From 564379569c91890136ef6aa44f1a84bbb2237726 Mon Sep 17 00:00:00 2001
From: Michel Hidalgo <michel@ekumenlabs.com>
Date: Wed, 20 May 2020 09:52:47 -0300
Subject: [PATCH] Update ROS prefix utilities impl and tests.

Signed-off-by: Michel Hidalgo <michel@ekumenlabs.com>
---
 rmw_fastrtps_shared_cpp/src/namespace_prefix.cpp | 14 +++++++++-----
 rmw_fastrtps_shared_cpp/test/test_names.cpp      |  6 ++++++
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/rmw_fastrtps_shared_cpp/src/namespace_prefix.cpp b/rmw_fastrtps_shared_cpp/src/namespace_prefix.cpp
index e5bbd8fad..4945e8518 100644
--- a/rmw_fastrtps_shared_cpp/src/namespace_prefix.cpp
+++ b/rmw_fastrtps_shared_cpp/src/namespace_prefix.cpp
@@ -31,7 +31,7 @@ const std::vector<std::string> _ros_prefixes =
 std::string
 _resolve_prefix(const std::string & name, const std::string & prefix)
 {
-  if (!name.empty()) {
+  if (name.length() > prefix.length()) {
     if (name.rfind(prefix, 0) == 0 && name.at(prefix.length()) == '/') {
       return name.substr(prefix.length());
     }
@@ -44,8 +44,10 @@ std::string
 _get_ros_prefix_if_exists(const std::string & topic_name)
 {
   for (const auto & prefix : _ros_prefixes) {
-    if (topic_name.rfind(prefix, 0) == 0 && topic_name.at(prefix.length()) == '/') {
-      return prefix;
+    if (topic_name.length() > prefix.length()) {
+      if (topic_name.rfind(prefix, 0) == 0 && topic_name.at(prefix.length()) == '/') {
+        return prefix;
+      }
     }
   }
   return "";
@@ -56,8 +58,10 @@ std::string
 _strip_ros_prefix_if_exists(const std::string & topic_name)
 {
   for (const auto & prefix : _ros_prefixes) {
-    if (topic_name.rfind(prefix, 0) == 0 && topic_name.at(prefix.length()) == '/') {
-      return topic_name.substr(prefix.length());
+    if (topic_name.length() > prefix.length()) {
+      if (topic_name.rfind(prefix, 0) == 0 && topic_name.at(prefix.length()) == '/') {
+        return topic_name.substr(prefix.length());
+      }
     }
   }
   return topic_name;
diff --git a/rmw_fastrtps_shared_cpp/test/test_names.cpp b/rmw_fastrtps_shared_cpp/test/test_names.cpp
index 64b00794e..6be353ee6 100644
--- a/rmw_fastrtps_shared_cpp/test/test_names.cpp
+++ b/rmw_fastrtps_shared_cpp/test/test_names.cpp
@@ -23,8 +23,10 @@ TEST(NamespaceTest, get_prefix) {
   EXPECT_EQ("", _get_ros_prefix_if_exists(""));
   EXPECT_EQ("", _get_ros_prefix_if_exists("not/a_ros_prefix"));
   for (const auto & prefix : _get_all_ros_prefixes()) {
+    EXPECT_EQ("", _get_ros_prefix_if_exists(prefix));
     EXPECT_EQ("", _get_ros_prefix_if_exists(prefix + "_should_not_match"));
     EXPECT_EQ("", _get_ros_prefix_if_exists("th/is_should_not_match/" + prefix));
+    EXPECT_EQ(prefix, _get_ros_prefix_if_exists(prefix + "/"));
     EXPECT_EQ(prefix, _get_ros_prefix_if_exists(prefix + "/should_match"));
   }
 }
@@ -33,6 +35,8 @@ TEST(NamespaceTest, strip_prefix) {
   EXPECT_EQ("", _strip_ros_prefix_if_exists(""));
   EXPECT_EQ("/no_ros_prefix/test", _strip_ros_prefix_if_exists("/no_ros_prefix/test"));
   for (const auto & prefix : _get_all_ros_prefixes()) {
+    EXPECT_EQ(prefix, _strip_ros_prefix_if_exists(prefix));
+    EXPECT_EQ("/", _strip_ros_prefix_if_exists(prefix + "/"));
     EXPECT_EQ(
       prefix + "should_not_be_stripped",
       _strip_ros_prefix_if_exists(prefix + "should_not_be_stripped"));
@@ -48,6 +52,8 @@ TEST(NamespaceTest, resolve_prefix) {
   EXPECT_EQ("", _resolve_prefix("", "some_ros_prefix"));
   EXPECT_EQ("", _resolve_prefix("/test", "some_ros_prefix"));
   EXPECT_EQ("/test", _resolve_prefix("/test", ""));
+  EXPECT_EQ("", _resolve_prefix("some_ros_prefix", "some_ros_prefix"));
+  EXPECT_EQ("/", _resolve_prefix("some_ros_prefix/", "some_ros_prefix"));
   EXPECT_EQ(
     "/test_some_ros_prefix",
     _resolve_prefix("some_ros_prefix/test_some_ros_prefix", "some_ros_prefix"));