Move disk image reading to be behind an ImgFile class

Allows different implementations for different platforms (the JS
build relies on browser APIs to stream disk images over the network).

Setting aside the JS build, this also reduces some code duplication.

Author: mihaip

devices/common/ata/atahd.cpp

@@ -24,7 +24,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <devices/common/ata/atahd.h>
 
 #include <cstring>
-#include <sys/stat.h>
 #include <fstream>
 #include <string>
 #include <loguru.hpp>
@@ -35,16 +34,11 @@ AtaHardDisk::AtaHardDisk() : AtaBaseDevice("ATA-HD", DEVICE_TYPE_ATA) {
 }
 
 void AtaHardDisk::insert_image(std::string filename) {
-    this->hdd_img.open(filename, std::fstream::out | std::fstream::in | std::fstream::binary);
-
-    struct stat stat_buf;
-    int rc = stat(filename.c_str(), &stat_buf);
-    if (!rc) {
-        this->img_size = stat_buf.st_size;
-    } else {
-        ABORT_F("AtaHardDisk: could not determine file size using stat()");
+    if (!this->hdd_img.open(filename)) {
+        ABORT_F("AtaHardDisk: could not open image file");
     }
-    this->hdd_img.seekg(0, std::ios_base::beg);
+
+    this->img_size = this->hdd_img.size();
 }
 
 int AtaHardDisk::perform_command()
@@ -56,7 +50,6 @@ int AtaHardDisk::perform_command()
     case NOP:
         break;
     case RECALIBRATE:
-        hdd_img.seekg(0, std::ios::beg);
         this->r_error       = 0;
         this->r_cylinder_lo = 0;
         this->r_cylinder_hi = 0;
@@ -68,8 +61,7 @@ int AtaHardDisk::perform_command()
         uint32_t sector = (r_sect_num << 16);
         sector |= ((this->r_cylinder_lo) << 8) + (this->r_cylinder_hi);
         uint64_t offset = sector * ATA_HD_SEC_SIZE;
-        hdd_img.seekg(offset, std::ios::beg);
-        hdd_img.read(buffer, sec_count * ATA_HD_SEC_SIZE);
+        hdd_img.read(buffer, offset, sec_count * ATA_HD_SEC_SIZE);
         this->r_status &= ~DRQ;
     }
     break;
@@ -80,8 +72,7 @@ int AtaHardDisk::perform_command()
         uint32_t sector    = (r_sect_num << 16);
         sector |= ((this->r_cylinder_lo) << 8) + (this->r_cylinder_hi);
         uint64_t offset = sector * ATA_HD_SEC_SIZE;
-        hdd_img.seekg(offset, std::ios::beg);
-        hdd_img.write(buffer, sec_count * ATA_HD_SEC_SIZE);
+        hdd_img.write(buffer, offset, sec_count * ATA_HD_SEC_SIZE);
         this->r_status &= ~DRQ;
     }
     break;

devices/common/ata/atahd.h

@@ -25,8 +25,9 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #define ATA_HARD_DISK_H
 
 #include <devices/common/ata/atabasedevice.h>
+#include <utils/imgfile.h>
+
 #include <string>
-#include <fstream>
 
 #define ATA_HD_SEC_SIZE 512
 
@@ -40,7 +41,7 @@ class AtaHardDisk : public AtaBaseDevice
     int perform_command() override;
 
 private:
-    std::fstream hdd_img;
+    ImgFile         hdd_img;
     uint64_t img_size;
     char * buffer = new char[1 <<17];
 

devices/common/scsi/scsicdrom.cpp

@@ -30,7 +30,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <cinttypes>
 #include <cstring>
-#include <sys/stat.h>
 
 using namespace std;
 
@@ -50,25 +49,20 @@ ScsiCdrom::ScsiCdrom(int my_id) : ScsiDevice(my_id)
 
 void ScsiCdrom::insert_image(std::string filename)
 {
-    this->cdr_img.open(filename, ios::out | ios::in | ios::binary);
+    if (!this->cdr_img.open(filename)) {
+        ABORT_F("SCSI-CDROM: could not open image file");
+    }
 
-    struct stat stat_buf;
-    int rc = stat(filename.c_str(), &stat_buf);
-    if (!rc) {
-        this->img_size = stat_buf.st_size;
-        this->total_frames = (this->img_size + this->sector_size - 1) / this->sector_size;
+    this->img_size = this->cdr_img.size();
+    this->total_frames = (this->img_size + this->sector_size - 1) / this->sector_size;
 
-        // create single track descriptor
-        this->tracks[0]  = {.trk_num = 1, .adr_ctrl = 0x14, .start_lba = 0};
-        this->num_tracks = 1;
+    // create single track descriptor
+    this->tracks[0]  = {.trk_num = 1, .adr_ctrl = 0x14, .start_lba = 0};
+    this->num_tracks = 1;
 
