From 291c9fa5bc475bbee096d4dd1a07931de922c7fa Mon Sep 17 00:00:00 2001
From: Denis Feklushkin <feklushkin.denis@gmail.com>
Date: Wed, 31 Jul 2024 18:38:47 +0300
Subject: [PATCH] ldc2.conf: %%ldcconfigpath%% placeholder added

---
 CHANGELOG.md        |  1 +
 driver/configfile.d | 40 ++++++++++++++++++++++++++++++++++++----
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 22cf17ed9f1..c8439f1f62d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 #### Big news
 - Android: NDK for prebuilt package bumped from r26d to r27. (#4711)
+- ldc2.conf: %%ldcconfigpath%% placeholder added - specifies the directory where current configuration file is located. (#4717)
 
 #### Platform support
 
diff --git a/driver/configfile.d b/driver/configfile.d
index ed0eb9f4e37..e080016441a 100644
--- a/driver/configfile.d
+++ b/driver/configfile.d
@@ -96,6 +96,39 @@ unittest
     assert(replace(test4, pattern, "word") == "a word, yet other words");
 }
 
+const(char)* baseDir(const(char)* path)
+{
+    import dmd.root.filename: isDirSeparator;
+
+    foreach_reverse (i; 0 .. strlen(path))
+    {
+        if (path[i-1].isDirSeparator)
+        {
+            auto res = path[0 .. i].dup;
+            res[$-1] = '\0';
+
+            return &res[0];
+        }
+    }
+
+    assert (false);
+}
+
+struct CfgPaths
+{
+    const(char)* cfPath; /// ldc2.conf path
+    const(char)* binDir; /// ldc2.exe binary dir
+}
+
+string replacePlaceholders(string str, CfgPaths cfgPaths)
+{
+    immutable dBinDir = prepareBinDir(cfgPaths.binDir);
+    immutable dCfgDir = prepareBinDir(cfgPaths.cfPath.baseDir);
+
+    return str
+        .replace("%%ldcbinarypath%%", dBinDir)
+        .replace("%%ldcconfigpath%%", dCfgDir);
+}
 
 extern(C++) struct ConfigFile
 {
@@ -117,8 +150,7 @@ private:
     {
         switches.setDim(0);
         postSwitches.setDim(0);
-
-        immutable dBinDir = prepareBinDir(binDir);
+        const CfgPaths cfgPaths = { cfPath: cfPath, binDir: binDir };
 
         try
         {
@@ -156,7 +188,7 @@ private:
                 output.reserve(input.vals.length);
                 foreach (sw; input.vals)
                 {
-                    const finalSwitch = sw.replace("%%ldcbinarypath%%", dBinDir) ~ '\0';
+                    const finalSwitch = sw.replacePlaceholders(cfgPaths) ~ '\0';
                     output.push(finalSwitch.ptr);
                 }
             }
@@ -168,7 +200,7 @@ private:
             applyArray(_libDirs, libDirs);
 
             if (auto rpath = findScalarSetting(sections, "rpath"))
-                this.rpathcstr = (rpath.val.replace("%%ldcbinarypath%%", dBinDir) ~ '\0').ptr;
+                this.rpathcstr = (rpath.val.replacePlaceholders(cfgPaths) ~ '\0').ptr;
 
             return true;
         }