From 50bdae2c0547051228361e439a72f8be62c3e936 Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Wed, 4 Oct 2017 15:19:47 +0300
Subject: Add ignore_error parameter for path_entry() and *_exists() functions

---
 libbutl/filesystem.cxx | 20 ++++++++++----------
 libbutl/filesystem.mxx | 41 ++++++++++++++++++++++++++---------------
 2 files changed, 36 insertions(+), 25 deletions(-)

diff --git a/libbutl/filesystem.cxx b/libbutl/filesystem.cxx
index 8c3abc4..da2f12c 100644
--- a/libbutl/filesystem.cxx
+++ b/libbutl/filesystem.cxx
@@ -75,34 +75,34 @@ using namespace std;
 namespace butl
 {
   bool
-  file_exists (const char* p, bool fl)
+  file_exists (const char* p, bool fl, bool ie)
   {
-    auto pe (path_entry (p, fl));
+    auto pe (path_entry (p, fl, ie));
     return pe.first && (pe.second.type == entry_type::regular ||
                         (!fl && pe.second.type == entry_type::symlink));
   }
 
   bool
-  entry_exists (const char* p, bool fl)
+  entry_exists (const char* p, bool fl, bool ie)
   {
-    return path_entry (p, fl).first;
+    return path_entry (p, fl, ie).first;
   }
 
   bool
-  dir_exists (const char* p)
+  dir_exists (const char* p, bool ie)
   {
-    auto pe (path_entry (p, true));
+    auto pe (path_entry (p, true, ie));
     return pe.first && pe.second.type == entry_type::directory;
   }
 
 #ifndef _WIN32
   pair<bool, entry_stat>
-  path_entry (const char* p, bool fl)
+  path_entry (const char* p, bool fl, bool ie)
   {
     struct stat s;
     if ((fl ? stat (p, &s) : lstat (p, &s)) != 0)
     {
-      if (errno == ENOENT || errno == ENOTDIR)
+      if (errno == ENOENT || errno == ENOTDIR || ie)
         return make_pair (false, entry_stat {entry_type::unknown, 0});
       else
         throw_generic_error (errno);
@@ -124,7 +124,7 @@ namespace butl
   }
 #else
   pair<bool, entry_stat>
-  path_entry (const char* p, bool)
+  path_entry (const char* p, bool, bool ie)
   {
     // A path like 'C:', while being a root path in our terminology, is not as
     // such for Windows, that maintains current directory for each drive, and
@@ -157,7 +157,7 @@ namespace butl
 
       if (_stat64 (p, &s) != 0)
       {
-        if (errno == ENOENT || errno == ENOTDIR)
+        if (errno == ENOENT || errno == ENOTDIR || ie)
           return make_pair (false, entry_stat {entry_type::unknown, 0});
         else
           throw_generic_error (errno);
diff --git a/libbutl/filesystem.mxx b/libbutl/filesystem.mxx
index b4caffe..bb78a4f 100644
--- a/libbutl/filesystem.mxx
+++ b/libbutl/filesystem.mxx
@@ -57,33 +57,41 @@ import butl.utility;
 LIBBUTL_MODEXPORT namespace butl
 {
   // Return true if the path is to an existing regular file. Note that by
-  // default this function follows symlinks.
+  // default this function follows symlinks. Underlying OS errors are reported
+  // by throwing std::system_error, unless ignore_error is true.
   //
   LIBBUTL_SYMEXPORT bool
-  file_exists (const char*, bool follow_symlinks = true);
+  file_exists (const char*,
+               bool follow_symlinks = true,
+               bool ignore_error = false);
 
   inline bool
-  file_exists (const path& p, bool fs = true) {
-    return file_exists (p.string ().c_str (), fs);}
+  file_exists (const path& p, bool fs = true, bool ie = false) {
+    return file_exists (p.string ().c_str (), fs, ie);}
 
   // Return true if the path is to an existing directory. Note that this
-  // function follows symlinks.
+  // function follows symlinks. Underlying OS errors are reported by throwing
+  // std::system_error, unless ignore_error is true.
   //
   LIBBUTL_SYMEXPORT bool
-  dir_exists (const char*);
+  dir_exists (const char*, bool ignore_error = false);
 
   inline bool
-  dir_exists (const path& p) {return dir_exists (p.string ().c_str ());}
+  dir_exists (const path& p, bool ie = false) {
+    return dir_exists (p.string ().c_str (), ie);}
 
   // Return true if the path is to an existing file system entry. Note that by
-  // default this function doesn't follow symlinks.
+  // default this function doesn't follow symlinks. Underlying OS errors are
+  // reported by throwing std::system_error, unless ignore_error is true.
   //
   LIBBUTL_SYMEXPORT bool
-  entry_exists (const char*, bool follow_symlinks = false);
+  entry_exists (const char*,
+                bool follow_symlinks = false,
+                bool ignore_error = false);
 
   inline bool
-  entry_exists (const path& p, bool fs = false) {
-    return entry_exists (p.string ().c_str (), fs);}
+  entry_exists (const path& p, bool fs = false, bool ie = false) {
+    return entry_exists (p.string ().c_str (), fs, ie);}
 
   // Filesystem entry type.
   //
@@ -106,14 +114,17 @@ LIBBUTL_MODEXPORT namespace butl
 
   // Return a flag indicating if the path is to an existing file system entry
   // and its type if so. Note that by default this function doesn't follow
-  // symlinks.
+  // symlinks. Underlying OS errors are reported by throwing std::system_error,
+  // unless ignore_error is true.
   //
   LIBBUTL_SYMEXPORT std::pair<bool, entry_stat>
-  path_entry (const char*, bool follow_symlinks = false);
+  path_entry (const char*,
+              bool follow_symlinks = false,
+              bool ignore_error = false);
 
   inline std::pair<bool, entry_stat>
-  path_entry (const path& p, bool fs = false) {
-    return path_entry (p.string ().c_str (), fs);}
+  path_entry (const path& p, bool fs = false, bool ie = false) {
+    return path_entry (p.string ().c_str (), fs, ie);}
 
   // Return true if the directory is empty. Note that the path must exist
   // and be a directory. This function follows symlinks.
-- 
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