Convert global.argv0 to a D slice

This is more of a proof of concept for future conversion.

Here's a few principles used to do the conversion from `T*` to `T[]`:
- If it's a string, the character at `s[$]` must be `'\0'`.
  It allows code to freely go back and forth between `char*` and `char[]`.
- Move the implementation to extern(D) and slices, and provide C++ wrapper.
- Stay on topic: those changes only focus on one parameter / module / function,
  because it's very easy to end up with a giant change that doesn't work.
- If `'\0'` termination is required (e.g. calling a C function),
  changing from `char*` to `char[]` should can be done using `toCStringThen`.

Author: Geod24

src/dmd/dinifile.d

@@ -24,6 +24,7 @@ import dmd.root.filename;
 import dmd.root.outbuffer;
 import dmd.root.port;
 import dmd.root.stringtable;
+import dmd.utils;
 
 version (Windows) extern (C) int putenv(const char*);
 private enum LOG = false;
@@ -37,11 +38,12 @@ private enum LOG = false;
  *      file path of the config file or NULL
  *      Note: this is a memory leak
  */
-const(char)* findConfFile(const(char)* argv0, const(char)* inifile)
+const(char)[] findConfFile(const(char)[] argv0, const(char)[] inifile)
 {
     static if (LOG)
     {
-        printf("findinifile(argv0 = '%s', inifile = '%s')\n", argv0, inifile);
+        printf("findinifile(argv0 = '%.*s', inifile = '%.*s')\n",
+               argv0.length, argv0.ptr, inifile.length, inifile.ptr);
     }
     if (FileName.absolute(inifile))
         return inifile;
@@ -54,16 +56,16 @@ const(char)* findConfFile(const(char)* argv0, const(char)* inifile)
      *      o directory off of argv0
      *      o SYSCONFDIR=/etc (non-windows)
      */
-    auto filename = FileName.combine(getenv("HOME"), inifile);
+    auto filename = FileName.combine(getenv("HOME").toDString, inifile);
     if (FileName.exists(filename))
         return filename;
     version (Windows)
     {
         // This fix by Tim Matthews
         char[MAX_PATH + 1] resolved_name;
-        if (GetModuleFileNameA(null, resolved_name.ptr, MAX_PATH + 1) && FileName.exists(resolved_name.ptr))
+        if (GetModuleFileNameA(null, resolved_name.ptr, MAX_PATH + 1) && FileName.exists(resolved_name))
         {
-            filename = FileName.replaceName(resolved_name.ptr, inifile);
+            filename = FileName.replaceName(resolved_name, inifile);
             if (FileName.exists(filename))
                 return filename;
         }
@@ -74,13 +76,13 @@ const(char)* findConfFile(const(char)* argv0, const(char)* inifile)
     version (Posix)
     {
         // Search PATH for argv0
-        auto p = getenv("PATH");
+        const p = getenv("PATH");
         static if (LOG)
         {
             printf("\tPATH='%s'\n", p);
         }
         auto paths = FileName.splitPath(p);
-        auto abspath = FileName.searchPath(paths, argv0, false);
+        auto abspath = FileName.searchPath(paths, argv0.ptr, false).toDString;
         if (abspath)
         {
             auto absname = FileName.replaceName(abspath, inifile);

src/dmd/frontend.d

@@ -79,7 +79,7 @@ string findDMDConfig(string dmdFilePath)
     import dmd.dinifile : findConfFile;
     import std.string : fromStringz, toStringz;
 
-    auto f = findConfFile(dmdFilePath.toStringz, "dmd.conf");
+    auto f = findConfFile(dmdFilePath.toStringz[0 .. dmdFilePath.length], "dmd.conf");
     if (f is null)
         return null;
 

src/dmd/globals.d

@@ -173,7 +173,7 @@ struct Param
 
     uint errorLimit = 20;
 
-    const(char)* argv0;                 // program name
+    const(char)[] argv0;                // program name
     Array!(const(char)*)* modFileAliasStrings; // array of char*'s of -I module filename alias strings
     Array!(const(char)*)* imppath;      // array of char*'s of where to look for import modules
     Array!(const(char)*)* fileImppath;  // array of char*'s of where to look for file import modules

src/dmd/globals.h

@@ -145,7 +145,7 @@ struct Param
 
     unsigned errorLimit;
 
-    const char *argv0;    // program name
+    DArray<const char>  argv0;    // program name
     Array<const char *> *modFileAliasStrings; // array of char*'s of -I module filename alias strings
     Array<const char *> *imppath;     // array of char*'s of where to look for import modules
     Array<const char *> *fileImppath; // array of char*'s of where to look for file import modules

src/dmd/json.d

@@ -922,7 +922,7 @@ public:
     {
         objectStart();
         requiredProperty("cwd", getcwd(null, 0).toDString);
-        requiredProperty("argv0", global.params.argv0.toDString);
+        requiredProperty("argv0", global.params.argv0);
         requiredProperty("config", global.inifilename.toDString);
         requiredProperty("libName", global.params.libname.toDString);
 

src/dmd/mars.d

@@ -218,7 +218,7 @@ private int tryMain(size_t argc, const(char)** argv)
     //for (size_t i = 0; i < arguments.dim; ++i) printf("arguments[%d] = '%s'\n", i, arguments[i]);
     files.reserve(arguments.dim - 1);
     // Set default values
-    global.params.argv0 = arguments[0];
+    global.params.argv0 = arguments[0].toDString;
 
     // Temporary: Use 32 bits as the default on Windows, for config parsing
     static if (TARGET.Windows)
@@ -235,11 +235,11 @@ private int tryMain(size_t argc, const(char)** argv)
     {
         version (Windows)
         {
-            global.inifilename = findConfFile(global.params.argv0, "sc.ini");
+            global.inifilename = findConfFile(global.params.argv0, "sc.ini").ptr;
         }
         else version (Posix)
         {
-            global.inifilename = findConfFile(global.params.argv0, "dmd.conf");
+            global.inifilename = findConfFile(global.params.argv0, "dmd.conf").ptr;
         }
         else
         {
@@ -1415,7 +1415,7 @@ private void printPredefinedVersions(FILE* stream)
 
 extern(C) void printGlobalConfigs(FILE* stream)
 {
-    stream.fprintf("binary    %s\n", global.params.argv0);
+    stream.fprintf("binary    %*s\n", global.params.argv0.length, global.params.argv0.ptr);
     stream.fprintf("version   %s\n", global._version);
     stream.fprintf("config    %s\n", global.inifilename ? global.inifilename : "(none)");
     // Print DFLAGS environment variable

src/dmd/root/filename.d

@@ -300,12 +300,6 @@ nothrow:
     /**************************************
      * Replace filename portion of path.
      */
-    extern (C++) static const(char)* replaceName(const(char)* path, const(char)* name)
-    {
-        return replaceName(path[0 .. strlen(path)], name[0 .. strlen(name)]).ptr;
-    }
-
-    /// Ditto
     extern (D) static const(char)[] replaceName(const(char)[] path, const(char)[] name)
     {
         if (absolute(name))