[gnumeric] CondFormat: make sure we have simple relative references

[Morten Welinder <mortenw src gnome org>]

commit ddfabad0a4560c62343a838d97e215f6d94ad1b3
Author: Morten Welinder <terra gnome org>
Date:   Mon Nov 30 20:43:40 2015 -0500

    CondFormat: make sure we have simple relative references
    
    This fixes #750271.

 NEWS               |    1 +
 src/dependent.c    |    6 +---
 src/xml-sax-read.c |   66 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 67 insertions(+), 6 deletions(-)
---
diff --git a/NEWS b/NEWS
index 4d30a9d..a603ec7 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,7 @@ Morten:
        * Fix TABLE problems.  [#752181]  [#752178]  [#752182]
        * Fuzzed file fixes.  [#752179]  [#752180]
        * Add R.DGUMBEL, R.PGUMBEL, R.QGUMBEL.
+       * Fix conditional format problem.  [#750271]
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.24
diff --git a/src/dependent.c b/src/dependent.c
index 7e00240..6d2e6fd 100644
--- a/src/dependent.c
+++ b/src/dependent.c
@@ -1393,16 +1393,14 @@ style_dep_unrender (GnmDependent *dep, const char *what)
        sheet_redraw_region (sheet,
                             pos->col, pos->row,
                             pos->col, pos->row);
-
-
 }
 
 static void
 style_dep_eval (GnmDependent *dep)
 {
        /*
-        * It is possible that the cell has been rendered between we ::changed
-        * was called.
+        * It is possible that the cell has been rendered between ::changed
+        * was called and now.
         */
        style_dep_unrender (dep, "being evaluated");
 }
diff --git a/src/xml-sax-read.c b/src/xml-sax-read.c
index 3dc0f93..d23eff5 100644
--- a/src/xml-sax-read.c
+++ b/src/xml-sax-read.c
@@ -45,6 +45,7 @@
 #include "cell.h"
 #include "position.h"
 #include "expr.h"
+#include "expr-impl.h"
 #include "expr-name.h"
 #include "print-info.h"
 #include "value.h"
@@ -1752,6 +1753,60 @@ xml_sax_condition_end (GsfXMLIn *xin, G_GNUC_UNUSED GsfXMLBlob *blob)
        state->cond = NULL;
 }
 
+/*
+ * We have saving expressions relative to A1.  This means that we read
+ * see a relative reference to a cell above as R[65535]C.  This function
+ * patches that to R[-1]C.
+ *
+ * We ought to fix the format, but then old Gnumerics couldn't read new
+ * files.  In fact, if we just added a "Position" attribute then we would
+ * get silent corruption.
+ */
+static GnmExpr const *
+cond_patchup (GnmExpr const *expr, GnmExprWalk *data)
+{
+       XMLSaxParseState *state = data->user;
+       GnmCellPos const *pos = &state->style_range.start;
+       if (GNM_EXPR_GET_OPER (expr) == GNM_EXPR_OP_CELLREF) {
+               GnmCellPos tpos;
+               GnmCellRef const *oref = &expr->cellref.ref;
+               GnmCellRef tref = *oref;
+               gnm_cellpos_init_cellref (&tpos, &expr->cellref.ref,
+                                         pos, state->sheet);
+               if (tref.col_relative)
+                       tref.col = tpos.col - pos->col;
+               if (tref.row_relative)
+                       tref.row = tpos.row - pos->row;
+               if (gnm_cellref_equal (&tref, oref))
+                       return NULL;
+               return gnm_expr_new_cellref (&tref);
+       } else if (GNM_EXPR_GET_OPER (expr) == GNM_EXPR_OP_CONSTANT &&
+                  VALUE_IS_CELLRANGE (expr->constant.value)) {
+               GnmRangeRef const *oref = value_get_rangeref (expr->constant.value);
+               GnmRangeRef tref = *oref;
+               GnmRange trange;
+               Sheet *start_sheet, *end_sheet;
+               GnmEvalPos ep;
+
+               eval_pos_init_pos (&ep, state->sheet, pos);
+               gnm_rangeref_normalize (oref, &ep, &start_sheet, &end_sheet,
+                                       &trange);
+               if (tref.a.col_relative)
+                       tref.a.col = trange.start.col - pos->col;
+               if (tref.a.row_relative)
+                       tref.a.row = trange.start.row - pos->row;
+               if (tref.b.col_relative)
+                       tref.b.col = trange.end.col - pos->col;
+               if (tref.b.row_relative)
+                       tref.b.row = trange.end.row - pos->row;
+               if (gnm_rangeref_equal (&tref, oref))
+                       return NULL;
+               return gnm_expr_new_constant (value_new_cellrange_unsafe (&tref.a, &tref.b));
+       }
+
+       return NULL;
+}
+
 static void
 xml_sax_condition_expr_end (GsfXMLIn *xin, G_GNUC_UNUSED GsfXMLBlob *blob)
 {
@@ -1760,17 +1815,24 @@ xml_sax_condition_expr_end (GsfXMLIn *xin, G_GNUC_UNUSED GsfXMLBlob *blob)
        int const i = xin->node->user_data.v_int;
        GnmExprTop const *texpr;
        GnmParsePos pos;
+       GnmExpr const *patched_expr;
 
        g_return_if_fail (gnm_style_cond_get_expr (state->cond, i) == NULL);
 
+       parse_pos_init_sheet (&pos, state->sheet);
        texpr = gnm_expr_parse_str (xin->content->str,
-                                   parse_pos_init_sheet (&pos, state->sheet),
+                                   &pos,
                                    GNM_EXPR_PARSE_DEFAULT,
                                    state->convs,
                                    NULL);
-
        g_return_if_fail (texpr != NULL);
 
+       patched_expr = gnm_expr_walk (texpr->expr, cond_patchup, state);
+       if (patched_expr) {
+               gnm_expr_top_unref (texpr);
+               texpr = gnm_expr_top_new (patched_expr);
+       }
+
        gnm_style_cond_set_expr (state->cond, texpr, i);
        gnm_expr_top_unref (texpr);
 }