version: add a feature names array to curl_version_info_data

Field feature_names contains a null-terminated sorted array of feature
names. Bitmask field features is deprecated.

Documentation is updated. Test 1177 and tests/version-scan.pl updated to
match new documentation format and extended to check feature names too.

Closes #9583

1 files changed, 129 insertions, 70 deletions

diff --git a/lib/version.c b/lib/version.c
index 44adbf8ee..b43a8bc71 100644
--- a/lib/version.c
+++ b/lib/version.c
@@ -382,93 +382,145 @@ static const char * const protocols[] = {
   NULL
 };
 
-static curl_version_info_data version_info = {
-  CURLVERSION_NOW,
-  LIBCURL_VERSION,
-  LIBCURL_VERSION_NUM,
-  OS, /* as found by configure or set by hand at build-time */
-  0 /* features is 0 by default */
-#ifdef ENABLE_IPV6
-  | CURL_VERSION_IPV6
+/*
+ * Feature presence run-time check functions.
+ *
+ * Warning: the value returned by these should not change between
+ * curl_global_init() and curl_global_cleanup() calls.
+ */
+
+#if defined(USE_LIBIDN2)
+static int idn_present(curl_version_info_data *info)
+{
+  return info->libidn != NULL;
+}
+#else
+#define idn_present     NULL
 #endif
-#ifdef USE_SSL
-  | CURL_VERSION_SSL
+
+#if defined(USE_SSL) && !defined(CURL_DISABLE_PROXY)
+static int https_proxy_present(curl_version_info_data *info)
+{
+  (void) info;
+  return Curl_ssl_supports(NULL, SSLSUPP_HTTPS_PROXY);
+}
 #endif
-#ifdef USE_NTLM
-  | CURL_VERSION_NTLM
+
+/*
+ * Features table.
+ *
+ * Keep the features alphabetically sorted.
+ * Use FEATURE() macro to define an entry: this allows documentation check.
+ */
+
+#define FEATURE(name, present, bitmask) {(name), (present), (bitmask)}
+
+struct feat {
+  const char *name;
+  int        (*present)(curl_version_info_data *info);
+  int        bitmask;
+};
+
+static const struct feat features_table[] = {
+#ifndef CURL_DISABLE_ALTSVC
+  FEATURE("alt-svc",     NULL,                CURL_VERSION_ALTSVC),
 #endif
-#if !defined(CURL_DISABLE_HTTP) && defined(USE_NTLM) && \
-  defined(NTLM_WB_ENABLED)
-  | CURL_VERSION_NTLM_WB
+#ifdef CURLRES_ASYNCH
+  FEATURE("AsynchDNS",   NULL,                CURL_VERSION_ASYNCHDNS),
 #endif
-#ifdef USE_SPNEGO
-  | CURL_VERSION_SPNEGO
+#ifdef HAVE_BROTLI
+  FEATURE("brotli",      NULL,                CURL_VERSION_BROTLI),
 #endif
-#ifdef USE_KERBEROS5
-  | CURL_VERSION_KERBEROS5
+#ifdef DEBUGBUILD
+  FEATURE("Debug",       NULL,                CURL_VERSION_DEBUG),
+#endif
+#ifdef USE_GSASL
+  FEATURE("gsasl",       NULL,                CURL_VERSION_GSASL),
 #endif
 #ifdef HAVE_GSSAPI
-  | CURL_VERSION_GSSAPI
+  FEATURE("GSS-API",     NULL,                CURL_VERSION_GSSAPI),
 #endif
-#ifdef USE_WINDOWS_SSPI
-  | CURL_VERSION_SSPI
+#ifndef CURL_DISABLE_HSTS
+  FEATURE("HSTS",        NULL,                CURL_VERSION_HSTS),
 #endif
-#ifdef HAVE_LIBZ
-  | CURL_VERSION_LIBZ
+#if defined(USE_NGHTTP2) || defined(USE_HYPER)
+  FEATURE("HTTP2",       NULL,                CURL_VERSION_HTTP2),
 #endif
-#ifdef DEBUGBUILD
-  | CURL_VERSION_DEBUG
+#if defined(ENABLE_QUIC)
+  FEATURE("HTTP3",       NULL,                CURL_VERSION_HTTP3),
 #endif
-#ifdef CURLDEBUG
-  | CURL_VERSION_CURLDEBUG
+#if defined(USE_SSL) && !defined(CURL_DISABLE_PROXY)
+  FEATURE("HTTPS-proxy", https_proxy_present, CURL_VERSION_HTTPS_PROXY),
 #endif
-#ifdef CURLRES_ASYNCH
-  | CURL_VERSION_ASYNCHDNS
+#if defined(USE_LIBIDN2) || defined(USE_WIN32_IDN)
