pixma: parse XML response sent by the scanner and present tips to the user

backend/Makefile.am

@@ -919,12 +919,12 @@ libpixma_la_SOURCES = pixma/pixma.c \
 	pixma/pixma_bjnp.h \
 	pixma/pixma_bjnp_private.h \
 	pixma/pixma_rename.h
-libpixma_la_CPPFLAGS = $(AM_CPPFLAGS) -DBACKEND_NAME=pixma
+libpixma_la_CPPFLAGS = $(AM_CPPFLAGS) $(XML_CFLAGS) -DBACKEND_NAME=pixma
 
 nodist_libsane_pixma_la_SOURCES = pixma-s.c
 libsane_pixma_la_CPPFLAGS = $(AM_CPPFLAGS) -DBACKEND_NAME=pixma
 libsane_pixma_la_LDFLAGS = $(DIST_SANELIBS_LDFLAGS)
-libsane_pixma_la_LIBADD = $(COMMON_LIBS) libpixma.la ../sanei/sanei_init_debug.lo ../sanei/sanei_constrain_value.lo ../sanei/sanei_config.lo  sane_strstatus.lo ../sanei/sanei_usb.lo ../sanei/sanei_thread.lo $(SANEI_SANEI_JPEG_LO) $(JPEG_LIBS) $(MATH_LIB) $(SOCKET_LIBS) $(USB_LIBS) $(SANEI_THREAD_LIBS) $(RESMGR_LIBS)
+libsane_pixma_la_LIBADD = $(COMMON_LIBS) libpixma.la ../sanei/sanei_init_debug.lo ../sanei/sanei_constrain_value.lo ../sanei/sanei_config.lo  sane_strstatus.lo ../sanei/sanei_usb.lo ../sanei/sanei_thread.lo $(SANEI_SANEI_JPEG_LO) $(JPEG_LIBS) $(XML_LIBS) $(MATH_LIB) $(SOCKET_LIBS) $(USB_LIBS) $(SANEI_THREAD_LIBS) $(RESMGR_LIBS)
 EXTRA_DIST += pixma.conf.in
 # included in pixma.c
 EXTRA_DIST += pixma/pixma_sane_options.c pixma/pixma_sane_options.h

backend/pixma/pixma_common.c

@@ -54,6 +54,12 @@
 #include <sys/time.h>		/* gettimeofday(4.3BSD) */
 #include <unistd.h>		/* usleep */
 
+#if defined(HAVE_LIBXML2)
+# include <libxml/parser.h>
+#else
+# error "The pixma backend requires libxml2"
+#endif
+
 #include "pixma_rename.h"
 #include "pixma_common.h"
 #include "pixma_io.h"
@@ -1213,3 +1219,97 @@ pixma_get_device_status (pixma_t * s, pixma_device_status_t * status)
   memset (status, 0, sizeof (*status));
   return s->ops->get_status (s, status);
 }
+
+static const char *
+format_xml_response(const char *resp_details)
+{
+  if (strcmp(resp_details, "DeviceBusy") == 0)
+    /* https://cromwell-intl.com/open-source/canon-pixma-printer-scanner.html */
+    return "DeviceBusy - Device not initialized (yet). " \
+      "Please check the USB power, try a different port or install the Ink Cartridges if the device supports them.";
+  else if (strcmp(resp_details, "ScannerCarriageLockError") == 0)
+    return "ScannerCarriageLockError - Please consult the manual to unlock the Carriage Lock.";
+  else if (strcmp(resp_details, "PCScanning") == 0)
+    return "PCScanning - Previous scan attempt was not completed. Try disconnecting and reconnecting the scanner. " \
+      "If the problem persists, consider reporting it as a bug at http://www.sane-project.org/bugs.html.";
+  else if (strcmp(resp_details, "DeviceCheckError") == 0)
+    return "DeviceCheckError - Device detected a fault. Contact the repair center.";
+  else
+    return resp_details;
+}
+
+int
+pixma_parse_xml_response(const char *xml_message)
+{
+  int status = PIXMA_EPROTO;
+  xmlDoc *doc = NULL;
+  xmlNode *node = NULL;
+  xmlChar *content = NULL;
+
+  doc = xmlReadMemory(xml_message, strlen(xml_message), "mem:device-resp.xml", NULL, 0);
+  if (doc == NULL) {
+    PDBG(pixma_dbg(10, "unable to parse xml response\n"));
+    status = PIXMA_EINVAL;
+    goto clean;
+  }
+
+  node = xmlDocGetRootElement(doc);
+  if (node == NULL) {
+    status = PIXMA_EPROTO;
+    goto clean;
+  }
+
+  /* /cmd */
+  for (; node; node = node->next) {
+    if (strcmp((const char*)node->name, "cmd") == 0)
+      break;
+  }
+  if (!node) {
+    status = PIXMA_EPROTO;
+    goto clean;
+  }
+
+  /* /cmd/contents */
+  for (node = node->children; node; node = node->next) {
+    if (strcmp((const char*)node->name, "contents") == 0)
+      break;
+  }
+  if (!node) {
+    status = PIXMA_EPROTO;
+    goto clean;
+  }
+
+  /* /cmd/contents/param_set */
+  for (node = node->children; node; node = node->next) {
+    if (strcmp((const char*)node->name, "param_set") == 0)
+      break;
+  }
+  if (!node) {
+    status = PIXMA_EPROTO;
+    goto clean;
+  }
+
+  /* /cmd/contents/param_set/response... */
+  for (node = node->children; node; node = node->next)
+  {
+    if (strcmp((const char*)node->name, "response") == 0) {
+      content = xmlNodeGetContent(node);
+      if (strcmp((const char*)content, "OK") == 0)
+        status = PIXMA_STATUS_OK;
+      else
+        status = PIXMA_EINVAL;
+      xmlFree(content);
+    } else if (strcmp((const char*)node->name, "response_detail") == 0) {
+      content = xmlNodeGetContent(node);
+      if (strlen((const char*)content) > 0) {
+        PDBG(pixma_dbg(0, "device response: %s\n",
+                      format_xml_response((const char*)content)));
+      }
+      xmlFree(content);
+    }
+  }
+
+clean:
+  xmlFreeDoc(doc);
+  return status;
+}

