From c35a377fdcead2451f01b4229b21f66a45daf7fc Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Fri, 3 Apr 2020 13:44:26 -0400
Subject: [PATCH] SystemTools: Refactor CollapseFullPath to call getcwd only
when needed
Many calls to the one-argument `CollapseFullPath` variant already have
an absolute path and just need to collapse it. Avoid calling `getcwd`
if the result is not needed because it can be an expensive syscall.
---
SystemTools.cxx | 59 ++++++++++++++++++++++++++--------------------
SystemTools.hxx.in | 8 +++----
2 files changed, 38 insertions(+), 29 deletions(-)
diff --git a/SystemTools.cxx b/SystemTools.cxx
index ca0679e5..957ce159 100644
--- a/SystemTools.cxx
+++ b/SystemTools.cxx
@@ -3215,11 +3215,6 @@ bool SystemTools::FindProgramPath(const char* argv0, std::string& pathOut,
return true;
}
-std::string SystemTools::CollapseFullPath(const std::string& in_relative)
-{
- return SystemTools::CollapseFullPath(in_relative, nullptr);
-}
-
#if KWSYS_SYSTEMTOOLS_USE_TRANSLATION_MAP
void SystemTools::AddTranslationPath(const std::string& a,
const std::string& b)
@@ -3309,25 +3304,10 @@ static void SystemToolsAppendComponents(
}
}
-std::string SystemTools::CollapseFullPath(const std::string& in_path,
- const char* in_base)
-{
- // Use the current working directory as a base path.
- char buf[2048];
- const char* res_in_base = in_base;
- if (!res_in_base) {
- if (const char* cwd = Getcwd(buf, 2048)) {
- res_in_base = cwd;
- } else {
- res_in_base = "";
- }
- }
-
- return SystemTools::CollapseFullPath(in_path, std::string(res_in_base));
-}
+namespace {
-std::string SystemTools::CollapseFullPath(const std::string& in_path,
- const std::string& in_base)
+std::string CollapseFullPathImpl(std::string const& in_path,
+ std::string const* in_base)
{
// Collect the output path components.
std::vector<std::string> out_components;
@@ -3340,8 +3320,15 @@ std::string SystemTools::CollapseFullPath(const std::string& in_path,
// If the input path is relative, start with a base path.
if (path_components[0].empty()) {
std::vector<std::string> base_components;
- // Use the given base path.
- SystemTools::SplitPath(in_base, base_components);
+
+ if (in_base) {
+ // Use the given base path.
+ SystemTools::SplitPath(*in_base, base_components);
+ } else {
+ // Use the current working directory as a base path.
+ std::string cwd = SystemTools::GetCurrentWorkingDirectory();
+ SystemTools::SplitPath(cwd, base_components);
+ }
// Append base path components to the output path.
out_components.push_back(base_components[0]);
@@ -3380,6 +3367,28 @@ std::string SystemTools::CollapseFullPath(const std::string& in_path,
// Return the reconstructed path.
return newPath;
}
+}
+
+std::string SystemTools::CollapseFullPath(std::string const& in_path)
+{
+ return CollapseFullPathImpl(in_path, nullptr);
+}
+
+std::string SystemTools::CollapseFullPath(std::string const& in_path,
+ const char* in_base)
+{
+ if (!in_base) {
+ return CollapseFullPathImpl(in_path, nullptr);
+ }
+ std::string tmp_base = in_base;
+ return CollapseFullPathImpl(in_path, &tmp_base);
+}
+
+std::string SystemTools::CollapseFullPath(std::string const& in_path,
+ std::string const& in_base)
+{
+ return CollapseFullPathImpl(in_path, &in_base);
+}
// compute the relative path from here to there
std::string SystemTools::RelativePath(const std::string& local,
diff --git a/SystemTools.hxx.in b/SystemTools.hxx.in
index b2a97f16..e13d03e2 100644
--- a/SystemTools.hxx.in
+++ b/SystemTools.hxx.in
@@ -411,11 +411,11 @@ public:
* (which defaults to the current working directory). The full path
* is returned.
*/
- static std::string CollapseFullPath(const std::string& in_relative);
- static std::string CollapseFullPath(const std::string& in_relative,
+ static std::string CollapseFullPath(std::string const& in_path);
+ static std::string CollapseFullPath(std::string const& in_path,
const char* in_base);
- static std::string CollapseFullPath(const std::string& in_relative,
- const std::string& in_base);
+ static std::string CollapseFullPath(std::string const& in_path,
+ std::string const& in_base);
/**
* Get the real path for a given path, removing all symlinks. In
--
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