File indexing completed on 2024-05-19 05:28:14

 /*
     This file is part of Konsole, an X terminal.
     SPDX-FileCopyrightText: 2000 Stephan Kulow <coolo@kde.org>
 
     Rewritten for QT4 by e_k <e_k at users.sourceforge.net>, Copyright (C)2008
 
     SPDX-License-Identifier: GPL-2.0-or-later
 
     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.
 
 */
 
 #include <QDebug>
 
 // Own
 #include "BlockArray.h"
 
 // System
 #include <cstdio>
 #include <sys/mman.h>
 #include <sys/param.h>
 #include <unistd.h>
 
 using namespace Konsole;
 
 BlockArray::BlockArray()
     : size(0)
     , current(size_t(-1))
     , index(size_t(-1))
     , lastmap(nullptr)
     , lastmap_index(size_t(-1))
     , lastblock(nullptr)
     , ion(-1)
     , length(0)
 {
     // lastmap_index = index = current = size_t(-1);
     if (blocksize == 0) {
         blocksize = ((sizeof(Block) / getpagesize()) + 1) * getpagesize();
     }
 }
 
 BlockArray::~BlockArray()
 {
     setHistorySize(0);
     Q_ASSERT(!lastblock);
 }
 
 size_t BlockArray::append(Block *block)
 {
     if (!size) {
         return size_t(-1);
     }
 
     ++current;
     if (current >= size) {
         current = 0;
     }
 
     int rc;
     rc = lseek(ion, current * blocksize, SEEK_SET);
     if (rc < 0) {
         perror("HistoryBuffer::add.seek");
         setHistorySize(0);
         return size_t(-1);
     }
     rc = write(ion, block, blocksize);
     if (rc < 0) {
         perror("HistoryBuffer::add.write");
         setHistorySize(0);
         return size_t(-1);
     }
 
     length++;
     if (length > size) {
         length = size;
     }
 
     ++index;
 
     delete block;
     return current;
 }
 
 size_t BlockArray::newBlock()
 {
     if (!size) {
         return size_t(-1);
     }
     append(lastblock);
 
     lastblock = new Block();
     return index + 1;
 }
 
 Block *BlockArray::lastBlock() const
 {
     return lastblock;
 }
 
 bool BlockArray::has(size_t i) const
 {
     if (i == index + 1) {
         return true;
     }
 
     if (i > index) {
         return false;
     }
     if (index - i >= length) {
         return false;
     }
     return true;
 }
 
 const Block *BlockArray::at(size_t i)
 {
     if (i == index + 1) {
         return lastblock;
     }
 
     if (i == lastmap_index) {
         return lastmap;
     }
 
     if (i > index) {
         qDebug() << "BlockArray::at() i > index\n";
         return nullptr;
     }
 
     size_t j = i; // (current - (index - i) + (index/size+1)*size) % size ;
 
     Q_ASSERT(j < size);
     unmap();
 
     Block *block = (Block *)mmap(nullptr, blocksize, PROT_READ, MAP_PRIVATE, ion, j * blocksize);
 
     if (block == (Block *)-1) {
         perror("mmap");
         return nullptr;
     }
 
     lastmap = block;
     lastmap_index = i;
 
     return block;
 }
 
 void BlockArray::unmap()
 {
     if (lastmap) {
         int res = munmap((char *)lastmap, blocksize);
         if (res < 0) {
             perror("munmap");
         }
     }
     lastmap = nullptr;
     lastmap_index = size_t(-1);
 }
 
 bool BlockArray::setSize(size_t newsize)
 {
     return setHistorySize(newsize * 1024 / blocksize);
 }
 
 bool BlockArray::setHistorySize(size_t newsize)
 {
     if (size == newsize) {
         return false;
     }
 
     unmap();
 
     if (!newsize) {
         delete lastblock;
         lastblock = nullptr;
         if (ion >= 0) {
             close(ion);
         }
         ion = -1;
         current = size_t(-1);
         return true;
     }
 
     if (!size) {
         FILE *tmp = tmpfile();
         if (!tmp) {
             perror("konsole: cannot open temp file.\n");
         } else {
             ion = dup(fileno(tmp));
             if (ion < 0) {
                 perror("konsole: cannot dup temp file.\n");
                 fclose(tmp);
             }
         }
         if (ion < 0) {
             return false;
         }
 
