1 files changed, 132 insertions, 0 deletions
diff --git a/src/libwebvi/urlutils.c b/src/libwebvi/urlutils.c
new file mode 100644
index 0000000..de64e06
--- /dev/null
+++ b/src/libwebvi/urlutils.c
@@ -0,0 +1,132 @@
+#include <string.h>
+#include "urlutils.h"
+
+static const gchar *skip_scheme(const char *url);
+static gboolean is_scheme_character(gchar c);
+
+gchar *relative_url_to_absolute(const gchar *baseurl, const gchar *href) {
+  gchar *absolute;
+  gchar *prefix;
+  const gchar *postfix = href;
+  if ((href[0] == '/') && (href[1] == '/')) {
+    gchar *scheme = url_scheme(baseurl);
+    prefix = g_strconcat(scheme, ":", NULL);
+    g_free(scheme);
+  } else if (href[0] == '/') {
+    prefix = url_root(baseurl);
+    if (g_str_has_suffix(prefix, "/")) {
+      postfix = href+1;
+    }
+  } else if (href[0] == '?') {
+    prefix = url_path_including_file(baseurl);
+  } else if (href[0] =='#') {
+    prefix = url_path_and_query(baseurl);
+  } else if (strstr(href, "://") == NULL) {
+    prefix = url_path_dirname(baseurl);
+  } else {
+    // href is absolute
+    prefix = NULL;
+  }
+
+  if (prefix) {
+    absolute = g_strconcat(prefix, postfix, NULL);
+    g_free(prefix);
+  } else {
+    absolute = g_strdup(href);
+  }
+
+  return absolute;
+}
+
+gchar *url_scheme(const gchar *url) {
+  if (!url)
+    return NULL;
+
+  const gchar *scheme_end = skip_scheme(url);
+  if (scheme_end == url) {
+    // no scheme
+    return g_strdup("");
+  } else {
+    // scheme found
+    // Do not include :// in the return value
+    g_assert(scheme_end >= url+3);
+    return g_strndup(url, scheme_end-3 - url);
+  }
+}
+
+gchar *url_root(const gchar *url) {
+  if (!url)
+    return NULL;
+
+  const gchar *authority = skip_scheme(url);
+  size_t authority_len = strcspn(authority, "/?#");
+  const gchar *authority_end = authority + authority_len;
+  gchar *root_without_slash = g_strndup(url, authority_end - url);
+  gchar *root = g_strconcat(root_without_slash, "/", NULL);
+  g_free(root_without_slash);
+  return root;
+}
+
+gchar *url_path_including_file(const gchar *url) {
+  if (!url)
+    return NULL;
+
+  const gchar *scheme_end = skip_scheme(url);
+  size_t path_len = strcspn(scheme_end, "?#");
+  const gchar *end = scheme_end + path_len;
+  gchar *path = g_strndup(url, end - url);
+  if (memchr(scheme_end, '/', path_len) == NULL) {
+    gchar *path2 = g_strconcat(path, "/", NULL);
+    g_free(path);
+    path = path2;
+  }
+
+  return path;
+}
+
+gchar *url_path_dirname(const gchar *url) {
+  if (!url)
+    return NULL;
+
+  const gchar *scheme_end = skip_scheme(url);
+  size_t path_len = strcspn(scheme_end, "?#");
+  const gchar *p = scheme_end + path_len;
+  while ((p >= url) && (*p != '/')) {
+    p--;
+  }
+
+  if (*p == '/') {
+    return g_strndup(url, (p+1) - url);
+  } else {
+    return g_strdup("/");
+  }
+}
+
+gchar *url_path_and_query(const gchar *url) {
+  if (!url)
+    return NULL;
+
+  const gchar *scheme_end = skip_scheme(url);
+  size_t path_len = strcspn(scheme_end, "#");
+  const gchar *end = scheme_end + path_len;
+  return g_strndup(url, end - url);
+}
+
+const gchar *skip_scheme(const char *url) {
+  const gchar *c = url;
+  while (is_scheme_character(*c)) {
+    c++;
+  }
+
+  if (strncmp(c, "://", 3) == 0) {
+    // scheme found
+    return c + 3;
+  } else {
+    // schemeless url
+    return url;
+  }
+}
+
+gboolean is_scheme_character(gchar c) {
+  return g_ascii_isalnum(c) || (c == '+') || (c == '-') || (c == '.');
+}