Add b_info() overload that returns information for multiple projects

2 files changed, 113 insertions, 39 deletions

diff --git a/libbutl/b.cxx b/libbutl/b.cxx
index c55496c..86a87ff 100644
--- a/libbutl/b.cxx
+++ b/libbutl/b.cxx
@@ -72,8 +72,9 @@ namespace butl
     throw runtime_error ("invalid " + d);
   }
 
-  b_project_info
-  b_info (const dir_path& project,
+  void
+  b_info (std::vector<b_project_info>& r,
+          const vector<dir_path>& projects,
           bool ext_mods,
           uint16_t verb,
           const function<b_callback>& cmd_callback,
@@ -81,6 +82,20 @@ namespace butl
           const dir_path& search_fallback,
           const vector<string>& ops)
   {
+    // Bail out if the project list is empty.
+    //
+    if (projects.empty ())
+      return;
+
+    // Reserve enough space in the result and save its original size.
+    //
+    size_t rn (r.size ());
+    {
+      size_t n (rn + projects.size ());
+      if (r.capacity () < n)
+        r.reserve (n);
+    }
+
     try
     {
       process_path pp (
@@ -106,6 +121,14 @@ namespace butl
         else
           vops.push_back ("-q");
 
+        vector<string> ps;
+        ps.reserve (projects.size ());
+
+        // Note that quoting is essential here.
+        //
+        for (const dir_path& p: projects)
+          ps.push_back ("'" + p.representation () + "'");
+
         pr = process_start_callback (
           cmd_callback ? cmd_callback : [] (const char* const*, size_t) {},
           0 /* stdin */,
@@ -116,7 +139,7 @@ namespace butl
           ext_mods ? nullptr : "--no-external-modules",
           "-s",
           ops,
-          "info:", "'" + project.representation () + "'");
+          "info:", ps);
 
         pipe.out.close ();
         ifdstream is (move (pipe.in), fdstream_mode::skip, ifdstream::badbit);
@@ -146,22 +169,52 @@ namespace butl
           }
         };
 
-        b_project_info r;
+        b_project_info pi;
+        auto add_project = [&r, &pi] ()
+        {
+          // Parse version string to standard version if the project loaded
+          // the version module.
+          //
+          const auto& ms (pi.modules);
+          if (find (ms.begin (), ms.end (), "version") != ms.end ())
+          {
+            try
+            {
+              pi.version = standard_version (pi.version_string,
+                                             standard_version::allow_stub);
+            }
+            catch (const invalid_argument& e)
+            {
+              bad_value ("version '" + pi.version_string + "': " + e.what ());
+            }
+          }
+
+          // Add the project info and prepare for the next project info
+          // parsing.
+          //
+          r.push_back (move (pi));
+          pi = b_project_info ();
+        };
+
         for (string l; !eof (getline (is, l)); )
         {
-          if (l.compare (0, 9, "project: ") == 0)
+          if (l.empty ())
+          {
+            add_project ();
+          }
+          else if (l.compare (0, 9, "project: ") == 0)
           {
             string v (l, 9);
             if (!v.empty ())
-              r.project = parse_name (move (v), "project");
+              pi.project = parse_name (move (v), "project");
           }
           else if (l.compare (0, 9, "version: ") == 0)
           {
-            r.version_string = string (l, 9);
+            pi.version_string = string (l, 9);
           }
           else if (l.compare (0, 9, "summary: ") == 0)
           {
-            r.summary = string (l, 9);
+            pi.summary = string (l, 9);
           }
           else if (l.compare (0, 5, "url: ") == 0)
           {
@@ -169,7 +222,7 @@ namespace butl
             if (!v.empty ())
             try
             {
-              r.url = url (v);
+              pi.url = url (v);
             }
             catch (const invalid_argument& e)
             {
@@ -178,17 +231,17 @@ namespace butl
           }
           else if (l.compare (0, 10, "src_root: ") == 0)
           {
-            r.src_root = parse_dir (string (l, 10), "src_root");
+            pi.src_root = parse_dir (string (l, 10), "src_root");
           }
           else if (l.compare (0, 10, "out_root: ") == 0)
           {
-            r.out_root = parse_dir (string (l, 10), "out_root");
+            pi.out_root = parse_dir (string (l, 10), "out_root");
           }
           else if (l.compare (0, 14, "amalgamation: ") == 0)
           {
             string v (l, 14);
             if (!v.empty ())
-              r.amalgamation = parse_dir (move (v), "amalgamation");
+              pi.amalgamation = parse_dir (move (v), "amalgamation");
           }
           else if (l.compare (0, 13, "subprojects: ") == 0)
           {
@@ -206,7 +259,7 @@ namespace butl
               if (p != 0)
                 sn = parse_name (string (s, 0, p), "subproject");
 
