blob: 1f9718660f35ebb56eae2b9b033fe2b86c365d87 [file] [log] [blame]
// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Canonicalizer functions for working with and resolving relative URLs.
#include <iostream>
#include "src/lib/fxl/logging.h"
#include "src/lib/url/url_canon.h"
#include "src/lib/url/url_canon_internal.h"
#include "src/lib/url/url_constants.h"
#include "src/lib/url/url_file.h"
#include "src/lib/url/url_parse_internal.h"
#include "src/lib/url/url_util_internal.h"
namespace url {
namespace {
// Firefox does a case-sensitive compare (which is probably wrong--Mozilla bug
// 379034), whereas IE is case-insensitive.
// We choose to be more permissive like IE. We don't need to worry about
// unescaping or anything here: neither IE or Firefox allow this. We also
// don't have to worry about invalid scheme characters since we are comparing
// against the canonical scheme of the base.
// The base URL should always be canonical, therefore it should be ASCII.
bool AreSchemesEqual(const char* base, const Component& base_scheme, const char* cmp,
const Component& cmp_scheme) {
if (base_scheme.len() != cmp_scheme.len())
return false;
for (size_t i = 0; i < base_scheme.len(); i++) {
// We assume the base is already canonical, so we don't have to
// canonicalize it.
if (CanonicalSchemeChar(cmp[cmp_scheme.begin + i]) != base[base_scheme.begin + i])
return false;
return true;
// Copies all characters in the range [begin, end) of |spec| to the output,
// up until and including the last slash. There should be a slash in the
// range, if not, nothing will be copied.
// For stardard URLs the input should be canonical, but when resolving relative
// URLs on a non-standard base (like "data:") the input can be anything.
void CopyToLastSlash(const char* spec, int begin, int end, CanonOutput* output) {
// Find the last slash.
int last_slash = -1;
for (int i = end - 1; i >= begin; i--) {
if (spec[i] == '/' || spec[i] == '\\') {
last_slash = i;
if (last_slash < 0)
return; // No slash.
// Copy.
for (int i = begin; i <= last_slash; i++)
// Copies a single component from the source to the output. This is used
// when resolving relative URLs and a given component is unchanged. Since the
// source should already be canonical, we don't have to do anything special,
// and the input is ASCII.
void CopyOneComponent(const char* source, const Component& source_component, CanonOutput* output,
Component* output_component) {
if (!source_component.is_valid()) {
// This component is not present.
*output_component = Component();
output_component->begin = output->length();
int source_end = source_component.end();
for (int i = source_component.begin; i < source_end; i++)
output_component->set_len(output->length() - output_component->begin);
// A subroutine of DoResolveRelativeURL, this resolves the URL knowning that
// the input is a relative path or less (qyuery or ref).
bool DoResolveRelativePath(const char* base_url, const Parsed& base_parsed, bool base_is_file,
const char* relative_url, const Component& relative_component,
CharsetConverter* query_converter, CanonOutput* output,
Parsed* out_parsed) {
bool success = true;
// We know the authority section didn't change, copy it to the output. We
// also know we have a path so can copy up to there.
Component path, query, ref;
ParsePathInternal(relative_url, relative_component, &path, &query, &ref);
// Canonical URLs always have a path, so we can use that offset.
output->Append(base_url, base_parsed.path.begin);
if (path.is_nonempty()) {
// The path is replaced or modified.
int true_path_begin = output->length();
int base_path_begin = base_parsed.path.begin;
if (IsURLSlash(relative_url[path.begin])) {
// Easy case: the path is an absolute path on the server, so we can
// just replace everything from the path on with the new versions.
// Since the input should be canonical hierarchical URL, we should
// always have a path.
success &= CanonicalizePath(relative_url, path, output, &out_parsed->path);
} else {
// Relative path, replace the query, and reference. We take the
// original path with the file part stripped, and append the new path.