+  FEATURE("IDN",         idn_present,         CURL_VERSION_IDN),
+#endif
+#ifdef ENABLE_IPV6
+  FEATURE("IPv6",        NULL,                CURL_VERSION_IPV6),
+#endif
+#ifdef USE_KERBEROS5
+  FEATURE("Kerberos",    NULL,                CURL_VERSION_KERBEROS5),
 #endif
 #if (SIZEOF_CURL_OFF_T > 4) && \
     ( (SIZEOF_OFF_T > 4) || defined(USE_WIN32_LARGE_FILES) )
-  | CURL_VERSION_LARGEFILE
+  FEATURE("Largefile",   NULL,                CURL_VERSION_LARGEFILE),
 #endif
-#if defined(WIN32) && defined(UNICODE) && defined(_UNICODE)
-  | CURL_VERSION_UNICODE
-#endif
-#if defined(USE_TLS_SRP)
-  | CURL_VERSION_TLSAUTH_SRP
+#ifdef HAVE_LIBZ
+  FEATURE("libz",        NULL,                CURL_VERSION_LIBZ),
 #endif
-#if defined(USE_NGHTTP2) || defined(USE_HYPER)
-  | CURL_VERSION_HTTP2
+#ifdef CURL_WITH_MULTI_SSL
+  FEATURE("MultiSSL",    NULL,                CURL_VERSION_MULTI_SSL),
 #endif
-#if defined(ENABLE_QUIC)
-  | CURL_VERSION_HTTP3
+#ifdef USE_NTLM
+  FEATURE("NTLM",        NULL,                CURL_VERSION_NTLM),
 #endif
-#if defined(USE_UNIX_SOCKETS)
-  | CURL_VERSION_UNIX_SOCKETS
+#if !defined(CURL_DISABLE_HTTP) && defined(USE_NTLM) && \
+  defined(NTLM_WB_ENABLED)
+  FEATURE("NTLM_WB",     NULL,                CURL_VERSION_NTLM_WB),
 #endif
 #if defined(USE_LIBPSL)
-  | CURL_VERSION_PSL
+  FEATURE("PSL",         NULL,                CURL_VERSION_PSL),
+#endif
+#ifdef USE_SPNEGO
+  FEATURE("SPNEGO",      NULL,                CURL_VERSION_SPNEGO),
 #endif
-#if defined(CURL_WITH_MULTI_SSL)
-  | CURL_VERSION_MULTI_SSL
+#ifdef USE_SSL
+  FEATURE("SSL",         NULL,                CURL_VERSION_SSL),
 #endif
-#if defined(HAVE_BROTLI)
-  | CURL_VERSION_BROTLI
+#ifdef USE_WINDOWS_SSPI
+  FEATURE("SSPI",        NULL,                CURL_VERSION_SSPI),
 #endif
-#if defined(HAVE_ZSTD)
-  | CURL_VERSION_ZSTD
+#ifdef GLOBAL_INIT_IS_THREADSAFE
+  FEATURE("threadsafe",  NULL,                CURL_VERSION_THREADSAFE),
 #endif
-#ifndef CURL_DISABLE_ALTSVC
-  | CURL_VERSION_ALTSVC
+#ifdef USE_TLS_SRP
+  FEATURE("TLS-SRP",     NULL,                CURL_VERSION_TLSAUTH_SRP),
 #endif
-#ifndef CURL_DISABLE_HSTS
-  | CURL_VERSION_HSTS
+#ifdef CURLDEBUG
+  FEATURE("TrackMemory", NULL,                CURL_VERSION_CURLDEBUG),
+#endif
+#if defined(WIN32) && defined(UNICODE) && defined(_UNICODE)
+  FEATURE("Unicode",     NULL,                CURL_VERSION_UNICODE),
 #endif
-#if defined(USE_GSASL)
-  | CURL_VERSION_GSASL
+#ifdef USE_UNIX_SOCKETS
+  FEATURE("UnixSockets", NULL,                CURL_VERSION_UNIX_SOCKETS),
 #endif
-#if defined(GLOBAL_INIT_IS_THREADSAFE)
-  | CURL_VERSION_THREADSAFE
+#ifdef HAVE_ZSTD
+  FEATURE("zstd",        NULL,                CURL_VERSION_ZSTD),
 #endif
-  ,
+  {NULL,             NULL,                0}
+};
+
+static const char *feature_names[sizeof(features_table) /
+                                 sizeof(features_table[0])] = {NULL};
+
+
+static curl_version_info_data version_info = {
+  CURLVERSION_NOW,
+  LIBCURL_VERSION,
+  LIBCURL_VERSION_NUM,
+  OS,   /* as found by configure or set by hand at build-time */
+  0,    /* features bitmask is built at run-time */
   NULL, /* ssl_version */
   0,    /* ssl_version_num, this is kept at zero */
   NULL, /* zlib_version */
@@ -496,11 +548,16 @@ static curl_version_info_data version_info = {
   0,    /* zstd_ver_num */
   NULL, /* zstd version */
   NULL, /* Hyper version */
-  NULL  /* gsasl version */
+  NULL, /* gsasl version */
+  feature_names
 };
 
