From 08688bfc12a42a0399bcbdd6fe7d30d8f2486775 Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Wed, 13 Dec 2017 04:07:04 +0300
Subject: Add workaround for libpkgconf flags parsing issue

---
 build2/cc/pkgconfig.cxx | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'build2/cc/pkgconfig.cxx')

diff --git a/build2/cc/pkgconfig.cxx b/build2/cc/pkgconfig.cxx
index 1ad9f77..6eab22c 100644
--- a/build2/cc/pkgconfig.cxx
+++ b/build2/cc/pkgconfig.cxx
@@ -241,6 +241,54 @@ namespace build2
     return r;
   }
 
+  // Unescape backslashes in fragment data.
+  //
+  // Note that currently libpkgconf parses flags:
+  //
+  // "-IC:\\D C"
+  // '-IC:\D C'
+  // -IC:\\D\ C
+  //
+  // into fragments data:
+  //
+  // C:\D C
+  // C:D C
+  // C:\\D C
+  //
+  // This looks broken, as we could expect all 3 forms to result in the same
+  // (most natural) internal representation:
+  //
+  // C:\D C
+  //
+  // We workaround this issue for the third case, unescaping backslashes. This
+  // way we can break the first case, but that's not very probable. And we
+  // can't do much about the second case.
+  //
+  static void
+  unescape (pkgconf_list_t& frags)
+  {
+    pkgconf_node_t *node;
+    PKGCONF_FOREACH_LIST_ENTRY(frags.head, node)
+    {
+      auto frag (static_cast<pkgconf_fragment_t*> (node->data));
+
+      char* d (frag->data);
+      for (char* s (d); *s != '\0'; ++s, ++d)
+      {
+        char c (*s);
+
+        // Unescape the backslash.
+        //
+        if (c == '\\' && s[1] == '\\')
+          ++s;
+
+        *d = c;
+      }
+
+      *d = '\0';
+    }
+  }
+
   // Note that some libpkgconf functions can potentially return NULL, failing
   // to allocate the required memory block. However, we will not check the
   // returned value for NULL as the library doesn't do so, prior to filling the
@@ -357,6 +405,7 @@ namespace build2
       throw failed (); // Assume the diagnostics is issued.
 
     unique_ptr<pkgconf_list_t, fragments_deleter> fd (&f); // Auto-deleter.
+    unescape (f);
     return to_strings (f, 'I', client_->filter_includedirs);
   }
 
@@ -386,6 +435,7 @@ namespace build2
       throw failed (); // Assume the diagnostics is issued.
 
     unique_ptr<pkgconf_list_t, fragments_deleter> fd (&f); // Auto-deleter.
+    unescape (f);
     return to_strings (f, 'L', client_->filter_libdirs);
   }
 
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