[c-host] initial agnostic option api and parser

common/CMakeLists.txt

@@ -5,10 +5,14 @@ include_directories(
 	${PROJECT_SOURCE_DIR}/include
 )
 
+set(SOURCES
+  src/option.c
+)
+
 if(WIN32)
-  add_library(lg_common STATIC src/crash.windows.c)
+  add_library(lg_common STATIC src/crash.windows.c ${SOURCES})
 else()
-  add_library(lg_common STATIC src/crash.linux.c)
+  add_library(lg_common STATIC src/crash.linux.c ${SOURCES})
   target_link_libraries(lg_common bfd)
 endif()
 

common/include/common/option.h

@@ -0,0 +1,75 @@
+/*
+KVMGFX Client - A KVM Client for VGA Passthrough
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <stdint.h>
+#include <stdbool.h>
+
+enum OptionType
+{
+  OPTION_TYPE_NONE = 0,
+  OPTION_TYPE_INT,
+  OPTION_TYPE_STRING,
+  OPTION_TYPE_BOOL
+};
+
+struct OptionState;
+
+struct OptionValue
+{
+  enum OptionType type;
+  union
+  {
+    int    x_int;
+    char * x_string;
+    bool   x_bool;
+  }
+  v;
+
+  // internal state
+  struct OptionState * state;
+};
+
+struct Option
+{
+  const char         * module;
+  const char         * name;
+  const char         * description;
+  struct OptionValue   value;
+
+  bool (*validator)(struct OptionValue * value);
+  void (*printHelp)();
+};
+
+// register an NULL terminated array of options
+bool option_register(struct Option options[]);
+
+// lookup the value of an option
+struct OptionValue * option_get       (const char * module, const char * name);
+int                  option_get_int   (const char * module, const char * name);
+const char *         option_get_string(const char * module, const char * name);
+bool                 option_get_bool  (const char * module, const char * name);
+
+// called by the main application to parse the command line arguments
+bool option_parse(int argc, char * argv[]);
+
+// print out the options, help, and their current values
+void option_print();
+
+// final cleanup
+void option_free();