-        // create Lead-out descriptor containing all data
-        this->tracks[1] = {.trk_num = LEAD_OUT_TRK_NUM, .adr_ctrl = 0x14,
-            .start_lba = static_cast<uint32_t>(this->total_frames)};
-    } else {
-        ABORT_F("SCSI-CDROM: could not determine file size using stat()");
-    }
-    this->cdr_img.seekg(0, std::ios_base::beg);
+    // create Lead-out descriptor containing all data
+    this->tracks[1] = {.trk_num = LEAD_OUT_TRK_NUM, .adr_ctrl = 0x14,
+        .start_lba = static_cast<uint32_t>(this->total_frames)};
 }
 
 void ScsiCdrom::process_command()
@@ -155,8 +149,7 @@ void ScsiCdrom::read(const uint32_t lba, const uint16_t transfer_len, const uint
     transfer_size *= this->sector_size;
     uint64_t device_offset = lba * this->sector_size;
 
-    this->cdr_img.seekg(device_offset, this->cdr_img.beg);
-    this->cdr_img.read(this->data_buf, transfer_size);
+    this->cdr_img.read(this->data_buf, device_offset, transfer_size);
 
     this->bytes_out = transfer_size;
     this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;

devices/common/scsi/scsicdrom.h

@@ -25,9 +25,9 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #define SCSI_CDROM_H
 
 #include <devices/common/scsi/scsi.h>
+#include <utils/imgfile.h>
 
 #include <cinttypes>
-#include <fstream>
 #include <memory>
 #include <string>
 
@@ -74,7 +74,7 @@ class ScsiCdrom : public ScsiDevice {
     AddrMsf lba_to_msf(const int lba);
 
 private:
-    std::fstream    cdr_img;
+    ImgFile         cdr_img;
     uint64_t        img_size;
     int             total_frames;
     int             num_tracks;

devices/common/scsi/scsihd.cpp

@@ -30,7 +30,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <fstream>
 #include <cstring>
-#include <sys/stat.h>
 
 #define HDD_SECTOR_SIZE 512
 
@@ -43,17 +42,12 @@ ScsiHardDisk::ScsiHardDisk(int my_id) : ScsiDevice(my_id) {
 void ScsiHardDisk::insert_image(std::string filename) {
     //We don't want to store everything in memory, but
     //we want to keep the hard disk available.
-    this->hdd_img.open(filename, ios::out | ios::in | ios::binary);
-
-    struct stat stat_buf;
-    int rc = stat(filename.c_str(), &stat_buf);
-    if (!rc) {
-        this->img_size = stat_buf.st_size;
-        this->total_blocks = (this->img_size + HDD_SECTOR_SIZE - 1) / HDD_SECTOR_SIZE;
-    } else {
-        ABORT_F("ScsiHardDisk: could not determine file size using stat()");
+    if (!this->hdd_img.open(filename)) {
+        ABORT_F("ScsiHardDisk: could not open image file");
     }
-    this->hdd_img.seekg(0, std::ios_base::beg);
+
+    this->img_size = this->hdd_img.size();
+    this->total_blocks = (this->img_size + HDD_SECTOR_SIZE - 1) / HDD_SECTOR_SIZE;
 }
 
 void ScsiHardDisk::process_command() {
@@ -267,8 +261,7 @@ void ScsiHardDisk::read(uint32_t lba, uint16_t transfer_len, uint8_t cmd_len) {
     transfer_size *= HDD_SECTOR_SIZE;
     uint64_t device_offset = lba * HDD_SECTOR_SIZE;
 
-    this->hdd_img.seekg(device_offset, this->hdd_img.beg);
-    this->hdd_img.read(img_buffer, transfer_size);
+    this->hdd_img.read(img_buffer, device_offset, transfer_size);
 
     this->cur_buf_cnt = transfer_size;
     this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;
@@ -288,20 +281,17 @@ void ScsiHardDisk::write(uint32_t lba, uint16_t transfer_len, uint8_t cmd_len) {
 
     this->incoming_size = transfer_size;
 
-    this->hdd_img.seekg(device_offset, this->hdd_img.beg);
-
-    this->post_xfer_action = [this]() {
-        this->hdd_img.write(this->img_buffer, this->incoming_size);
+    this->post_xfer_action = [this, device_offset]() {
+        this->hdd_img.write(this->img_buffer, device_offset, this->incoming_size);
     };
 }
 
 void ScsiHardDisk::seek(uint32_t lba) {
-    uint64_t device_offset = lba * HDD_SECTOR_SIZE;
-    this->hdd_img.seekg(device_offset, this->hdd_img.beg);
+    // No-op
 }
 
 void ScsiHardDisk::rewind() {
-    this->hdd_img.seekg(0, this->hdd_img.beg);
+    // No-op
 }
 
 static const PropMap SCSI_HD_Properties = {

devices/common/scsi/scsihd.h

@@ -25,9 +25,9 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #define SCSI_HD_H
 
 #include <devices/common/scsi/scsi.h>
+#include <utils/imgfile.h>
 
 #include <cinttypes>
-#include <fstream>
 #include <memory>
 #include <string>
 
@@ -60,7 +60,7 @@ class ScsiHardDisk : public ScsiDevice {
     void rewind();
 
 private:
-    std::fstream    hdd_img;
+    ImgFile         hdd_img;
     uint64_t        img_size;
     int             total_blocks;
     uint64_t        file_offset = 0;