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+/* channel.c -- device communication channel
+ * Copyright (C) 2008, 2009, 2013 SEIKO EPSON CORPORATION
+ *
+ * License: GPLv2+|iscan
+ * Authors: AVASYS CORPORATION
+ *
+ * This file is part of the SANE backend distributed with Image Scan!
+ *
+ * Image Scan!'s SANE backend 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 ought to have received a copy of the GNU General Public License
+ * along with this package. If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Linking Image Scan!'s SANE backend statically or dynamically with
+ * other modules is making a combined work based on this SANE backend.
+ * Thus, the terms and conditions of the GNU General Public License
+ * cover the whole combination.
+ *
+ * As a special exception, the copyright holders of Image Scan!'s SANE
+ * backend give you permission to link Image Scan!'s SANE backend with
+ * SANE frontends that communicate with Image Scan!'s SANE backend
+ * solely through the SANE Application Programming Interface,
+ * regardless of the license terms of these SANE frontends, and to
+ * copy and distribute the resulting combined work under terms of your
+ * choice, provided that every copy of the combined work is
+ * accompanied by a complete copy of the source code of Image Scan!'s
+ * SANE backend (the version of Image Scan!'s SANE backend used to
+ * produce the combined work), being distributed under the terms of
+ * the GNU General Public License plus this exception. An independent
+ * module is a module which is not derived from or based on Image
+ * Scan!'s SANE backend.
+ *
+ * As a special exception, the copyright holders of Image Scan!'s SANE
+ * backend give you permission to link Image Scan!'s SANE backend with
+ * independent modules that communicate with Image Scan!'s SANE
+ * backend solely through the "Interpreter" interface, regardless of
+ * the license terms of these independent modules, and to copy and
+ * distribute the resulting combined work under terms of your choice,
+ * provided that every copy of the combined work is accompanied by a
+ * complete copy of the source code of Image Scan!'s SANE backend (the
+ * version of Image Scan!'s SANE backend used to produce the combined
+ * work), being distributed under the terms of the GNU General Public
+ * License plus this exception. An independent module is a module
+ * which is not derived from or based on Image Scan!'s SANE backend.
+ *
+ * Note that people who make modified versions of Image Scan!'s SANE
+ * backend are not obligated to grant special exceptions for their
+ * modified versions; it is their choice whether to do so. The GNU
+ * General Public License gives permission to release a modified
+ * version without this exception; this exception also makes it
+ * possible to release a modified version which carries forward this
+ * exception.
+ */
+
+
+/*! \file
+ \brief Implements a hardware communication channel.
+
+ Hardware channels supported are usb, scsi and parallel.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#define USE_PROTECTED_CHANNEL_API
+#include "channel.h"
+
+#include "utils.h"
+
+extern channel *
+channel_net_ctor (channel *self, const char *dev_name, SANE_Status *status);
+
+extern channel *
+channel_pio_ctor (channel *self, const char *dev_name, SANE_Status *status);
+
+extern channel *
+channel_scsi_ctor (channel *self, const char *dev_name, SANE_Status *status);
+
+extern channel *
+channel_usb_ctor (channel *self, const char *dev_name, SANE_Status *status);
+
+extern channel *
+channel_interpreter_ctor (channel *self,
+ const char *dev_name, SANE_Status *status);
+
+
+#include <string.h>
+
+#include "epkowa_ip.h"
+
+#include "hw-data.h"
+
+
+/*! A ::channel factory method.
+ *
+ * Creates and initializes a channel object to match a \a dev_name.
+ *
+ * \todo Validate \a dev_name?
+ */
+channel *
+channel_create (const char *dev_name, SANE_Status *status)
+{
+ channel *ch = NULL;
+
+ require (dev_name);
+
+ if (status) *status = SANE_STATUS_GOOD;
+
+ ch = t_calloc (1, channel);
+ if (!ch)
+ {
+ if (status) *status = SANE_STATUS_NO_MEM;
+ return NULL;
+ }
+
+ ch->dtor = channel_dtor;
+ ch->is_open = channel_is_open;
+ ch->max_request_size = channel_max_request_size;
+ ch->set_max_request_size = channel_set_max_request_size;
+
+ ch->fd = -1;
+ ch->id = 0;
+ ch->max_size = 32 * 1024;
+
+ if (0 == strncmp_c (dev_name, "net:", strlen ("net:")))
+ {
+ ch->ctor = channel_net_ctor;
+ ch->type = CHAN_NET;
+ }
+ if (0 == strncmp_c (dev_name, "pio:", strlen ("pio:")))
+ {
+ ch->ctor = channel_pio_ctor;
+ ch->type = CHAN_PIO;
+ }
+ if (0 == strncmp_c (dev_name, "scsi:", strlen ("scsi:")))
+ {
+ ch->ctor = channel_scsi_ctor;
+ ch->type = CHAN_SCSI;
+ }
+ if (0 == strncmp_c (dev_name, "usb:", strlen ("usb:")))
+ {
+ ch->ctor = channel_usb_ctor;
+ ch->type = CHAN_USB;
+ }
+ if (0 == strncmp_c (dev_name, "interpreter:", strlen ("interpreter:")))
+ {
+ ch->ctor = channel_interpreter_ctor;
+ ch->type = CHAN_INTERP;
+ }
+
+ if (!ch->ctor)
+ {
+ err_major ("unsupported channel for '%s'", dev_name);
+ if (status) *status = SANE_STATUS_UNSUPPORTED;
+ delete (ch);
+ return NULL;
+ }
+
+ return ch->ctor (ch, dev_name, status);
+}
+
+/*! Logging wrapper around a channel's send() method.