 curl_version_info_data *curl_version_info(CURLversion stamp)
 {
+  size_t n;
+  const struct feat *p;
+  int features = 0;
+
 #if defined(USE_SSH)
   static char ssh_buffer[80];
 #endif
@@ -518,15 +575,11 @@ curl_version_info_data *curl_version_info(CURLversion stamp)
   static char zstd_buffer[80];
 #endif
 
+  (void)stamp; /* avoid compiler warnings, we don't use this */
+
 #ifdef USE_SSL
   Curl_ssl_version(ssl_buffer, sizeof(ssl_buffer));
   version_info.ssl_version = ssl_buffer;
-#ifndef CURL_DISABLE_PROXY
-  if(Curl_ssl_supports(NULL, SSLSUPP_HTTPS_PROXY))
-    version_info.features |= CURL_VERSION_HTTPS_PROXY;
-  else
-    version_info.features &= ~CURL_VERSION_HTTPS_PROXY;
-#endif
 #endif
 
 #ifdef HAVE_LIBZ
@@ -544,10 +597,6 @@ curl_version_info_data *curl_version_info(CURLversion stamp)
   /* This returns a version string if we use the given version or later,
      otherwise it returns NULL */
   version_info.libidn = idn2_check_version(IDN2_VERSION);
-  if(version_info.libidn)
-    version_info.features |= CURL_VERSION_IDN;
-#elif defined(USE_WIN32_IDN)
-  version_info.features |= CURL_VERSION_IDN;
 #endif
 
 #if defined(USE_SSH)
@@ -597,6 +646,16 @@ curl_version_info_data *curl_version_info(CURLversion stamp)
   }
 #endif
 
-  (void)stamp; /* avoid compiler warnings, we don't use this */
+  /* Get available features, build bitmask and names array. */
+  n = 0;
+  for(p = features_table; p->name; p++)
+    if(!p->present || p->present(&version_info)) {
+      features |= p->bitmask;
+      feature_names[n++] = p->name;
+    }
+
+  feature_names[n] = NULL;  /* Terminate array. */
+  version_info.features = features;
+
   return &version_info;
 }