ }
+
+ public function set( $key, $value ) {
+ return dba_insert( $key, $value, $this->handle );
+ }
+
+ public function close() {
+ if ( isset( $this->handle ) ) {
+ dba_close( $this->handle );
+ }
+ if ( $this->isWindows() ) {
+ unlink( $this->realFileName );
+ }
+ if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
+ throw new CdbException( 'Unable to move the new CDB
file into place.' );
+ }
+ unset( $this->handle );
+ }
+}
diff --git a/src/CdbWriterPHP.php b/src/CdbWriterPHP.php
new file mode 100644
index 0000000..bfc0d87
--- /dev/null
+++ b/src/CdbWriterPHP.php
@@ -0,0 +1,234 @@
+<?php
+/**
+ * This is a port of D.J. Bernstein's CDB to PHP. It's based on the copy that
+ * appears in PHP 5.3. Changes are:
+ * * Error returns replaced with exceptions
+ * * Exception thrown if sizes or offsets are between 2GB and 4GB
+ * * Some variables renamed
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * CDB writer class
+ */
+class CdbWriterPHP extends CdbWriter {
+ protected $hplist;
+
+ protected $numentries;
+
+ protected $pos;
+
+ /**
+ * @param string $fileName
+ */
+ public function __construct( $fileName ) {
+ $this->realFileName = $fileName;
+ $this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0,
0x7fffffff );
+ $this->handle = fopen( $this->tmpFileName, 'wb' );
+ if ( !$this->handle ) {
+ $this->throwException(
+ 'Unable to open CDB file "' .
$this->tmpFileName . '" for write.' );
+ }
+ $this->hplist = array();
+ $this->numentries = 0;
+ $this->pos = 2048; // leaving space for the pointer array, 256
* 8
+ if ( fseek( $this->handle, $this->pos ) == -1 ) {
+ $this->throwException( 'fseek failed in file "' .
$this->tmpFileName . '".' );
+ }
+ }
+
+ /**
+ * @param string $key
+ * @param string $value
+ */
+ public function set( $key, $value ) {
+ if ( strval( $key ) === '' ) {
+ // DBA cross-check hack
+ return;
+ }
+ $this->addbegin( strlen( $key ), strlen( $value ) );
+ $this->write( $key );
+ $this->write( $value );
+ $this->addend( strlen( $key ), strlen( $value ),
CdbFunctions::hash( $key ) );
+ }
+
+ /**
+ * @throws CdbException
+ */
+ public function close() {
+ $this->finish();
+ if ( isset( $this->handle ) ) {
+ fclose( $this->handle );
+ }
+ if ( $this->isWindows() && file_exists( $this->realFileName ) )
{
+ unlink( $this->realFileName );
+ }
+ if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
+ $this->throwException( 'Unable to move the new CDB file
into place.' );
+ }
+ unset( $this->handle );
+ }
+
+ /**
+ * @throws CdbException
+ * @param string $buf
+ */
+ protected function write( $buf ) {
+ $len = fwrite( $this->handle, $buf );
+ if ( $len !== strlen( $buf ) ) {
+ $this->throwException( 'Error writing to CDB file "' .
$this->tmpFileName . '".' );
+ }
+ }
+
+ /**
+ * @throws CdbException
+ * @param int $len
+ */
+ protected function posplus( $len ) {
+ $newpos = $this->pos + $len;
+ if ( $newpos > 0x7fffffff ) {
+ $this->throwException(
+ 'A value in the CDB file "' .
