Add saved file backups

gui-js/libs/shared/src/lib/backend/minsky.ts

@@ -1397,6 +1397,7 @@ export class Minsky extends CppClass {
   async multipleEquities(...args: any[]): Promise<boolean> {return this.$callMethod('multipleEquities',...args);}
   async nSteps(...args: number[]): Promise<number> {return this.$callMethod('nSteps',...args);}
   async nameCurrentItem(a1: string): Promise<void> {return this.$callMethod('nameCurrentItem',a1);}
+  async numBackups(...args: number[]): Promise<number> {return this.$callMethod('numBackups',...args);}
   async numOpArgs(a1: string): Promise<number> {return this.$callMethod('numOpArgs',a1);}
   async openGroupInCanvas(): Promise<void> {return this.$callMethod('openGroupInCanvas');}
   async openLogFile(a1: string): Promise<void> {return this.$callMethod('openLogFile',a1);}

model/minsky.cc

@@ -66,6 +66,8 @@
 #include <sys/sysinfo.h>
 #endif
 
+#include <stdio.h>
+
 using namespace classdesc;
 using namespace boost::posix_time;
 
@@ -1007,6 +1009,9 @@ namespace minsky
 
   void Minsky::save(const std::string& filename)
   {
+    // back up to temporary file name
+    rename(filename.c_str(), (filename+"~").c_str());
+
     const schema3::Minsky m(*this);
     Saver saver(filename);
     saver.packer.prettyPrint=true;
@@ -1015,15 +1020,24 @@ namespace minsky
         saver.save(m);
       }
     catch (...) {
+      // rename backup in place
+      rename((filename+"~").c_str(), filename.c_str());
       // if exception is due to file error, provide a more useful message
       if (!saver.os)
-        throw runtime_error("cannot save to "+filename);
+          throw runtime_error("cannot save to "+filename);
       throw;
     }
     flags &= ~is_edited;
     fileVersion=minskyVersion;
     if (autoSaver)
       boost::filesystem::remove(autoSaver->fileName);
+    // rotate saved versions
+    for (int i=numBackups; i>1; --i)
+      rename((filename+";"+to_string(i-1)).c_str(), (filename+";"+to_string(i)).c_str());
+    if (numBackups>0)
+      rename((filename+"~").c_str(), (filename+";1").c_str());
+    else
+      ::remove((filename+"~").c_str());
   }
 
   void Minsky::load(const std::string& filename) 

model/minsky.h

@@ -311,6 +311,7 @@ namespace minsky
     void reset(); ///<resets the variables back to their initial values
     std::vector<double> step();  ///< step the equations (by n steps, default 1)
 
+    int numBackups=1; ///< number of previous versions of saved files to keep
     /// save to a file
     void save(const std::string& filename);
     /// load from a file

test/00/saveBackups.sh

@@ -0,0 +1,50 @@
+#! /bin/sh
+
+here=`pwd`
+if test $? -ne 0; then exit 2; fi
+tmp=/tmp/$$
+mkdir $tmp
+if test $? -ne 0; then exit 2; fi
+cd $tmp
+if test $? -ne 0; then exit 2; fi
+
+fail()
+{
+    echo "FAILED" 1>&2
+    cd $here
+    chmod -R u+w $tmp
+    rm -rf $tmp
+    exit 1
+}
+
+pass()
+{
+    echo "PASSED" 1>&2
+    cd $here
+    chmod -R u+w $tmp
+    rm -rf $tmp
+    exit 0
+}
+
+trap "fail" 1 2 3 15
+cat >input.tcl <<EOF
+minsky.load $here/examples/exponentialGrowth.mky
+minsky.numBackups 3
+minsky.findObject "IntOp"
+for {set i 1} {\$i<10} {incr i} {
+  minsky.canvas.item.description "y\$i"
+  minsky.save foo.mky
+}
+tcl_exit
+EOF
+
+$here/gui-tk/minsky input.tcl
+if [ $? -ne 0 ]; then fail; fi
+
+if [ `grep "<name>y" foo.mky*|wc -l` -ne 4 ]; then fail; fi
+
+for i in 3 2 1; do
+    if ! grep "<name>y$[9-i]" "foo.mky;$i" >/dev/null; then fail; fi
+done
+
+pass