Avoid removing wasi-nn temp directory when specified (#2465)

Since downloading the wasi-nn artifacts take a bit of time, the example script's first argument serves as a directory to reuse for running this script. This change cleans up temporary directories only when a directory was not specified.

ci/run-wasi-nn-example.sh

@@ -8,6 +8,15 @@
 set -e
 WASMTIME_DIR=$(dirname "$0" | xargs dirname)
 FIXTURE=https://gist.github.com/abrown/c7847bf3701f9efbb2070da1878542c1/raw/07a9f163994b0ff8f0d7c5a5c9645ec3d8b24024
+if [ -z "${1+x}" ]; then
+    # If no temporary directory is specified, create one.
+    TMP_DIR=$(mktemp -d -t ci-XXXXXXXXXX)
+    REMOVE_TMP_DIR=1
+else
+    # If a directory was specified, use it and avoid removing it.
+    TMP_DIR=$(realpath $1)
+    REMOVE_TMP_DIR=0
+fi
 
 # Inform the environment of OpenVINO library locations. Then we use OPENVINO_INSTALL_DIR below to avoid building all of
 # OpenVINO from source (quite slow).
@@ -17,7 +26,6 @@ source /opt/intel/openvino/bin/setupvars.sh
 OPENVINO_INSTALL_DIR=/opt/intel/openvino cargo build -p wasmtime-cli --features wasi-nn
 
 # Download all necessary test fixtures to the temporary directory.
-TMP_DIR=${1:-$(mktemp -d -t ci-XXXXXXXXXX)}
 wget --no-clobber --directory-prefix=$TMP_DIR $FIXTURE/frozen_inference_graph.bin
 wget --no-clobber --directory-prefix=$TMP_DIR $FIXTURE/frozen_inference_graph.xml
 wget --no-clobber --directory-prefix=$TMP_DIR $FIXTURE/tensor-1x3x300x300-f32.bgr
@@ -31,5 +39,7 @@ popd
 # Run the example in Wasmtime (note that the example uses `fixture` as the expected location of the model/tensor files).
 OPENVINO_INSTALL_DIR=/opt/intel/openvino cargo run --features wasi-nn -- run --mapdir fixture::$TMP_DIR $TMP_DIR/wasi-nn-example.wasm
 
-# Clean up.
-rm -rf $TMP_DIR
+# Clean up the temporary directory only if it was not specified (users may want to keep the directory around).
+if [[ $REMOVE_TMP_DIR -eq 1 ]]; then
+    rm -rf $TMP_DIR
+fi