From d82deea833d1adf993b115049ee60b628c530420 Mon Sep 17 00:00:00 2001
From: Daniel Kolesa <d.kolesa@samsung.com>
Date: Thu, 11 Oct 2018 16:36:50 +0200
Subject: [PATCH] eolian gen: add generation of build dependencies

It is now possible to generate a separate .d file which will
contain Make-style dependencies for the files generated in that
batch, i.e. if you geerate header, legacy header and source, the
.eo.d file will contain dependency lists for those three.

It should be possible to integrate this into our build system to
enable proper regeneration of .eo files in an incremental manner.

Fixes T2251.
---
 src/bin/eolian/main.c | 74 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 4 deletions(-)

diff --git a/src/bin/eolian/main.c b/src/bin/eolian/main.c
index db8ea371dd..95d81a7e04 100644
--- a/src/bin/eolian/main.c
+++ b/src/bin/eolian/main.c
@@ -14,12 +14,13 @@ enum
    GEN_H_LEGACY = 1 << 1,
    GEN_H_STUB   = 1 << 2,
    GEN_C        = 1 << 3,
-   GEN_C_IMPL   = 1 << 4
+   GEN_C_IMPL   = 1 << 4,
+   GEN_D        = 1 << 5
 };
 
-static const char *_dexts[5] =
+static const char *_dexts[6] =
 {
-  ".h", ".legacy.h", ".stub.h", ".c", ".c"
+  ".h", ".legacy.h", ".stub.h", ".c", ".c", ".d"
 };
 
 static int
@@ -50,6 +51,7 @@ _print_usage(const char *progn, FILE *outf)
                  "  s: Stub C header file (.eo.stub.h/.eot.stub.h)\n"
                  "  c: C source file (.eo.c)\n"
                  "  i: Implementation file (.c, merged with existing)\n"
+                 "  d: Make-style dependencies (.d)\n"
                  "\n"
                  "By default, the 'hc' set is used ('h' for .eot files).\n\n"
                  "The system-wide Eolian directory is scanned for eo files\n"
@@ -98,6 +100,9 @@ _try_set_out(char t, char **outs, const char *val, int *what)
         pos = _get_bit_pos(GEN_C_IMPL);
         *what |= GEN_C_IMPL;
         break;
+      case 'd':
+        pos = _get_bit_pos(GEN_D);
+        *what |= GEN_D;
      }
    if (pos < 0)
      return EINA_FALSE;
@@ -420,12 +425,68 @@ _write_impl(const Eolian_State *eos, const char *ofname, const char *ifname)
    return ret;
 }
 
+static void
+_append_dep_line(Eina_Strbuf *buf, Eina_Strbuf *dbuf, char **outs, int gen_what, int what)
+{
+   if (!(gen_what & what))
+     return;
+   eina_strbuf_append(buf, outs[_get_bit_pos(what)]);
+   eina_strbuf_append_buffer(buf, dbuf);
+}
+
+static Eina_Bool
+_write_deps(const Eolian_State *eos, const char *ofname, const char *ifname,
+            char **outs, int gen_what)
+{
+   INF("generating deps: %s", ofname);
+
+   Eina_Bool ret = EINA_TRUE;
+   Eina_Strbuf *buf = eina_strbuf_new();
+   Eina_Strbuf *dbuf = eina_strbuf_new();
+
+   const Eolian_Unit *un = eolian_state_unit_by_file_get(eos, ifname);
+   if (!un)
+     {
+        ret = EINA_FALSE;
+        goto result;
+     }
+
+   eina_strbuf_append(dbuf, ": ");
+   /* every generated file depends on its .eo/.eot file */
+   eina_strbuf_append(dbuf, eolian_unit_file_path_get(un));
+
+   const Eolian_Unit *dun;
+   Eina_Iterator *deps = eolian_unit_children_get(un);
+   EINA_ITERATOR_FOREACH(deps, dun)
+     {
+        const char *dpath = eolian_unit_file_path_get(dun);
+        if (!dpath)
+          continue;
+        eina_strbuf_append_char(dbuf, ' ');
+        eina_strbuf_append(dbuf, dpath);
+     }
+   eina_iterator_free(deps);
+   eina_strbuf_append_char(dbuf, '\n');
+
+   _append_dep_line(buf, dbuf, outs, gen_what, GEN_H);
+   _append_dep_line(buf, dbuf, outs, gen_what, GEN_H_LEGACY);
+   _append_dep_line(buf, dbuf, outs, gen_what, GEN_H_STUB);
+   _append_dep_line(buf, dbuf, outs, gen_what, GEN_C);
+   _append_dep_line(buf, dbuf, outs, gen_what, GEN_C_IMPL);
+
+   ret = _write_file(ofname, buf);
+result:
+   eina_strbuf_free(dbuf);
+   eina_strbuf_free(buf);
+   return ret;
+}
+
 int
 main(int argc, char **argv)
 {
    int pret = 1;
 
-   char *outs[5] = { NULL, NULL, NULL, NULL, NULL };
+   char *outs[6] = { NULL, NULL, NULL, NULL, NULL, NULL };
    char *basen = NULL;
    Eina_List *includes = NULL;
 
@@ -478,6 +539,9 @@ main(int argc, char **argv)
                case 'i':
                  gen_what |= GEN_C_IMPL;
                  break;
+               case 'd':
+                 gen_what |= GEN_D;
+                 break;
                default:
                  fprintf(stderr, "unknown type: '%c'\n", *wstr);
                  goto end;
@@ -575,6 +639,8 @@ main(int argc, char **argv)
      succ = _write_source(eos, outs[_get_bit_pos(GEN_C)], eobn, !strcmp(ext, ".eot"));
    if (succ && (gen_what & GEN_C_IMPL))
      succ = _write_impl(eos, outs[_get_bit_pos(GEN_C_IMPL)], eobn);
+   if (succ && (gen_what & GEN_D))
+     succ = _write_deps(eos, outs[_get_bit_pos(GEN_D)], eobn, outs, gen_what);
 
    if (!succ)
      goto end;