Add libiberty/concat styled concat_path function

    This commit adds concat_path function to concatenate an arbitrary number of
    path elements.  The function automatically adds an directory separator between
    two elements as needed.

    gdb/ChangeLog:

	* common/common-utils.h (endswith): New function.
	* utils.c (_concat_path, approx_path_length): New function.
	* utils.h (_concat_path): New export.
	(concat_path): New define.

diff --git a/gdb/common/common-utils.h b/gdb/common/common-utils.h
index 618d2663fab881aa8636318f855fad1fd84ef304..47fdeeb79e8250c8f49b4747fb0eeb7ca5c52f7c 100644 (file)
--- a/gdb/common/common-utils.h
+++ b/gdb/common/common-utils.h
@@ -83,6 +83,17 @@ startswith (const char *string, const char *pattern)
   return strncmp (string, pattern, strlen (pattern)) == 0;
 }
 
+/* Return non-zero if the end of STRING matches PATTERN, zero
+   otherwise.  */
+
+static inline int
+endswith (const char *string, const char *pattern)
+{
+  return (strlen (string) > strlen (pattern)
+         && strncmp (string + strlen (string) - strlen (pattern), pattern,
+                     strlen (pattern)) == 0);
+}
+
 ULONGEST strtoulst (const char *num, const char **trailer, int base);
 
 /* Skip leading whitespace characters in INP, returning an updated

diff --git a/gdb/utils.c b/gdb/utils.c
index 2b947aad175f3f3c2986cc492de360ec0fce941d..11038500ab45b249f7842cfdd109210bf7e9c0e6 100644 (file)
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3179,6 +3179,52 @@ substitute_path_component (std::string &str, const std::string &from,
     }
 }
 
+/* Approximate length of final path.  Helper for concat_path.  */
+
+static inline unsigned long
+approx_path_length (std::initializer_list<std::string> args,
+                  std::string dir_separator)
+{
+  size_t length = 0;
+
+  for (const std::string &arg: args)
+      length += arg.length () + dir_separator.length ();
+
+  return length;
+}
+
+/* See utils.h.  */
+
+std::string
+_concat_path (std::initializer_list<std::string> args,
+             std::string dir_separator)
+{
+  std::string dst;
+  dst.reserve (approx_path_length (args, dir_separator));
+
+  for (const std::string &arg : args)
+    {
+      if (arg.empty ())
+       continue;
+
+      if (startswith (arg.c_str (), dir_separator.c_str ())
+         && endswith (dst.c_str (), dir_separator.c_str ()))
+       dst.erase (dst.length () - dir_separator.length (),
+                  dir_separator.length ());
+
+      else if (!dst.empty ()
+              && !startswith (arg.c_str (), dir_separator.c_str ())
+              && !endswith (dst.c_str (), dir_separator.c_str ())
+              && dst != TARGET_SYSROOT_PREFIX)
+       dst += dir_separator;
+
+      dst += arg;
+    }
+
+  dst.shrink_to_fit ();
+  return dst;
+}
+
 #ifdef HAVE_WAITPID
 
 #ifdef SIGALRM

diff --git a/gdb/utils.h b/gdb/utils.h
index d32114edb6e003d64199ab2cbce0f503df00328c..d9dbaec9038b1bce4e1b5a2bfb8368996df30356 100644 (file)
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -24,6 +24,7 @@
 #include "exceptions.h"
 #include "common/scoped_restore.h"
 #include <chrono>
+#include <string>
 
 extern void initialize_utils (void);
 
@@ -140,6 +141,22 @@ extern void substitute_path_component (std::string &str,
                                       const std::string &from,
                                       const std::string &to);
 
+/* Concatenate an arbitrary number of path elements.  Adds and removes
+   directory separators as needed.
+
+   concat_path (/first, second)                => /first/second
+   concat_path (first, second)         => first/second
+   concat_path (first/, second)                => first/second
+   concat_path (first, /second)                => first/second
+   concat_path (first/, /second)       => first/second
+   concat_path (target:, second)       => target:second
+   */
+
+extern std::string _concat_path (std::initializer_list<std::string> args,
+                                std::string dir_separator);
+
+#define concat_path(...) _concat_path ({__VA_ARGS__}, SLASH_STRING)
+
 char *ldirname (const char *filename);
 
 extern int count_path_elements (const char *path);