[lmi-commits] [lmi] master a074fd5 1/3: Document a contract and the measures taken to test it

[Greg Chicares]

branch: master
commit a074fd58340d7866028358a991ed2e3f61a44546
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Document a contract and the measures taken to test it
    
    Added an assertion to ensure that part of the contract is fulfilled.
    
    See:
      https://lists.nongnu.org/archive/html/lmi/2018-04/msg00090.html
---
 wx_table_generator.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/wx_table_generator.cpp b/wx_table_generator.cpp
index a38d0c4..ef630af 100644
--- a/wx_table_generator.cpp
+++ b/wx_table_generator.cpp
@@ -82,6 +82,8 @@ void wx_table_generator::add_column
     ,std::string const& widest_text
     )
 {
+    LMI_ASSERT(!column_widths_already_computed_);
+
     // There is no need to care about the column width for hidden columns.
     int width;
     if(header.empty())
@@ -193,7 +195,16 @@ wxRect wx_table_generator::text_rect(std::size_t column, 
int y)
 
 /// Compute column widths.
 ///
-/// This function is to be called exactly once. Reason...
+/// This function must be called after the last time add_column() is
+/// called, and before the first time that the column widths it sets
+/// are used. It is assumed to be fairly expensive, so that it should
+/// be called only once. There seems to be no simple way to impose
+/// those synchronization requirements upon clients, so
+///  - add_column() asserts that this function hasn't yet been called;
+///  - this function exits early if it has already been called.
+/// Thus, any violation of the first part of this contract is detected
+/// at run time. It is hoped that this function is called in enough
+/// places to fulfill the second part of the contract.
 
 void wx_table_generator::do_compute_column_widths()
 {