Introduce virDomainParseScaledValue

and use it for virDomainParseMemory. This allows to parse arbitrary
scaled value, not only memory related values as needed for the
filesystem limits code following later in this series.

src/conf/domain_conf.c

@@ -4138,6 +4138,63 @@ cleanup:
     goto cleanup;
 }
 
+
+/* Parse a value located at XPATH within CTXT, and store the
+ * result into val.  If REQUIRED, then the value must exist;
+ * otherwise, the value is optional.  The value is in bytes.
+ * Return 0 on success, -1 on failure after issuing error. */
+static int
+virDomainParseScaledValue(const char *xpath,
+                          xmlXPathContextPtr ctxt,
+                          unsigned long long *val,
+                          unsigned long long scale,
+                          unsigned long long max,
+                          bool required)
+{
+    char *xpath_full = NULL;
+    char *unit = NULL;
+    int ret = -1;
+    unsigned long long bytes;
+
+    *val = 0;
+    if (virAsprintf(&xpath_full, "string(%s)", xpath) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+    ret = virXPathULongLong(xpath_full, ctxt, &bytes);
+    if (ret < 0) {
+        if (ret == -2)
+            virDomainReportError(VIR_ERR_XML_ERROR,
+                                 _("could not parse element %s"),
+                                 xpath);
+        else if (required)
+            virDomainReportError(VIR_ERR_XML_ERROR,
+                                 _("missing element %s"),
+                                 xpath);
+        else
+            ret = 0;
+        goto cleanup;
+    }
+    VIR_FREE(xpath_full);
+
+    if (virAsprintf(&xpath_full, "string(%s/@unit)", xpath) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+    unit = virXPathString(xpath_full, ctxt);
+
+    if (virScaleInteger(&bytes, unit, scale, max) < 0)
+        goto cleanup;
+
+    *val = bytes;
+    ret = 0;
+cleanup:
+    VIR_FREE(xpath_full);
+    VIR_FREE(unit);
+    return ret;
+}
+
+
 /* Parse the XML definition for a disk
  * @param node XML nodeset to parse for disk definition
  */
@@ -7768,53 +7825,24 @@ static int
 virDomainParseMemory(const char *xpath, xmlXPathContextPtr ctxt,
                      unsigned long long *mem, bool required)
 {
-    char *xpath_full = NULL;
-    char *unit = NULL;
     int ret = -1;
-    unsigned long long bytes;
-    unsigned long long max;
+    unsigned long long bytes, max;
 
-    *mem = 0;
-    if (virAsprintf(&xpath_full, "string(%s)", xpath) < 0) {
-        virReportOOMError();
-        goto cleanup;
-    }
-    ret = virXPathULongLong(xpath_full, ctxt, &bytes);
-    if (ret < 0) {
-        if (ret == -2)
-            virDomainReportError(VIR_ERR_XML_ERROR,
-                                 _("could not parse memory element %s"),
-                                 xpath);
-        else if (required)
-            virDomainReportError(VIR_ERR_XML_ERROR,
-                                 _("missing memory element %s"),
-                                 xpath);
-        else
-            ret = 0;
-        goto cleanup;
-    }
-    VIR_FREE(xpath_full);
-
-    if (virAsprintf(&xpath_full, "string(%s/@unit)", xpath) < 0) {
-        virReportOOMError();
-        goto cleanup;
-    }
-    unit = virXPathString(xpath_full, ctxt);
     /* On 32-bit machines, our bound is 0xffffffff * KiB. On 64-bit
      * machines, our bound is off_t (2^63).  */
     if (sizeof(unsigned long) < sizeof(long long))
         max = 1024ull * ULONG_MAX;
     else
         max = LLONG_MAX;
-    if (virScaleInteger(&bytes, unit, 1024, max) < 0)
+
+    ret = virDomainParseScaledValue(xpath, ctxt, &bytes, 1024, max, required);
+    if (ret < 0)
         goto cleanup;
 
     /* Yes, we really do use kibibytes for our internal sizing.  */
     *mem = VIR_DIV_UP(bytes, 1024);
     ret = 0;
 cleanup:
-    VIR_FREE(xpath_full);
-    VIR_FREE(unit);
     return ret;
 }