// The canonicalizer will take care of resolving ".." and "."
int path_begin = output->length();
CopyToLastSlash(base_url, base_path_begin, base_parsed.path.end(), output);
success &= CanonicalizePartialPath(relative_url, path, path_begin, output);
out_parsed->path = MakeRange(path_begin, output->length());
// Copy the rest of the stuff after the path from the relative path.
// Finish with the query and reference part (these can't fail).
CanonicalizeQuery(relative_url, query, query_converter, output, &out_parsed->query);
CanonicalizeRef(relative_url, ref, output, &out_parsed->ref);
// Fix the path beginning to add back the "C:" we may have written above.
out_parsed->path = MakeRange(true_path_begin, out_parsed->path.end());
return success;
// If we get here, the path is unchanged: copy to output.
CopyOneComponent(base_url, base_parsed.path, output, &out_parsed->path);
if (query.is_valid()) {
// Just the query specified, replace the query and reference (ignore
// failures for refs)
CanonicalizeQuery(relative_url, query, query_converter, output, &out_parsed->query);
CanonicalizeRef(relative_url, ref, output, &out_parsed->ref);
return success;
// If we get here, the query is unchanged: copy to output. Note that the
// range of the query parameter doesn't include the question mark, so we
// have to add it manually if there is a component.
if (base_parsed.query.is_valid())
CopyOneComponent(base_url, base_parsed.query, output, &out_parsed->query);
if (ref.is_valid()) {
// Just the reference specified: replace it (ignoring failures).
CanonicalizeRef(relative_url, ref, output, &out_parsed->ref);
return success;
// We should always have something to do in this function, the caller checks
// that some component is being replaced.
FX_DCHECK(false) << "Not reached";
return success;
// Resolves a relative URL that happens to be an absolute file path. Examples
// include: "//hostname/path", "/c:/foo", and "//hostname/c:/foo".
bool DoResolveAbsoluteFile(const char* relative_url, const Component& relative_component,
CharsetConverter* query_converter, CanonOutput* output,
Parsed* out_parsed) {
// Parse the file URL. The file URl parsing function uses the same logic
// as we do for determining if the file is absolute, in which case it will
// not bother to look for a scheme.
Parsed relative_parsed;
ParseFileURL(&relative_url[relative_component.begin], relative_component.len(), &relative_parsed);
return CanonicalizeFileURL(&relative_url[relative_component.begin], relative_component.len(),
relative_parsed, query_converter, output, out_parsed);
} // namespace
// See IsRelativeURL in the header file for usage.
bool IsRelativeURL(const char* base, const Parsed& base_parsed, const char* url, size_t url_len,
bool is_base_hierarchical, bool* is_relative, Component* relative_component) {
*is_relative = false; // So we can default later to not relative.
// Trim whitespace and construct a new range for the substring.
size_t begin = 0;
TrimURL(url, &begin, &url_len);
if (begin >= url_len) {
// Empty URLs are relative, but do nothing.
*relative_component = Component(begin, 0);
*is_relative = true;
return true;
// See if we've got a scheme, if not, we know this is a relative URL.
// BUT, just because we have a scheme, doesn't make it absolute.
// "http:foo.html" is a relative URL with path "foo.html". If the scheme is
// empty, we treat it as relative (":foo"), like IE does.
Component scheme;
const bool scheme_is_empty = !ExtractScheme(url, url_len, &scheme) || scheme.len() == 0;
if (scheme_is_empty) {
if (url[begin] == '#') {
// |url| is a bare fragment (e.g. "#foo"). This can be resolved against
// any base. Fall-through.
