libdpkg: Merge nicknames table into fieldinfos

The current code first does a lookup to see if the fieldname is in the
nicknames table, if found fixes up the fieldname to the new alias, and
then always does a lookup for the normalized name in fieldinfos table.

This penalizes the common case (i.e. non-obsolete fieldnames)
substantially. Also moving the nicknames into the fieldinfos table will
allow to print correct fieldnames on error as those are not mangled any
more, and to provide new wrapper parse functions that print warnings for
the obsolete fieldnames.

3 files changed, 9 insertions, 30 deletions

diff --git a/debian/changelog b/debian/changelog
index 670266e9a..a33d3c7b2 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -29,6 +29,8 @@ dpkg (1.19.5) UNRELEASED; urgency=medium
   * libdpkg: Optimize error handling. Move the error reporting outside the
     involved functions so that we do not need to call gettext if there is no
     error, which has a significant performance cost.
+  * libdpkg: Merge nicknames table into fieldinfos, to stop penalizing the
+    lookup of non-obsolete fieldnames.
   * Perl modules:
     - Dpkg::Vendor::Debian: Add support for merged-usr-via-symlinks tainted
       tag. Suggested by Alexander E. Patrakov <patrakov@gmail.com>.
diff --git a/lib/dpkg/parse.c b/lib/dpkg/parse.c
index 2a96e7e46..b5e8a37c7 100644
--- a/lib/dpkg/parse.c
+++ b/lib/dpkg/parse.c
@@ -64,7 +64,6 @@ const struct fieldinfo fieldinfos[]= {
   { FIELD("Multi-Arch"),       f_multiarch,       w_multiarch,      PKGIFPOFF(multiarch)     },
   { FIELD("Source"),           f_charfield,       w_charfield,      PKGIFPOFF(source)        },
   { FIELD("Version"),          f_version,         w_version,        PKGIFPOFF(version)       },
-  { FIELD("Revision"),         f_revision,        w_null                                     },
   { FIELD("Config-Version"),   f_configversion,   w_configversion                            },
   { FIELD("Replaces"),         f_dependency,      w_dependency,     dep_replaces             },
   { FIELD("Provides"),         f_dependency,      w_dependency,     dep_provides             },
@@ -84,17 +83,13 @@ const struct fieldinfo fieldinfos[]= {
   { FIELD("Triggers-Pending"), f_trigpend,        w_trigpend                                 },
   { FIELD("Triggers-Awaited"), f_trigaw,          w_trigaw                                   },
   /* Note that aliases are added to the nicknames table. */
-  {  NULL                                                                             }
-};
-
-static const struct nickname nicknames[] = {
-  /* Note: Capitalization of these strings is important. */
-  { NICK("Recommended"),      .canon = "Recommends" },
-  { NICK("Optional"),         .canon = "Suggests" },
-  { NICK("Class"),            .canon = "Priority" },
-  { NICK("Package-Revision"), .canon = "Revision" },
-  { NICK("Package_Revision"), .canon = "Revision" },
-  { .nick = NULL }
+  { FIELD("Revision"),         f_revision,        w_null                                     },
+  { FIELD("Recommended"),      f_dependency,      w_null                                     },
+  { FIELD("Optional"),         f_dependency,      w_null                                     },
+  { FIELD("Class"),            f_priority,        w_null                                     },
+  { FIELD("Package-Revision"), f_revision,        w_null                                     },
+  { FIELD("Package_Revision"), f_revision,        w_null                                     },
+  { NULL                                                                                     }
 };
 
 /**
@@ -116,19 +111,9 @@ pkg_parse_field(struct parsedb_state *ps, struct field_state *fs,
                 void *parse_obj)
 {
   struct pkg_parse_object *pkg_obj = parse_obj;
-  const struct nickname *nick;
   const struct fieldinfo *fip;
   int *ip;
 
-  for (nick = nicknames; nick->nick; nick++)
-    if (nick->nicklen == (size_t)fs->fieldlen &&
-        strncasecmp(nick->nick, fs->fieldstart, fs->fieldlen) == 0)
-      break;
-  if (nick->nick) {
-    fs->fieldstart = nick->canon;
-    fs->fieldlen = strlen(fs->fieldstart);
-  }
-
   for (fip = fieldinfos, ip = fs->fieldencountered; fip->name; fip++, ip++)
     if (fip->namelen == (size_t)fs->fieldlen &&
         strncasecmp(fip->name, fs->fieldstart, fs->fieldlen) == 0)
diff --git a/lib/dpkg/parsedump.h b/lib/dpkg/parsedump.h
index 8e9a71056..ea29ff317 100644
--- a/lib/dpkg/parsedump.h
+++ b/lib/dpkg/parsedump.h
@@ -158,14 +158,6 @@ void parse_ensure_have_field(struct parsedb_state *ps,
 
 #define MSDOS_EOF_CHAR '\032' /* ^Z */
 
-#define NICK(name) .nick = name, .nicklen = sizeof(name) - 1
-
-struct nickname {
-  const char *nick;
-  const char *canon;
-  size_t nicklen;
-};
-
 extern const struct fieldinfo fieldinfos[];
 
 /** @} */