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authorZeno Albisser <zeno.albisser@digia.com>2013-08-15 21:46:11 +0200
committerZeno Albisser <zeno.albisser@digia.com>2013-08-15 21:46:11 +0200
commit679147eead574d186ebf3069647b4c23e8ccace6 (patch)
treefc247a0ac8ff119f7c8550879ebb6d3dd8d1ff69 /chromium/url/url_canon_relative.cc
downloadqtwebengine-chromium-679147eead574d186ebf3069647b4c23e8ccace6.tar.gz
Initial import.
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+// 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 "base/logging.h"
+#include "url/url_canon.h"
+#include "url/url_canon_internal.h"
+#include "url/url_file.h"
+#include "url/url_parse_internal.h"
+#include "url/url_util_internal.h"
+
+namespace url_canon {
+
+namespace {
+
+// Firefox does a case-sensitive compare (which is probably wrong--Mozilla bug
+// 379034), whereas IE is case-insensetive.
+//
+// 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 is ASCII.
+template<typename CHAR>
+bool AreSchemesEqual(const char* base,
+ const url_parse::Component& base_scheme,
+ const CHAR* cmp,
+ const url_parse::Component& cmp_scheme) {
+ if (base_scheme.len != cmp_scheme.len)
+ return false;
+ for (int 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;
+}
+
+#ifdef WIN32
+
+// Here, we also allow Windows paths to be represented as "/C:/" so we can be
+// consistent about URL paths beginning with slashes. This function is like
+// DoesBeginWindowsDrivePath except that it also requires a slash at the
+// beginning.
+template<typename CHAR>
+bool DoesBeginSlashWindowsDriveSpec(const CHAR* spec, int start_offset,
+ int spec_len) {
+ if (start_offset >= spec_len)
+ return false;
+ return url_parse::IsURLSlash(spec[start_offset]) &&
+ url_parse::DoesBeginWindowsDriveSpec(spec, start_offset + 1, spec_len);
+}
+
+#endif // WIN32
+
+// See IsRelativeURL in the header file for usage.
+template<typename CHAR>
+bool DoIsRelativeURL(const char* base,
+ const url_parse::Parsed& base_parsed,
+ const CHAR* url,
+ int url_len,
+ bool is_base_hierarchical,
+ bool* is_relative,
+ url_parse::Component* relative_component) {
+ *is_relative = false; // So we can default later to not relative.
+
+ // Trim whitespace and construct a new range for the substring.
+ int begin = 0;
+ url_parse::TrimURL(url, &begin, &url_len);
+ if (begin >= url_len) {
+ // Empty URLs are relative, but do nothing.
+ *relative_component = url_parse::Component(begin, 0);
+ *is_relative = true;
+ return true;
+ }
+
+#ifdef WIN32
+ // We special case paths like "C:\foo" so they can link directly to the
+ // file on Windows (IE compatability). The security domain stuff should
+ // prevent a link like this from actually being followed if its on a
+ // web page.
+ //
+ // We treat "C:/foo" as an absolute URL. We can go ahead and treat "/c:/"
+ // as relative, as this will just replace the path when the base scheme
+ // is a file and the answer will still be correct.
+ //
+ // We require strict backslashes when detecting UNC since two forward
+ // shashes should be treated a a relative URL with a hostname.
+ if (url_parse::DoesBeginWindowsDriveSpec(url, begin, url_len) ||
+ url_parse::DoesBeginUNCPath(url, begin, url_len, true))
+ return true;
+#endif // WIN32
+
+ // 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.
+ url_parse::Component scheme;
+ if (!url_parse::ExtractScheme(url, url_len, &scheme) || scheme.len == 0) {
+ // Don't allow relative URLs if the base scheme doesn't support it.
+ if (!is_base_hierarchical)
+ return false;
+
+ *relative_component = url_parse::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])) {
+ *relative_component = url_parse::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;
+
+ int colon_offset = scheme.end();
+
+ // If it's a filesystem URL, the only valid way to make it relative is not to
+ // supply a scheme. There's no equivalent to e.g. http:index.html.
+ if (url_util::CompareSchemeComponent(url, scheme, "filesystem"))
+ return true;
+
+ // 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.
