Bug #638543: Make the various counter formats configurable.

Patch by Matthijs Kooijman:

This retrieves the counter formats from the kvp slots in the book. The
defaults are unchanged, so this should not affect existing books at all.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@20055 57a11ea4-9604-0410-9ed3-97b8803252fd

src/engine/kvp_doc.txt

@@ -175,6 +175,20 @@ Use:  Holders for a bunch of counters for various types.  Used specifically
       that follows /counters/, e.g. "/counters/GncCustomer"
 \endverbatim      
 
+\verbatim
+Name: /counter_formats/...
+Type: string
+Entities: Book
+Use:  Holders for a bunch of counter formats for various types.  Used
+	  specifically in the business objects, to format a counter value
+	  into a (string) ID.  The counter name is the path that follows
+	  /counter_formats/, e.g. "/counter_formats/GncCustomer"
+
+	  These formats are printf-style format strings that contain exactly
+	  one format specifier for an int64 (optionally preceded or followed
+	  by arbitrary other strings).
+\endverbatim
+
 \subsection kvpD D
 
 \subsection kvpE E

src/libqof/qof/qofbook.c

@@ -436,6 +436,7 @@ qof_book_increment_and_format_counter (QofBook *book, const char *counter_name)
     KvpFrame *kvp;
     KvpValue *value;
     gint64 counter;
+    gchar* format;
 
     if (!book)
     {
@@ -476,8 +477,58 @@ qof_book_increment_and_format_counter (QofBook *book, const char *counter_name)
     qof_book_mark_dirty(book);
     qof_book_commit_edit(book);
 
+    format = qof_book_get_counter_format(book, counter_name);
+
+    if (!format)
+    {
+        PWARN("Cannot get format for counter");
+        return NULL;
+    }
+
     /* Generate a string version of the counter */
-    return g_strdup_printf ("%.6" G_GINT64_FORMAT, counter);
+    return g_strdup_printf(format, counter);
+}
+
+gchar *
+qof_book_get_counter_format(const QofBook *book, const char *counter_name)
+{
+    KvpFrame *kvp;
+    gchar *format;
+    KvpValue *value;
+
+    if (!book)
+    {
+        PWARN ("No book!!!");
+        return NULL;
+    }
+
+    if (!counter_name || *counter_name == '\0')
+    {
+        PWARN ("Invalid counter name.");
+        return NULL;
+    }
+
+    /* Get the KVP from the current book */
+    kvp = qof_book_get_slots (book);
+
+    if (!kvp)
+    {
+        PWARN ("Book has no KVP_Frame");
+        return NULL;
+    }
+
+    /* Get the format string */
+    value = kvp_frame_get_slot_path (kvp, "counter_formats", counter_name, NULL);
+    if (value)
+    {
+        format = kvp_value_get_string (value);
+    }
+    else
+    {
+        /* Use the default format */
+        format = "%.6" G_GINT64_FORMAT;
+    }
+    return format;
 }
 
 /* Determine whether this book uses trading accounts */

src/libqof/qof/qofbook.h

@@ -289,6 +289,12 @@ gint64 qof_book_get_counter (QofBook *book, const char *counter_name);
  */
 gchar *qof_book_increment_and_format_counter (QofBook *book, const char *counter_name);
 
+/** Get the format string to use for the named counter.
+ *    The return value is NULL on error or the format string of the
+ *    counter. The string should not be freed.
+ */
+gchar *qof_book_get_counter_format (const QofBook *book, const char *counter_name);
+
 const char* qof_book_get_string_option(const QofBook* book, const char* opt_name);
 void qof_book_set_string_option(QofBook* book, const char* opt_name, const char* opt_val);