From 9c48f72f02e3112f4193cc8b3f12b135aa483de1 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 11 Sep 2009 15:58:51 +0000
Subject: [PATCH] Make Path behave more consistently by always starting
 relative paths with a dot Treat out-of-range index to Path::operator[] as an
 error Change argv0 parameter of get_sys_*_dir to std::string

---
 source/dir.cpp  | 10 +++++-----
 source/dir.h    |  4 ++--
 source/path.cpp | 20 +++++++++++++-------
 source/path.h   |  5 +++++
 4 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/source/dir.cpp b/source/dir.cpp
index 09a89f1..29c24c1 100644
--- a/source/dir.cpp
+++ b/source/dir.cpp
@@ -32,15 +32,15 @@ namespace
 Helper function to determine the location of the program's executable.  Caches
 the last result to cut down filesystem access with repeated calls.
 */
-const Path &get_bin_dir(const Path &argv0)
+const Path &get_bin_dir(const string &argv0)
 {
-	static Path last_argv0;
+	static string last_argv0;
 	static Path bin_dir;
 
 	if(!(argv0==last_argv0))
 	{
 		Path exe;
-		if(argv0.size()==1)
+		if(argv0.find('/')==string::npos)
 		{
 			const char *path=getenv("PATH");
 			vector<string> dirs=split(path, ':');
@@ -184,7 +184,7 @@ Path get_user_data_dir(const string &appname)
 #endif
 }
 
-Path get_sys_conf_dir(const Path &argv0)
+Path get_sys_conf_dir(const string &argv0)
 {
 	Path dir=get_bin_dir(argv0);
 
@@ -199,7 +199,7 @@ Path get_sys_conf_dir(const Path &argv0)
 		return dir;
 }
 
-Path get_sys_data_dir(const Path &argv0, const string &appname)
+Path get_sys_data_dir(const string &argv0, const string &appname)
 {
 	Path dir=get_bin_dir(argv0);
 
diff --git a/source/dir.h b/source/dir.h
index 30ef33d..ebbe56c 100644
--- a/source/dir.h
+++ b/source/dir.h
@@ -43,10 +43,10 @@ Path get_home_dir();
 Path get_user_data_dir(const std::string &appname);
 
 /// Returns a directory containing system-wide configuration
-Path get_sys_conf_dir(const Path &argv0);
+Path get_sys_conf_dir(const std::string &argv0);
 
 /// Returns a directory containing immutable system-wide data
-Path get_sys_data_dir(const Path &argv0, const std::string &appname);
+Path get_sys_data_dir(const std::string &argv0, const std::string &appname);
 
 /// Changes the current working directory
 void chdir(const Path &);
diff --git a/source/path.cpp b/source/path.cpp
index c0b91d6..5424cb1 100644
--- a/source/path.cpp
+++ b/source/path.cpp
@@ -5,6 +5,7 @@ Copyright © 2006-2008  Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
 
+#include <msp/core/except.h>
 #include <msp/strings/utils.h>
 #include "path.h"
 #include "utils.h"
@@ -106,16 +107,15 @@ string Path::operator[](int n) const
 	}
 	else
 	{
-		for(Iterator i=--end();; --i)
+		for(Iterator i=end(); i!=begin();)
 		{
+			--i;
 			if(!++n)
 				return *i;
-			if(i==begin())
-				break;
 		}
 	}
 
-	return string();
+	throw InvalidParameterValue("Path component index out of range");
 }
 
 bool Path::operator==(const Path &p) const
@@ -180,7 +180,7 @@ void Path::add_component(const string &comp)
 #endif
 	else if(comp=="..")
 	{
-		if(path.empty())
+		if(path.empty() || path==".")
 			path=comp;
 		// .. in root directory is a no-op
 		else if(path.size()==1 && path[0]==DIRSEP)
@@ -199,15 +199,21 @@ void Path::add_component(const string &comp)
 				path+=DIRSEP;
 				path+=comp;
 			}
+			else if(slash==string::npos)
+				path=".";
 			else
+			{
+				if(slash==0)
+					slash=1;
 				// Otherwise, erase the last component
 				path.erase(slash, string::npos);
+			}
 		}
 	}
 	else if(comp!="." || path.empty())
 	{
-		if(path==".")
-			path="";
+		if(comp!="." && path.empty())
+			path=".";
 		if(path.size()>1 || (path.size()==1 && path[0]!=DIRSEP))
 			path+=DIRSEP;
 		path+=comp;
diff --git a/source/path.h b/source/path.h
index 8c24f19..751c0e3 100644
--- a/source/path.h
+++ b/source/path.h
@@ -23,6 +23,11 @@ enum
 #endif
 };
 
+/**
+Stores a filesystem path.  Paths are always stored in a normalized form; there
+are never any "." or ".." components in the middle of the path, and relative
+paths always begin with a single "." component or a sequence ".." components.
+*/
 class Path
 {
 public:
-- 
2.43.0