-              r.subprojects.push_back (
+              pi.subprojects.push_back (
                 b_project_info::subproject {move (sn),
                                             parse_dir (string (s, p + 1),
                                                        "subproject")});
@@ -216,19 +269,19 @@ namespace butl
           {
             string v (l, 12);
             for (size_t b (0), e (0); next_word (v, b, e); )
-              r.operations.push_back (string (v, b, e - b));
+              pi.operations.push_back (string (v, b, e - b));
           }
           else if (l.compare (0, 17, "meta-operations: ") == 0)
           {
             string v (l, 17);
             for (size_t b (0), e (0); next_word (v, b, e); )
-              r.meta_operations.push_back (string (v, b, e - b));
+              pi.meta_operations.push_back (string (v, b, e - b));
           }
           else if (l.compare (0, 9, "modules: ") == 0)
           {
             string v (l, 9);
             for (size_t b (0), e (0); next_word (v, b, e); )
-              r.modules.push_back (string (v, b, e - b));
+              pi.modules.push_back (string (v, b, e - b));
           }
         }
 
@@ -236,24 +289,15 @@ namespace butl
 
         if (pr.wait ())
         {
-          // Parse version string to standard version if the project loaded
-          // the version module.
-          //
-          const auto& ms (r.modules);
-          if (find (ms.begin (), ms.end (), "version") != ms.end ())
-          {
-            try
-            {
-              r.version = standard_version (r.version_string,
-                                            standard_version::allow_stub);
-            }
-            catch (const invalid_argument& e)
-            {
-              bad_value ("version '" + r.version_string + "': " + e.what ());
-            }
-          }
+          add_project (); // Add the remaining project info.
+
+          if (r.size () - rn == projects.size ())
+            return;
 
-          return r;
+          ostringstream os;
+          os << "invalid " << pp << " output: expected information for "
+             << projects.size () << " projects instead of " << r.size () - rn;
+          throw b_error (os.str (), move (pr.exit));
         }
       }
       // Note that ios::failure inherits from std::runtime_error, so this
diff --git a/libbutl/b.mxx b/libbutl/b.mxx
index 97dcf0c..cca9696 100644
--- a/libbutl/b.mxx
+++ b/libbutl/b.mxx
@@ -10,6 +10,7 @@
 #ifndef __cpp_lib_modules_ts
 #include <string>
 #include <vector>
+#include <utility>    // move()
 #include <cstddef>    // size_tu
 #include <cstdint>    // uint16_t
 #include <stdexcept>  // runtime_error
@@ -64,8 +65,12 @@ LIBBUTL_MODEXPORT namespace butl
     b_error (const std::string& description, optional<process_exit> = nullopt);
   };
 
-  // Run `b info: <project-dir>` command and parse and return the build2
-  // project information it prints to stdout. Throw b_error on error.
+  // Run `b info: <project-dir>...` command and parse and return (via argument
+  // to allow appending and for error position; see below) the build2 projects
+  // information it prints to stdout. Return the empty list if the specified
+  // project list is empty. Throw b_error on error. Note that the size of the
+  // result vector can be used to determine which project information caused
+  // the error.
   //
   // Unless you need information that may come from external modules
   // (operations, meta-operations, etc), pass false as the ext_mods argument,
@@ -76,8 +81,8 @@ LIBBUTL_MODEXPORT namespace butl
   // (see process_run_callback() for details), build program search details,
   // and additional options.
   //
-  // Note that version_string is only parsed to standard_version if the
-  // project uses the version module. Otherwise, standard_version is empty.
+  // Note that version_string is only parsed to standard_version if a project
+  // uses the version module. Otherwise, standard_version is empty.
   //
   struct b_project_info
   {
@@ -110,12 +115,37 @@ LIBBUTL_MODEXPORT namespace butl
 
   using b_callback = void (const char* const args[], std::size_t n);
 
-  LIBBUTL_SYMEXPORT b_project_info
-  b_info (const dir_path& project,
+  LIBBUTL_SYMEXPORT void
+  b_info (std::vector<b_project_info>& result,
+          const std::vector<dir_path>& projects,
           bool ext_mods,
           std::uint16_t verb = 1,
           const std::function<b_callback>& cmd_callback = {},
           const path& program = path ("b"),
           const dir_path& search_fallback = {},
           const std::vector<std::string>& options = {});
+
+  // As above but retrieve information for a single project.
+  //
+  inline b_project_info
+  b_info (const dir_path& project,
+          bool ext_mods,
+          std::uint16_t verb = 1,
+          const std::function<b_callback>& cmd_callback = {},
+          const path& program = path ("b"),
+          const dir_path& search_fallback = {},
+          const std::vector<std::string>& options = {})
+  {
+    std::vector<b_project_info> r;
+    b_info (r,
+            std::vector<dir_path> ({project}),
+            ext_mods,
+            verb,
+            cmd_callback,
+            program,
+            search_fallback,
+            options);
+
+    return std::move (r[0]);
+  }
 }