[beast: 4/19] BSE: bsetool: add simple argument parser

[Tim Janik <timj src gnome org>]

commit 06dab3dd43e9b51b07f8516707b5c09b6c24c272
Author: Tim Janik <timj gnu org>
Date:   Mon Sep 7 01:31:28 2015 +0200

    BSE: bsetool: add simple argument parser

 bse/Makefile.am |    2 +-
 bse/bsetool.cc  |  138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 137 insertions(+), 3 deletions(-)
---
diff --git a/bse/Makefile.am b/bse/Makefile.am
index 8460b59..065c21b 100644
--- a/bse/Makefile.am
+++ b/bse/Makefile.am
@@ -364,7 +364,7 @@ bseinfo_LDADD    = $(progs_LDADD)
 # == bsetool ==
 noinst_PROGRAMS += bsetool
 bsetool_SOURCES  = bsetool.cc
-bsetool_LDADD    = libbse.la
+bsetool_LDADD    = libbse.la $(RAPICORN_LIBS)
 
 # == Tests ==
 EXTRA_DIST += oldidl.idl
diff --git a/bse/bsetool.cc b/bse/bsetool.cc
index a57fcb1..157070e 100644
--- a/bse/bsetool.cc
+++ b/bse/bsetool.cc
@@ -1,15 +1,149 @@
 // Licensed GNU LGPL v2.1 or later: http://www.gnu.org/licenses/lgpl.html
 #include <bse/bsemain.hh>
+#include <bse/bseserver.hh>
 #include <sys/resource.h>
+#include <unordered_map>
 #include <unistd.h>
 #include <stdio.h>
 
+using namespace Bse;
+
+struct ArgDescription {
+  const char *arg_name, *value_name, *arg_blurb;
+  String value;
+};
+
+class ArgParser {
+  const size_t                                n_args_;
+  ArgDescription                             *const args_;
+  std::unordered_map<String, ArgDescription*> names_;
+  void     parse_args (const size_t N, const ArgDescription *adescs);
+public:
+  template<size_t N>
+  explicit ArgParser  (ArgDescription (&adescs) [N]) : n_args_ (N), args_ (adescs) {}
+  String   parse_args (const uint argc, char *const argv[]); // returns error message
+  String   operator[] (const String &arg_name) const;
+};
+
+String
+ArgParser::operator[] (const String &arg_name) const
+{
+  auto it = names_.find (arg_name);
+  if (it == names_.end())
+    return "";
+  ArgDescription *adesc = it->second;
+  return adesc->value;
+}
+
+String
+ArgParser::parse_args (const uint argc, char *const argv[])
+{
+  std::unordered_map<String, String> aliases;
+  std::vector<String> fixed; // fixed arguments, like <OBLIGATION> or [OPTIONAL]
+  size_t need_obligatory = 0;
+  // fill names_ from args_
+  for (size_t i = 0; i < n_args_; i++)
+    {
+      StringVector names = string_split (args_[i].arg_name, ",");
+      for (size_t j = 0; j < names.size(); j++)
+        {
+          String name = string_canonify (names[j], string_set_a2z() + string_set_A2Z() + "0123456789_-", "");
+          while (name[0] == '-')
+            name = name.substr (1);
+          if (name.empty())
+            continue;
+          if (j == 0)
+            {
+              names_[name] = &args_[i];
+              if (names[j][0] == '<')
+                {
+                  need_obligatory++;
+                  fixed.push_back (name);
+                }
+              else if (names[j][0] == '[')
+                fixed.push_back (name);
+            }
+          else // found an alias after ','
+            names_[name] = &args_[i];
+        }
+    }
+  // parse and assign command line arguments
+  bool seen_dashdash = false;
+  size_t fixed_index = 0;
+  for (size_t i = 0; i < argc; i++)
+    if (!argv[i])
+      continue;
+    else if (argv[i][0] == '-' && argv[i][1] == '-' && argv[i][2] == 0)
+      seen_dashdash = true;
+    else if (!seen_dashdash && argv[i][0] == '-')
+      {
+        const char *arg = argv[i] + 1 + (argv[i][1] == '-');
+        const char *eq = strchr (arg, '=');
+        String arg_name = !eq ? arg : String (arg, eq - arg);
+        auto it = names_.find (arg_name);
+        if (it == names_.end())
+          return string_format ("invalid argument: %s", argv[i]);
+        ArgDescription *adesc = it->second;
+        if (adesc->value_name && adesc->value_name[0])
+          {
+            if (eq)
+              adesc->value = eq + 1;
+            else
+              {
+                if (i + 1 >= argc)
+                  return string_format ("incomplete argument: %s", argv[i]); // argument lacks value 
assignment
+                i++;
+                adesc->value = argv[i];
+              }
+          }
+        else
+          adesc->value = "1"; // value means 'option is present'
+      }
+    else // non-option arguments
+      {
+        if (fixed_index >= fixed.size())
+          return string_format ("invalid extra argument: %s", argv[i]);
+        ArgDescription *adesc = names_[fixed[fixed_index]];
+        adesc->value = argv[i];
+        fixed_index++;
+      }
+  if (fixed_index < need_obligatory)
+    return string_format ("missing mandatory argument <%s>", fixed[fixed_index]);
+  return ""; // success
+}
+
+static ArgDescription bsetool_options[] = {
+  { "--bse-no-load", "", "Prevent automated plugin and script registration", "" },
+};
+
 int
 main (int argc, char *argv[])
 {
+  printout ("bsetool!\n");
   bse_init_inprocess (&argc, argv, "bsetool"); // Bse::cstrings_to_vector (NULL)
   // now that the BSE thread runs, drop scheduling priorities if we have any
   setpriority (PRIO_PROCESS, getpid(), 0);
-  printf ("bsetool!\n");
-  return 0;
+  // pre-command option argument parsing
+  size_t option_argc = 1; // skip argv[0]
+  while (option_argc < argc && argv[option_argc][0] == '-')
+    option_argc++;
+  ArgParser toolap (bsetool_options);
+  String error = toolap.parse_args (option_argc - 1, argv + 1); // skip argv[0]
+  if (!error.empty())
+    {
+      printerr ("%s: %s\n", argv[0], error);
+      return 127;
+    }
+  // load BSE plugins, scripts, ladspa plugins, etc
+  if (!string_to_bool (toolap["bse-no-load"]))
+    {
+      BSE_SERVER.register_core_plugins();
+      while (g_main_context_pending (bse_main_context))
+        {
+          printout (".");
+          g_main_context_iteration (bse_main_context, false);
+        }
+      printout ("\n");
+    }
+  return 0; // success
 }