} else if (!is_base_hierarchical) {
// Don't allow relative URLs if the base scheme doesn't support it.
return false;
*relative_component = MakeRange(begin, url_len);
*is_relative = true;
return true;
// If the scheme isn't valid, then it's relative.
int scheme_end = scheme.end();
for (int i = scheme.begin; i < scheme_end; i++) {
if (!CanonicalSchemeChar(url[i])) {
if (!is_base_hierarchical) {
// Don't allow relative URLs if the base scheme doesn't support it.
return false;
*relative_component = MakeRange(begin, url_len);
*is_relative = true;
return true;
// If the scheme is not the same, then we can't count it as relative.
if (!AreSchemesEqual(base, base_parsed.scheme, url, scheme))
return true;
// When the scheme that they both share is not hierarchical, treat the
// incoming scheme as absolute (this way with the base of "data:foo",
// "data:bar" will be reported as absolute.
if (!is_base_hierarchical)
return true;
size_t colon_offset = scheme.end();
// ExtractScheme guarantees that the colon immediately follows what it
// considers to be the scheme. CountConsecutiveSlashes will handle the
// case where the begin offset is the end of the input.
size_t num_slashes = CountConsecutiveSlashes(url, colon_offset + 1, url_len);
if (num_slashes == 0 || num_slashes == 1) {
// No slashes means it's a relative path like "http:foo.html". One slash
// is an absolute path. "http:/home/foo.html"
*is_relative = true;
*relative_component = MakeRange(colon_offset + 1, url_len);
return true;
// Two or more slashes after the scheme we treat as absolute.
return true;
// TODO(brettw) treat two slashes as root like Mozilla for FTP?
bool ResolveRelativeURL(const char* base_url, const Parsed& base_parsed, bool base_is_file,
const char* relative_url, const Component& relative_component,
CharsetConverter* query_converter, CanonOutput* output,
Parsed* out_parsed) {
// Starting point for our output parsed. We'll fix what we change.
*out_parsed = base_parsed;
// Sanity check: the input should have a host or we'll break badly below.
// We can only resolve relative URLs with base URLs that have hosts and
// paths (even the default path of "/" is OK).
// We allow hosts with no length so we can handle file URLs, for example.
if (base_parsed.path.is_invalid_or_empty()) {
// On error, return the input (resolving a relative URL on a non-relative
// base = the base).
size_t base_len = base_parsed.Length();
for (size_t i = 0; i < base_len; i++)
return false;
if (relative_component.is_invalid_or_empty()) {
// Empty relative URL, leave unchanged, only removing the ref component.
size_t base_len = base_parsed.Length();
if (base_parsed.ref.is_valid()) {
base_len -= base_parsed.ref.len() + 1;
output->Append(base_url, base_len);
return true;
size_t num_slashes =
CountConsecutiveSlashes(relative_url, relative_component.begin, relative_component.end());
// Other platforms need explicit handling for file: URLs with multiple
// slashes because the generic scheme parsing always extracts a host, but a
// file: URL only has a host if it has exactly 2 slashes. Even if it does
// have a host, we want to use the special host detection logic for file
// URLs provided by DoResolveAbsoluteFile(), as opposed to the generic host
// detection logic, for consistency with parsing file URLs from scratch.
// This also handles the special case where the URL is only slashes,
// since that doesn't have a host part either.
if (base_is_file && (num_slashes >= 2 || num_slashes == relative_component.len())) {
return DoResolveAbsoluteFile(relative_url, relative_component, query_converter, output,
// Any other double-slashes mean that this is relative to the scheme.
if (num_slashes >= 2) {
// Make & parse an url with base_url's scheme and everything else from
// relative_url.
std::string new_url;
new_url.reserve(base_parsed.scheme.len() + 1 + relative_component.len());
new_url.append(&base_url[base_parsed.scheme.begin], base_parsed.scheme.len());
new_url.append(&relative_url[relative_component.begin], relative_component.len());
Parsed new_parsed;
ParseStandardURL(new_url.c_str(), new_url.size(), &new_parsed);
// Canonicalize the combined url.
return CanonicalizeStandardURL(new_url.c_str(), new_url.size(), new_parsed, query_converter,
output, out_parsed);
// When we get here, we know that the relative URL is on the same host.
return DoResolveRelativePath(base_url, base_parsed, base_is_file, relative_url,
relative_component, query_converter, output, out_parsed);
} // namespace url