Add rcutils_list_directory function

include/rcutils/filesystem.h

@@ -25,6 +25,7 @@ extern "C"
 
 #include "rcutils/allocator.h"
 #include "rcutils/macros.h"
+#include "rcutils/types.h"
 #include "rcutils/visibility_control.h"
 
 /// Return current working directory.
@@ -187,6 +188,27 @@ RCUTILS_PUBLIC
 size_t
 rcutils_get_file_size(const char * file_path);
 
+/// List the entries present in a directory.
+/**
+ * This function lists the name of each file or directory present in the given
+ * directory in an implementation-specific order.
+ *
+ * \param[in] directory_path The directory path to list the contents of.
+ * \param[in] allocator Allocator being used for resources in the string_array.
+ * \param[out] string_array The object to store the entries into.
+ * \return `RCUTILS_RET_OK` if successful, or
+ * \return `RCUTILS_RET_INVALID_ARGUMENT` for invalid arguments, or
+ * \return `RCUTILS_RET_BAD_ALLOC` if memory allocation fails, or
+ * \return `RCUTILS_RET_ERROR` if an unknown error occurs
+ */
+RCUTILS_PUBLIC
+RCUTILS_WARN_UNUSED
+rcutils_ret_t
+rcutils_list_directory(
+  const char * directory_path,
+  rcutils_allocator_t allocator,
+  rcutils_string_array_t * string_array);
+
 #ifdef __cplusplus
 }
 #endif

src/filesystem.c

@@ -32,7 +32,9 @@ extern "C"
 #endif  // _WIN32
 
 #include "rcutils/format_string.h"
+#include "rcutils/logging_macros.h"
 #include "rcutils/repl_str.h"
+#include "rcutils/strdup.h"
 
 #ifdef _WIN32
 # define RCUTILS_PATH_DELIMITER "\\"
@@ -225,11 +227,11 @@ rcutils_calculate_directory_size(const char * directory_path, rcutils_allocator_
   char * path = rcutils_join_path(directory_path, "*", allocator);
   WIN32_FIND_DATA data;
   HANDLE handle = FindFirstFile(path, &data);
+  allocator.deallocate(path, allocator.state);
   if (INVALID_HANDLE_VALUE == handle) {
     fprintf(stderr, "Can't open directory %s. Error code: %lu\n", directory_path, GetLastError());
     return dir_size;
   }
-  allocator.deallocate(path, allocator.state);
   if (handle != INVALID_HANDLE_VALUE) {
     do {
       // Skip over local folder handle (`.`) and parent folder (`..`)
@@ -275,6 +277,91 @@ rcutils_get_file_size(const char * file_path)
   return rc == 0 ? (size_t)(stat_buffer.st_size) : 0;
 }
 