+ */
+ssize_t
+channel_send (channel* ch, const void *buffer, size_t size,
+ SANE_Status *status)
+{
+ ssize_t n = 0;
+
+ log_call ("(%zd)", size);
+ dbg_hex (buffer, size);
+
+ n = ch->send (ch, buffer, size, status);
+
+ log_call ("transferred %zd bytes", n);
+ return n;
+}
+
+/*! Logging wrapper around a channel's recv() method.
+ */
+ssize_t
+channel_recv (channel *ch, void *buffer, size_t size, SANE_Status *status)
+{
+ ssize_t n = 0;
+
+ log_call ("(%zd)", size);
+
+ if (size < 256)
+ memset (buffer, 0x00, size);
+
+ n = ch->recv (ch, buffer, size, status);
+
+ if (0 < n)
+ {
+ if (size < 256)
+ { dbg_hex (buffer, n); }
+ else
+ { dbg_img (buffer, n); }
+ }
+
+ log_call ("transferred %zd bytes", n);
+ return n;
+}
+
+/*! Throttle the number of bytes read in a single go
+ */
+static ssize_t
+channel_recv_throttle (channel *ch, void *buffer, size_t size,
+ SANE_Status *status)
+{
+ size_t max = ch->max_request_size (ch);
+ return ch->recv (ch, buffer, size < max ? size : max, status);
+}
+
+ssize_t channel_recv_all (channel *ch, void *buffer,
+ size_t size, SANE_Status *status)
+{
+ return channel_recv_all_retry (ch, buffer, size, 1, status);
+}
+
+ssize_t
+channel_recv_all_retry (channel *ch, void *buffer, size_t size,
+ size_t max_attempts, SANE_Status *status)
+{
+ SANE_Status s = SANE_STATUS_GOOD;
+
+ ssize_t n = 0;
+ ssize_t t = 0;
+ size_t attempts = 0;
+
+ log_call ("(%zd)", size);
+
+ while (n < size && attempts < max_attempts)
+ {
+ t = channel_recv_throttle (ch, buffer + n, size - n, &s);
+ if (SANE_STATUS_GOOD != s || 0 >= t)
+ {
+ ++attempts;
+ log_info ("attempts: %zd/%zd", attempts, max_attempts);
+ }
+ if (0 < t) n += t;
+ log_call ("transferred %zd bytes, total %zd/%zd", t, n, size);
+ }
+
+ if (0 < n)
+ {
+ if (size < 256)
+ { dbg_hex (buffer, n); }
+ else
+ { dbg_img (buffer, n); }
+ }
+
+ if (status) *status = s;
+
+ return n;
+}
+
+/*! Tells whether a channel is ready to send() and recv() data.
+ */
+bool
+channel_is_open (const struct channel *self)
+{
+ return (self && 0 <= self->fd);
+}
+
+/*! Indicates the maximum number of bytes the channel should read
+ * in a singe request.
+ */
+size_t
+channel_max_request_size (const struct channel *self)
+{
+ require (self);
+
+ return self->max_size;
+}
+
+/*! Change the maximum number of bytes a channel should read in a
+ * single request.
+ */
+void
+channel_set_max_request_size (struct channel *self, size_t size)
+{
+ require (self);
+
+ self->max_size = size;
+}
+
+/*! "Base class" destructor.
+ */
+channel *
+channel_dtor (struct channel *self)
+{
+ SANE_Status status = SANE_STATUS_GOOD;
+
+ log_call ("(fd = %d)", self->fd);
+
+ if (!self) return NULL;
+
+ if (self->interpreter) self->interpreter->dtor (self);
+
+ if (self->is_open (self))
+ {
+ self->close (self, &status);
+ }
+
+ delete (self->name);
+ delete (self);
+
+ return NULL;
+}
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