edksetup.sh: Ensure that WORKSPACE points to the top of an edk2 checkout

Since WORKSPACE should point at the EDK2 tree, the right place
to check its validity is edksetup.sh, not BaseTools/BuildEnv.

This patch makes sure that BuildEnv is always invoked with a valid
WORKSPACE.  This lets us show better error messages, and ensures that
we never dirty the user's environment.

BuildEnv will maintain backwards-compatibility and, should the variable
be missing, it will be able to set a default WORKSPACE.  Only the sanity
checks will be of lower quality.

Note that the error message in SetupEnv will never be shown if
SetWorkspace sets WORKSPACE=`pwd`.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15701 6f19259b-4bc3-4df7-8a09-765794883524

edksetup.sh

@@ -33,16 +33,57 @@ function HelpMsg()
   return 1
 }
 
+function SetWorkspace()
+{
+  #
+  # If WORKSPACE is already set, then we can return right now
+  #
+  if [ -n "$WORKSPACE" ]
+  then
+    return 0
+  fi
+
+  if [ ! ${BASH_SOURCE[0]} -ef ./edksetup.sh ]
+  then
+    echo Run this script from the base of your tree.  For example:
+    echo "  cd /Path/To/Edk/Root"
+    echo "  . edksetup.sh"
+    return 1
+  fi
+
+  #
+  # Check for BaseTools/BuildEnv before dirtying the user's environment.
+  #
+  if [ ! -f BaseTools/BuildEnv ] && [ -z "$EDK_TOOLS_PATH" ]
+  then
+    echo BaseTools not found in your tree, and EDK_TOOLS_PATH is not set.
+    echo Please point EDK_TOOLS_PATH at the directory that contains
+    echo the EDK2 BuildEnv script.
+    return 1
+  fi
+
+  #
+  # Set $WORKSPACE
+  #
+  export WORKSPACE=`pwd`
+
+  return 0
+}
+
 function SetupEnv()
 {
   if [ -n "$EDK_TOOLS_PATH" ]
   then
     . $EDK_TOOLS_PATH/BuildEnv $*
-  elif [ -n "$WORKSPACE" ]
+  elif [ -f "$WORKSPACE/BaseTools/BuildEnv" ]
   then
     . $WORKSPACE/BaseTools/BuildEnv $*
   else
-    . BaseTools/BuildEnv $*
+    echo BaseTools not found in your tree, and EDK_TOOLS_PATH is not set.
+    echo Please check that WORKSPACE is not set incorrectly in your
+    echo shell, or point EDK_TOOLS_PATH at the directory that contains
+    echo the EDK2 BuildEnv script.
+    return 1
   fi
 }
 
@@ -56,6 +97,7 @@ function SourceEnv()
   then
     HelpMsg
   else
+    SetWorkspace &&
     SetupEnv "$*"
   fi
 }