         Q_ASSERT(!lastblock);
 
         lastblock = new Block();
         size = newsize;
         return false;
     }
 
     if (newsize > size) {
         increaseBuffer();
         size = newsize;
         return false;
     } else {
         decreaseBuffer(newsize);
         ftruncate(ion, length * blocksize);
         size = newsize;
 
         return true;
     }
 }
 
 void BlockArray::moveBlock(FILE *fion, int cursor, int newpos, char *buffer2)
 {
     int res = fseek(fion, cursor * blocksize, SEEK_SET);
     if (res) {
         perror("fseek");
     }
     res = fread(buffer2, blocksize, 1, fion);
     if (res != 1) {
         perror("fread");
     }
 
     res = fseek(fion, newpos * blocksize, SEEK_SET);
     if (res) {
         perror("fseek");
     }
     res = fwrite(buffer2, blocksize, 1, fion);
     if (res != 1) {
         perror("fwrite");
     }
     //    printf("moving block %d to %d\n", cursor, newpos);
 }
 
 void BlockArray::decreaseBuffer(size_t newsize)
 {
     if (index < newsize) { // still fits in whole
         return;
     }
 
     int offset = (current - (newsize - 1) + size) % size;
 
     if (!offset) {
         return;
     }
 
     // The Block constructor could do somthing in future...
     char *buffer1 = new char[blocksize];
 
     FILE *fion = fdopen(dup(ion), "w+b");
     if (!fion) {
         delete[] buffer1;
         perror("fdopen/dup");
         return;
     }
 
     int firstblock;
     if (current <= newsize) {
         firstblock = current + 1;
     } else {
         firstblock = 0;
     }
 
     size_t oldpos;
     for (size_t i = 0, cursor = firstblock; i < newsize; i++) {
         oldpos = (size + cursor + offset) % size;
         moveBlock(fion, oldpos, cursor, buffer1);
         if (oldpos < newsize) {
             cursor = oldpos;
         } else {
             cursor++;
         }
     }
 
     current = newsize - 1;
     length = newsize;
 
     delete[] buffer1;
 
     fclose(fion);
 }
 
 void BlockArray::increaseBuffer()
 {
     if (index < size) { // not even wrapped once
         return;
     }
 
     int offset = (current + size + 1) % size;
     if (!offset) { // no moving needed
         return;
     }
 
     // The Block constructor could do somthing in future...
     char *buffer1 = new char[blocksize];
     char *buffer2 = new char[blocksize];
 
     int runs = 1;
     int bpr = size; // blocks per run
 
     if (size % offset == 0) {
         bpr = size / offset;
         runs = offset;
     }
 
     FILE *fion = fdopen(dup(ion), "w+b");
     if (!fion) {
         perror("fdopen/dup");
         delete[] buffer1;
         delete[] buffer2;
         return;
     }
 
     int res;
     for (int i = 0; i < runs; i++) {
         // free one block in chain
         int firstblock = (offset + i) % size;
         res = fseek(fion, firstblock * blocksize, SEEK_SET);
         if (res) {
             perror("fseek");
         }
         res = fread(buffer1, blocksize, 1, fion);
         if (res != 1) {
             perror("fread");
         }
         int newpos = 0;
         for (int j = 1, cursor = firstblock; j < bpr; j++) {
             cursor = (cursor + offset) % size;
             newpos = (cursor - offset + size) % size;
             moveBlock(fion, cursor, newpos, buffer2);
         }
         res = fseek(fion, i * blocksize, SEEK_SET);
         if (res) {
             perror("fseek");
         }
         res = fwrite(buffer1, blocksize, 1, fion);
         if (res != 1) {
             perror("fwrite");
         }
     }
     current = size - 1;
     length = size;
 
     delete[] buffer1;
     delete[] buffer2;
 
     fclose(fion);
 }