backend/pixma/pixma_common.h

@@ -205,6 +205,7 @@ uint8_t *pixma_newcmd (pixma_cmdbuf_t *, unsigned cmd,
 int pixma_exec (pixma_t *, pixma_cmdbuf_t *);
 int pixma_exec_short_cmd (pixma_t *, pixma_cmdbuf_t *, unsigned cmd);
 int pixma_map_status_errno (unsigned status);
+int pixma_parse_xml_response(const char *xml_message);
 /**@}*/
 
 #define pixma_fill_checksum(start, end) do {		\

backend/pixma/pixma_mp150.c

@@ -323,8 +323,6 @@
 <ivec:param_set servicetype=\"scan\"><ivec:jobID>00000001</ivec:jobID>\
 </ivec:param_set></ivec:contents></cmd>"
 
-#define XML_OK   "<ivec:response>OK</ivec:response>"
-
 enum mp150_state_t
 {
   state_idle,
@@ -462,7 +460,7 @@ send_xml_dialog (pixma_t * s, const char * xml_message)
   PDBG (pixma_dbg (10, "XML message sent to scanner:\n%s\n", xml_message));
   PDBG (pixma_dbg (10, "XML response back from scanner:\n%s\n", mp->cb.buf));
 
-  return (strcasestr ((const char *) mp->cb.buf, XML_OK) != NULL);
+  return pixma_parse_xml_response((const char*)mp->cb.buf) == PIXMA_STATUS_OK;
 }
 
 static int

backend/pixma/pixma_mp800.c

@@ -153,8 +153,6 @@
 <ivec:param_set servicetype=\"scan\"><ivec:jobID>00000001</ivec:jobID>\
 </ivec:param_set></ivec:contents></cmd>"
 
-#define XML_OK   "<ivec:response>OK</ivec:response>"
-
 enum mp810_state_t
 {
   state_idle,
@@ -294,7 +292,7 @@ static int send_xml_dialog (pixma_t * s, const char * xml_message)
   PDBG(pixma_dbg (10, "XML message sent to scanner:\n%s\n", xml_message));
   PDBG(pixma_dbg (10, "XML response back from scanner:\n%s\n", mp->cb.buf));
 
-  return (strcasestr ((const char *) mp->cb.buf, XML_OK) != NULL);
+  return pixma_parse_xml_response((const char*)mp->cb.buf) == PIXMA_STATUS_OK;
 }
 
 static void new_cmd_tpu_msg (pixma_t *s, pixma_cmdbuf_t * cb, uint16_t cmd)