common/src/option.c

@@ -0,0 +1,267 @@
+/*
+KVMGFX Client - A KVM Client for VGA Passthrough
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include "common/option.h"
+#include "common/debug.h"
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+struct OptionGroup
+{
+  const char    *  module;
+  struct Option ** options;
+  int              count;
+  int              pad;
+};
+
+struct State
+{
+  struct Option      * options;
+  int                  oCount;
+  struct OptionGroup * groups;
+  int                  gCount;
+};
+
+struct State state =
+{
+  .options = NULL,
+  .oCount  = 0,
+  .groups  = NULL,
+  .gCount  = 0
+};
+
+bool option_register(struct Option options[])
+{
+  int new = 0;
+  for(int i = 0; options[i].value.type != OPTION_TYPE_NONE; ++i)
+    ++new;
+
+  state.options = realloc(
+    state.options,
+    sizeof(struct Option) * (state.oCount + new)
+  );
+
+  for(int i = 0; options[i].value.type != OPTION_TYPE_NONE; ++i)
+  {
+    struct Option * o = &state.options[state.oCount + i];
+    memcpy(o, &options[i], sizeof(struct Option));
+
+    // ensure the string is locally allocated
+    if (o->value.type == OPTION_TYPE_STRING)
+      o->value.v.x_string = strdup(o->value.v.x_string);
+
+    // add the option to the correct group for help printout
+    bool found = false;
+    for(int g = 0; g < state.gCount; ++g)
+    {
+      struct OptionGroup * group = &state.groups[g];
+      if (strcmp(group->module, o->module) != 0)
+        continue;
+
+      found = true;
+      group->options = realloc(
+        group->options,
+        sizeof(struct Option *) * (group->count + 1)
+      );
+      group->options[group->count] = o;
+
+      int len = strlen(o->name);
+      if (len > group->pad)
+        group->pad = len;
+
+      ++group->count;
+    }
+
+    if (!found)
+    {
+      state.groups = realloc(
+        state.groups,
+        sizeof(struct OptionGroup) * (state.gCount + 1)
+      );
+
+      struct OptionGroup * group = &state.groups[state.gCount];
+      ++state.gCount;
+
+      group->module     = o->module;
+      group->options    = malloc(sizeof(struct Option *));
+      group->options[0] = o;
+      group->count      = 1;
+      group->pad        = strlen(o->name);
+    }
+  }
+
+  state.oCount += new;
+  return true;
+};
+
+void option_free()
+{
+  for(int i = 0; i < state.oCount; ++i)
+  {
+    struct Option * o = &state.options[i];
+    if (o->value.type == OPTION_TYPE_STRING)
+      free(o->value.v.x_string);
+  }
+  free(state.options);
+  state.options = NULL;
+  state.oCount  = 0;
+
+  free(state.groups);
+  state.groups  = NULL;
+  state.gCount  = 0;
+}
+
+bool option_parse(int argc, char * argv[])
+{
+  for(int a = 1; a < argc; ++a)
+  {
+    if (strcmp(argv[a], "-h") == 0 || strcmp(argv[a], "--help") == 0)
+    {
+      option_print();
+      return false;
+    }
+
+    char * arg    = strdup(argv[a]);
+    char * module = strtok(arg , ":");
+    char * name   = strtok(NULL, "=");
+    char * value  = strtok(NULL, "" );
+
+    if (!module || !name || !value)
+    {
+      DEBUG_WARN("Ignored invalid argument: %s", argv[a]);
+      free(arg);
+      continue;
+    }
+
+    bool found = false;
+    struct Option * o;
+    for(int i = 0; i < state.oCount; ++i)
+    {
+      o = &state.options[i];
+      if ((strcmp(o->module, module) != 0) || (strcmp(o->name, name) != 0))
+        continue;
+
+      found = true;
+      break;
+    }
+
+    if (!found)
+    {
+      DEBUG_WARN("Ignored unknown argument: %s", argv[a]);
+      free(arg);
+      continue;
+    }
+
+    switch(o->value.type)
+    {
+      case OPTION_TYPE_INT:
+        o->value.v.x_int = atol(value);
+        break;
+
+      case OPTION_TYPE_STRING:
+        free(o->value.v.x_string);
+        o->value.v.x_string = strdup(value);
+        break;
+
+      case OPTION_TYPE_BOOL:
+        o->value.v.x_bool =
+          strcmp(value, "1"   ) == 0 ||
+          strcmp(value, "yes" ) == 0 ||
+          strcmp(value, "true") == 0 ||
+          strcmp(value, "on"  ) == 0;
+        break;
+
+      default:
+        DEBUG_ERROR("BUG: Invalid option type, this should never happen");
+        assert(false);
+        break;
+    }
+
+    if (o->validator)
+      if (!o->validator(&o->value))
+      {
+        DEBUG_ERROR("Invalid value provided to option: %s", argv[a]);
+
+        if (o->printHelp)
+          o->printHelp();
+
+        return false;
+      }
+  }
+
+  return true;
+}
+
+void option_print()
+{
+  printf(
+    "The following is a complete list of options accepted by this application\n\n"
+  );
+
+  for(int g = 0; g < state.gCount; ++g)
+  {
+    for(int i = 0; i < state.groups[g].count; ++i)
+    {
+      struct Option * o = state.groups[g].options[i];
+      printf("  %s:%-*s - %s\n", o->module, state.groups[g].pad, o->name, o->description);
+    }
+    printf("\n");
+  }
+}
+
+struct OptionValue * option_get(const char * module, const char * name)
+{
+  for(int i = 0; i < state.oCount; ++i)
+  {
+    struct Option * o = &state.options[i];
+    if ((strcmp(o->module, module) == 0) || (strcmp(o->name, name) == 0))
+      return &o->value;
+  }
+  return NULL;
+}
+
+int option_get_int(const char * module, const char * name)
+{
+  struct OptionValue * o = option_get(module, name);
+  if (!o)
+    return -1;
+  assert(o->type == OPTION_TYPE_INT);
+  return o->v.x_int;
+}
+
+const char * option_get_string(const char * module, const char * name)
+{
+  struct OptionValue * o = option_get(module, name);
+  if (!o)
+    return NULL;
+  assert(o->type == OPTION_TYPE_STRING);
+  return o->v.x_string;
+}
+
+bool option_get_bool(const char * module, const char * name)
+{
+  struct OptionValue * o = option_get(module, name);
+  if (!o)
+    return false;
+  assert(o->type == OPTION_TYPE_BOOL);
+  return o->v.x_bool;
+}