$this->tmpFileName . '" is too large.' );
+ }
+ $this->pos = $newpos;
+ }
+
+ /**
+ * @param int $keylen
+ * @param int $datalen
+ * @param int $h
+ */
+ protected function addend( $keylen, $datalen, $h ) {
+ $this->hplist[] = array(
+ 'h' => $h,
+ 'p' => $this->pos
+ );
+
+ $this->numentries++;
+ $this->posplus( 8 );
+ $this->posplus( $keylen );
+ $this->posplus( $datalen );
+ }
+
+ /**
+ * @throws CdbException
+ * @param int $keylen
+ * @param int $datalen
+ */
+ protected function addbegin( $keylen, $datalen ) {
+ if ( $keylen > 0x7fffffff ) {
+ $this->throwException( 'Key length too long in file "'
. $this->tmpFileName . '".' );
+ }
+ if ( $datalen > 0x7fffffff ) {
+ $this->throwException( 'Data length too long in file "'
. $this->tmpFileName . '".' );
+ }
+ $buf = pack( 'VV', $keylen, $datalen );
+ $this->write( $buf );
+ }
+
+ /**
+ * @throws CdbException
+ */
+ protected function finish() {
+ // Hack for DBA cross-check
+ $this->hplist = array_reverse( $this->hplist );
+
+ // Calculate the number of items that will be in each hashtable
+ $counts = array_fill( 0, 256, 0 );
+ foreach ( $this->hplist as $item ) {
+ ++$counts[255 & $item['h']];
+ }
+
+ // Fill in $starts with the *end* indexes
+ $starts = array();
+ $pos = 0;
+ for ( $i = 0; $i < 256; ++$i ) {
+ $pos += $counts[$i];
+ $starts[$i] = $pos;
+ }
+
+ // Excessively clever and indulgent code to simultaneously fill
$packedTables
+ // with the packed hashtables, and adjust the elements of
$starts
+ // to actually point to the starts instead of the ends.
+ $packedTables = array_fill( 0, $this->numentries, false );
+ foreach ( $this->hplist as $item ) {
+ $packedTables[--$starts[255 & $item['h']]] = $item;
+ }
+
+ $final = '';
+ for ( $i = 0; $i < 256; ++$i ) {
+ $count = $counts[$i];
+
+ // The size of the hashtable will be double the item
count.
+ // The rest of the slots will be empty.
+ $len = $count + $count;
+ $final .= pack( 'VV', $this->pos, $len );
+
+ $hashtable = array();
+ for ( $u = 0; $u < $len; ++$u ) {
+ $hashtable[$u] = array( 'h' => 0, 'p' => 0 );
+ }
+
+ // Fill the hashtable, using the next empty slot if the
hashed slot
+ // is taken.
+ for ( $u = 0; $u < $count; ++$u ) {
+ $hp = $packedTables[$starts[$i] + $u];
+ $where = CdbFunctions::unsignedMod(
+ CdbFunctions::unsignedShiftRight(
$hp['h'], 8 ), $len );
+ while ( $hashtable[$where]['p'] ) {
+ if ( ++$where == $len ) {
+ $where = 0;
+ }
+ }
+ $hashtable[$where] = $hp;
+ }
+
+ // Write the hashtable
+ for ( $u = 0; $u < $len; ++$u ) {
+ $buf = pack( 'vvV',
+ $hashtable[$u]['h'] & 0xffff,
+ CdbFunctions::unsignedShiftRight(
$hashtable[$u]['h'], 16 ),
+ $hashtable[$u]['p'] );
+ $this->write( $buf );
+ $this->posplus( 8 );
+ }
+ }
+
+ // Write the pointer array at the start of the file
+ rewind( $this->handle );
+ if ( ftell( $this->handle ) != 0 ) {
+ $this->throwException( 'Error rewinding to start of
file "' . $this->tmpFileName . '".' );
+ }
+ $this->write( $final );
+ }
+
+ /**
+ * Clean up the temp file and throw an exception
+ *
+ * @param string $msg
+ * @throws CdbException
+ */
+ protected function throwException( $msg ) {
+ if ( $this->handle ) {
+ fclose( $this->handle );
+ unlink( $this->tmpFileName );
+ }
+ throw new CdbException( $msg );
+ }
+}
--
To view, visit https://gerrit.wikimedia.org/r/172312
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: Idbbfb582510002375f128916840c5f1cb601998f
Gerrit-PatchSet: 1
Gerrit-Project: cdb
Gerrit-Branch: master
Gerrit-Owner: Chad <[email protected]>
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