run_scons: call scons from a bash script, for signals

and so, to call scons, we have a bash wrapper, run_scons.sh, which
creates two wrappers, valeNsconsM.bat and valeNsconsM.sh, and calls
the .bat, which then calls the .sh with bash, which then calls scons
with python.

The .bat layer is needed because we need to set up the Visual Studio
environment through vcvarsall.bat, which only works from within a .bat
file. Then, the .sh layer is needed so that UNIX signals (e.g. CTRL+C)
can be caught while running scons (which would be impossible if run
directly from the .bat)

Enjoy!

run_scons.sh

@@ -17,6 +17,7 @@ windows_scons_python_dir () {
       echo "ERROR: Python $SCONS_PYTHON_MAJOR_MINOR was not installed properly" >&2
       exit 1
     fi
+    PYDIR=$(cygpath -u "$PYDIR")
     echo "$PYDIR"
 }
 
@@ -72,33 +73,46 @@ is_windows () {
 if is_windows ; then
     VS_ENV_CMD=$(windows_setup_environment)
     pydir=$(windows_scons_python_dir)
+    pydir_w=$(cygpath -d "$pydir")
 
     # Instead of invoking cmd.exe /c, which would force us to
     # rely on its flaky semantics for double quotes,
     # we go through a batch file.
+
+    # The problem is that, if we run scons directly from within the
+    # .bat file (or, even worse, call scons.bat), then it will not
+    # capture UNIX signals (CTRL+C, etc.) So we need to go "back to
+    # Cygwin": create a .sh file, and have the .bat file call bash
+    # with the .sh file, and have the .sh file call python with scons.py
+    # instead of calling scons.bat.
+
+    # This detour through a .bat file is necessary because of
+    # vcvarsall.bat, which is called to change the caller's
+    # environment, which only works from a .bat file, and not from a
+    # bash script or python script.
+
     THIS_PID=$$
     # Find an unambiguous file name for our .bat file
     SCONS_EXECS=0
     while
-      SCONS_INVOKE_FILE="vale$THIS_PID""scons$SCONS_EXECS"".bat" &&
-      [[ -e "$SCONS_INVOKE_FILE" ]]
+      SCONS_INVOKE_FILE_BASENAME="vale$THIS_PID""scons$SCONS_EXECS" && {
+      [[ -e "$SCONS_INVOKE_FILE_BASENAME.bat" ]] ||
+      [[ -e "$SCONS_INVOKE_FILE_BASENAME.sh" ]]
+    }
     do
       SCONS_EXECS=$(($SCONS_EXECS + 1))
     done
     # Then create, run and remove the .bat file
-    cat > "$SCONS_INVOKE_FILE" <<EOF
+    cat > "$SCONS_INVOKE_FILE_BASENAME.bat" <<EOF
 call $VS_ENV_CMD
+C:\cygwin64\bin\bash.exe $SCONS_INVOKE_FILE_BASENAME.sh
 EOF
-    if command -v scons.bat > /dev/null 2>&1 ; then
-      echo "call scons.bat $cmd $parallel_opt" >> "$SCONS_INVOKE_FILE"
-    else
-      PYDIR=$(cygpath -d $(windows_scons_python_dir))
-      echo "$PYDIR/python.exe $PYDIR/Scripts/scons.py $*" >> "$SCONS_INVOKE_FILE"
-    fi
-    chmod +x "$SCONS_INVOKE_FILE"
-    "./$SCONS_INVOKE_FILE"
+    # TODO: convert arguments to scons to windows paths.
+    echo "$pydir/python.exe '$pydir_w\\Scripts\\scons.py' $*" > "$SCONS_INVOKE_FILE_BASENAME.sh"
+    chmod +x "$SCONS_INVOKE_FILE_BASENAME.bat"
+    "./$SCONS_INVOKE_FILE_BASENAME.bat"
     SCONS_RETCODE=$?
-    rm -f "$SCONS_INVOKE_FILE"
+    rm -f "$SCONS_INVOKE_FILE_BASENAME.bat" "$SCONS_INVOKE_FILE_BASENAME.sh"
     exit $SCONS_RETCODE
 else
     python$SCONS_PYTHON_MAJOR_MINOR $(which scons) "$@"