+rcutils_ret_t
+rcutils_list_directory(
+  const char * directory_path,
+  rcutils_allocator_t allocator,
+  rcutils_string_array_t * string_array)
+{
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    directory_path, "directory_path is null", return RCUTILS_RET_INVALID_ARGUMENT);
+  RCUTILS_CHECK_FOR_NULL_WITH_MSG(
+    string_array, "string_array is null", return RCUTILS_RET_INVALID_ARGUMENT);
+
+  // Start with 8 entries
+  rcutils_ret_t ret = rcutils_string_array_init(string_array, 8, &allocator);
+  if (RCUTILS_RET_OK != ret) {
+    return ret;
+  }
+
+  size_t count = 0;
+
+#ifdef _WIN32
+  char * path = rcutils_join_path(directory_path, "*", allocator);
+  WIN32_FIND_DATA data;
+  HANDLE handle = FindFirstFile(path, &data);
+  allocator.deallocate(path, allocator.state);
+  if (INVALID_HANDLE_VALUE == handle) {
+    fprintf(stderr, "Can't open directory %s. Error code: %lu\n", directory_path, GetLastError());
+    ret = RCUTILS_RET_ERROR;
+    goto fail;
+  }
+  if (handle != INVALID_HANDLE_VALUE) {
+    do {
+      if (count >= string_array->size) {
+        ret = rcutils_string_array_resize(string_array, count * 2);
+        if (RCUTILS_RET_OK != ret) {
+          goto fail;
+        }
+      }
+
+      string_array->data[count] = rcutils_strdup(data.cFileName, allocator);
+      if (NULL == string_array->data[count]) {
+        goto fail;
+      }
+    } while (++count, FindNextFile(handle, &data));
+    FindClose(handle);
+  }
+#else
+  DIR * dir = opendir(directory_path);
+  if (NULL == dir) {
+    fprintf(stderr, "Can't open directory %s. Error code: %d\n", directory_path, errno);
+    ret = RCUTILS_RET_ERROR;
+    goto fail;
+  }
+  struct dirent * entry;
+  for (; NULL != (entry = readdir(dir)); ++count) {
+    if (count >= string_array->size) {
+      ret = rcutils_string_array_resize(string_array, count * 2);
+      if (RCUTILS_RET_OK != ret) {
+        goto fail;
+      }
+    }
+
+    string_array->data[count] = rcutils_strdup(entry->d_name, allocator);
+    if (NULL == string_array->data[count]) {
+      goto fail;
+    }
+  }
+  closedir(dir);
+#endif
+
+  // Shrink the array back down
+  if (count != string_array->size) {
+    ret = rcutils_string_array_resize(string_array, count);
+    if (RCUTILS_RET_OK == ret) {
+      return RCUTILS_RET_OK;
+    }
+  }
+
+fail:
+  if (RCUTILS_RET_OK != rcutils_string_array_fini(string_array)) {
+    RCUTILS_LOG_ERROR(
+      "failed to clean up on error (leaking memory): '%s'", rcutils_get_error_string().str);
+  }
+  return ret;
+}
+
 #ifdef __cplusplus
 }
 #endif

test/test_filesystem.cpp

@@ -15,10 +15,15 @@
 #include <gtest/gtest.h>
 #include <string>
 
+#include "rcutils/error_handling.h"
 #include "rcutils/filesystem.h"
 
 #include "osrf_testing_tools_cpp/scope_exit.hpp"
 
+#ifdef _WIN32
+  #define strdup _strdup
+#endif
+
 static rcutils_allocator_t g_allocator = rcutils_get_default_allocator();
 
 class TestFilesystemFixture : public ::testing::Test
@@ -373,3 +378,48 @@ TEST_F(TestFilesystemFixture, calculate_file_size) {
     g_allocator.deallocate(non_existing_path, g_allocator.state);
   });
 }
+
+TEST_F(TestFilesystemFixture, list_directory) {
+  char * path =
+    rcutils_join_path(this->test_path, "dummy_folder", g_allocator);
+  ASSERT_NE(nullptr, path);
+
+  rcutils_string_array_t actual_contents;
+  rcutils_ret_t ret = rcutils_list_directory(nullptr, g_allocator, &actual_contents);
+  EXPECT_EQ(RCUTILS_RET_INVALID_ARGUMENT, ret);
+  rcutils_reset_error();
+
+  ret = rcutils_list_directory(path, g_allocator, nullptr);
+  EXPECT_EQ(RCUTILS_RET_INVALID_ARGUMENT, ret);
+  rcutils_reset_error();
+
+  ret = rcutils_list_directory(path, g_allocator, &actual_contents);
+  ASSERT_EQ(RCUTILS_RET_OK, ret);
+  OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT(
+  {
+    if (RCUTILS_RET_OK != rcutils_string_array_fini(&actual_contents)) {
+      FAIL();
+    }
+  });
+
+  ret = rcutils_string_array_sort(&actual_contents);
+  ASSERT_EQ(RCUTILS_RET_OK, ret);
+
+  rcutils_string_array_t expected_contents;
+  ret = rcutils_string_array_init(&expected_contents, 3, &g_allocator);
+  ASSERT_EQ(RCUTILS_RET_OK, ret);
+  OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT(
+  {
+    if (RCUTILS_RET_OK != rcutils_string_array_fini(&expected_contents)) {
+      FAIL();
+    }
+  });
+  expected_contents.data[0] = strdup(".");
+  expected_contents.data[1] = strdup("..");
+  expected_contents.data[2] = strdup("dummy.dummy");
+
+  int res;
+  ret = rcutils_string_array_cmp(&expected_contents, &actual_contents, &res);
+  ASSERT_EQ(RCUTILS_RET_OK, ret);
+  EXPECT_EQ(0, res);
+}