<fix>(precompiled): fix bfs isExist bug. (#735)

Author: kyonRay

src/main/java/org/fisco/bcos/sdk/v3/contract/precompiled/bfs/BFSService.java

@@ -126,12 +126,13 @@ public Tuple2<BigInteger, List<BFSInfo>> listBFSInfo(
      */
     public BFSInfo isExist(String absolutePath) throws ContractException {
         PrecompiledVersionCheck.LS_PAGE_VERSION.checkVersion(currentVersion);
-        if (absolutePath.endsWith("/")) {
-            absolutePath = absolutePath.substring(0, absolutePath.length() - 1);
+        Tuple2<String, String> parentPathAndBaseName =
+                BFSUtils.getParentPathAndBaseName(absolutePath);
+        String parent = parentPathAndBaseName.getValue1();
+        String child = parentPathAndBaseName.getValue2();
+        if (BFSUtils.BFS_SYSTEM_PATH.contains(absolutePath)) {
+            return new BFSInfo(child, BFSUtils.BFS_TYPE_DIR);
         }
-        int index = absolutePath.lastIndexOf('/');
-        String parent = absolutePath.substring(0, index);
-        String child = absolutePath.substring(index + 1);
         int offset = 0;
         int limit = 500;
         while (true) {

src/main/java/org/fisco/bcos/sdk/v3/contract/precompiled/bfs/BFSUtils.java

@@ -0,0 +1,51 @@
+package org.fisco.bcos.sdk.v3.contract.precompiled.bfs;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.Stack;
+import org.fisco.bcos.sdk.v3.codec.datatypes.generated.tuples.generated.Tuple2;
+
+public class BFSUtils {
+    private BFSUtils() {}
+
+    public static final String BFS_TYPE_DIR = "directory";
+    public static final String BFS_TYPE_CON = "contract";
+    public static final String BFS_TYPE_LNK = "link";
+
+    public static final String BFS_ROOT = "/";
+    public static final String BFS_APPS = "/apps";
+    public static final String BFS_SYS = "/sys";
+    public static final String BFS_TABLES = "/tables";
+    public static final String BFS_USER = "/usr";
+
+    public static final Set<String> BFS_SYSTEM_PATH =
+            new HashSet<>(Arrays.asList(BFS_ROOT, BFS_APPS, BFS_SYS, BFS_TABLES, BFS_USER));
+
+    public static Tuple2<String, String> getParentPathAndBaseName(String path) {
+        if (path.equals("/")) return new Tuple2<>("/", "/");
+        List<String> path2Level = path2Level(path);
+        String baseName = path2Level.get(path2Level.size() - 1);
+        String parentPath = '/' + String.join("/", path2Level.subList(0, path2Level.size() - 1));
+        return new Tuple2<>(parentPath, baseName);
+    }
+
+    public static List<String> path2Level(String absolutePath) {
+        Stack<String> pathStack = new Stack<>();
+        for (String s : absolutePath.split("/")) {
+            if (s.isEmpty() || s.equals(".")) {
+                continue;
+            }
+            if (s.equals("..")) {
+                if (!pathStack.isEmpty()) {
+                    pathStack.pop();
+                }
+                continue;
+            }
+            pathStack.push(s);
+        }
+        return new ArrayList<>(pathStack);
+    }
+}