Add ability to specify custom path list in process::path_search()

3 files changed, 56 insertions, 28 deletions

diff --git a/libbutl/process.cxx b/libbutl/process.cxx
index b82af3c..bc05c5c 100644
--- a/libbutl/process.cxx
+++ b/libbutl/process.cxx
@@ -183,12 +183,13 @@ namespace butl
   // process
   //
   static process_path
-  path_search (const char*, const dir_path&, bool);
+  path_search (const char*, const dir_path&, bool, const char*);
 
   process_path process::
-  path_search (const char* f, bool init, const dir_path& fb, bool po)
+  path_search (const char* f, bool init,
+               const dir_path& fb, bool po, const char* ps)
   {
-    process_path r (try_path_search (f, init, fb, po));
+    process_path r (try_path_search (f, init, fb, po, ps));
 
     if (r.empty ())
       throw process_error (ENOENT);
@@ -197,9 +198,10 @@ namespace butl
   }
 
   process_path process::
-  try_path_search (const char* f, bool init, const dir_path& fb, bool po)
+  try_path_search (const char* f, bool init,
+                   const dir_path& fb, bool po, const char* ps)
   {
-    process_path r (butl::path_search (f, fb, po));
+    process_path r (butl::path_search (f, fb, po, ps));
 
     if (!init && !r.empty ())
     {
@@ -250,7 +252,7 @@ namespace butl
 #ifndef _WIN32
 
   static process_path
-  path_search (const char* f, const dir_path& fb, bool)
+  path_search (const char* f, const dir_path& fb, bool, const char* paths)
   {
     // Note that there is a similar version for Win32.
 
@@ -326,8 +328,11 @@ namespace butl
     // 2. We do not continue searching on EACCES from exec().
     // 3. We do not execute via default shell on ENOEXEC from exec().
     //
-    optional<string> p (getenv ("PATH"));
-    for (const char* b (p ? p->c_str () : nullptr), *e;
+    optional<string> paths_env;
+    if (paths == nullptr && (paths_env = getenv ("PATH")))
+      paths = paths_env->c_str ();
+
+    for (const char* b (paths), *e;
          b != nullptr;
          b = (e != nullptr ? e + 1 : e))
     {
@@ -930,7 +935,7 @@ namespace butl
 #else // _WIN32
 
   static process_path
-  path_search (const char* f, const dir_path& fb, bool po)
+  path_search (const char* f, const dir_path& fb, bool po, const char* paths)
   {
     // Note that there is a similar version for Win32.
 
@@ -1104,8 +1109,11 @@ namespace butl
 
     // Now search in PATH. Recall is unchanged.
     //
-    optional<string> p (getenv ("PATH"));
-    for (const char* b (p ? p->c_str () : nullptr), *e;
+    optional<string> paths_env;
+    if (paths == nullptr && (paths_env = getenv ("PATH")))
+      paths = paths_env->c_str ();
+
+    for (const char* b (paths), *e;
          b != nullptr;
          b = (e != nullptr ? e + 1 : e))
     {
diff --git a/libbutl/process.ixx b/libbutl/process.ixx
index accc57b..c7459c8 100644
--- a/libbutl/process.ixx
+++ b/libbutl/process.ixx
@@ -106,9 +106,9 @@ namespace butl
 #endif
 
   inline process_path process::
-  path_search (const char*& a0, const dir_path& fb, bool po)
+  path_search (const char*& a0, const dir_path& fb, bool po, const char* ps)
   {
-    process_path r (path_search (a0, true, fb, po));
+    process_path r (path_search (a0, true, fb, po, ps));
 
     if (!r.recall.empty ())
     {
@@ -120,27 +120,31 @@ namespace butl
   }
 
   inline process_path process::
-  path_search (const std::string& f, bool i, const dir_path& fb, bool po)
+  path_search (const std::string& f, bool i,
+               const dir_path& fb, bool po, const char* ps)
   {
-    return path_search (f.c_str (), i, fb, po);
+    return path_search (f.c_str (), i, fb, po, ps);
   }
 
   inline process_path process::
-  path_search (const path& f, bool i, const dir_path& fb, bool po)
+  path_search (const path& f, bool i,
+               const dir_path& fb, bool po, const char* ps)
   {
-    return path_search (f.string ().c_str (), i, fb, po);
+    return path_search (f.string ().c_str (), i, fb, po, ps);
   }
 
   inline process_path process::
-  try_path_search (const std::string& f, bool i, const dir_path& fb, bool po)
+  try_path_search (const std::string& f, bool i,
+                   const dir_path& fb, bool po, const char* ps)
   {
-    return try_path_search (f.c_str (), i, fb, po);
+    return try_path_search (f.c_str (), i, fb, po, ps);
   }
 
   inline process_path process::
-  try_path_search (const path& f, bool i, const dir_path& fb, bool po)
+  try_path_search (const path& f, bool i,
+                   const dir_path& fb, bool po, const char* ps)
   {
-    return try_path_search (f.string ().c_str (), i, fb, po);
+    return try_path_search (f.string ().c_str (), i, fb, po, ps);
   }
 
   inline process::
diff --git a/libbutl/process.mxx b/libbutl/process.mxx
index 13438be..7a331da 100644
--- a/libbutl/process.mxx
+++ b/libbutl/process.mxx
@@ -405,10 +405,14 @@ LIBBUTL_MODEXPORT namespace butl
     // (or in CWD if there is a directory component) ignoring other places
     // (like calling process' directory and, gasp, CWD on Windows).
     //
+    // If the paths argument is not NULL, search in this list of paths rather
+    // than in the PATH environment variable.
+    //
     static process_path
     path_search (const char*& args0,
                  const dir_path& fallback = dir_path (),
-                 bool path_only = false);
+                 bool path_only = false,
+                 const char* paths = nullptr);
 
     // This version is primarily useful when you want to pre-search the
     // executable before creating the args[] array. In this case you will
@@ -425,30 +429,42 @@ LIBBUTL_MODEXPORT namespace butl
     //
     static process_path
     path_search (const char* file, bool init,
-                 const dir_path& = dir_path (), bool = false);
+                 const dir_path& = dir_path (),
+                 bool = false,
+                 const char* = nullptr);
 
     static process_path
     path_search (const std::string&, bool,
-                 const dir_path& = dir_path (), bool = false);
+                 const dir_path& = dir_path (),
+                 bool = false,
+                 const char* = nullptr);
 
     static process_path
     path_search (const path&, bool,
-                 const dir_path& = dir_path (), bool = false);
+                 const dir_path& = dir_path (),
+                 bool = false,
+                 const char* = nullptr);
 
     // As above but if not found return empty process_path instead of
     // throwing.
     //
     static process_path
     try_path_search (const char*, bool,
-                     const dir_path& = dir_path (), bool = false);
+                     const dir_path& = dir_path (),
+                     bool = false,
+                     const char* = nullptr);
 
     static process_path
     try_path_search (const std::string&, bool,
-                     const dir_path& = dir_path (), bool = false);
+                     const dir_path& = dir_path (),
+                     bool = false,
+                     const char* = nullptr);
 
     static process_path
     try_path_search (const path&, bool,
-                     const dir_path& = dir_path (), bool = false);
+                     const dir_path& = dir_path (),
+                     bool = false,
+                     const char* = nullptr);
 
     // Print process commmand line. If the number of elements is specified,
     // then it will print the piped multi-process command line, if present.