+ int num_slashes = url_parse::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 = url_parse::MakeRange(colon_offset + 1, url_len);
+ return true;
+ }
+
+ // Two or more slashes after the scheme we treat as absolute.
+ 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.
+//
+// The input is assumed to be canonical, so we search only for exact slashes
+// and not backslashes as well. We also know that it's ASCII.
+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] == '/') {
+ last_slash = i;
+ break;
+ }
+ }
+ if (last_slash < 0)
+ return; // No slash.
+
+ // Copy.
+ for (int i = begin; i <= last_slash; i++)
+ output->push_back(spec[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 url_parse::Component& source_component,
+ CanonOutput* output,
+ url_parse::Component* output_component) {
+ if (source_component.len < 0) {
+ // This component is not present.
+ *output_component = url_parse::Component();
+ return;
+ }
+
+ output_component->begin = output->length();
+ int source_end = source_component.end();
+ for (int i = source_component.begin; i < source_end; i++)
+ output->push_back(source[i]);
+ output_component->len = output->length() - output_component->begin;
+}
+
+#ifdef WIN32
+
+// Called on Windows when the base URL is a file URL, this will copy the "C:"
+// to the output, if there is a drive letter and if that drive letter is not
+// being overridden by the relative URL. Otherwise, do nothing.
+//
+// It will return the index of the beginning of the next character in the
+// base to be processed: if there is a "C:", the slash after it, or if
+// there is no drive letter, the slash at the beginning of the path, or
+// the end of the base. This can be used as the starting offset for further
+// path processing.
+template<typename CHAR>
+int CopyBaseDriveSpecIfNecessary(const char* base_url,
+ int base_path_begin,
+ int base_path_end,
+ const CHAR* relative_url,
+ int path_start,
+ int relative_url_len,
+ CanonOutput* output) {
+ if (base_path_begin >= base_path_end)
+ return base_path_begin; // No path.
+
+ // If the relative begins with a drive spec, don't do anything. The existing
+ // drive spec in the base will be replaced.
+ if (url_parse::DoesBeginWindowsDriveSpec(relative_url,
+ path_start, relative_url_len)) {
+ return base_path_begin; // Relative URL path is "C:/foo"
+ }
+
+ // The path should begin with a slash (as all canonical paths do). We check
+ // if it is followed by a drive letter and copy it.
+ if (DoesBeginSlashWindowsDriveSpec(base_url,
+ base_path_begin,
+ base_path_end)) {
+ // Copy the two-character drive spec to the output. It will now look like
+ // "file:///C:" so the rest of it can be treated like a standard path.
+ output->push_back('/');
+ output->push_back(base_url[base_path_begin + 1]);
+ output->push_back(base_url[base_path_begin + 2]);
+ return base_path_begin + 3;
+ }
+
+ return base_path_begin;
+}
+
+#endif // WIN32
+
+// A subroutine of DoResolveRelativeURL, this resolves the URL knowning that
+// the input is a relative path or less (qyuery or ref).
+template<typename CHAR>
+bool DoResolveRelativePath(const char* base_url,
+ const url_parse::Parsed& base_parsed,
+ bool base_is_file,
+ const CHAR* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::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.
+ url_parse::Component path, query, ref;
+ url_parse::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.len > 0) {
+ // The path is replaced or modified.
+ int true_path_begin = output->length();
+
+ // For file: URLs on Windows, we don't want to treat the drive letter and
+ // colon as part of the path for relative file resolution when the
+ // incoming URL does not provide a drive spec. We save the true path
+ // beginning so we can fix it up after we are done.
+ int base_path_begin = base_parsed.path.begin;
+#ifdef WIN32
+ if (base_is_file) {
+ base_path_begin = CopyBaseDriveSpecIfNecessary(
+ base_url, base_parsed.path.begin, base_parsed.path.end(),
+ relative_url, relative_component.begin, relative_component.end(),
+ output);
+ // Now the output looks like either "file://" or "file:///C:"
+ // and we can start appending the rest of the path. |base_path_begin|
+ // points to the character in the base that comes next.
+ }
+#endif // WIN32
+
+ if (url_parse::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 = url_parse::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 = url_parse::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())
+ output->push_back('?');
+ 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.
+ DCHECK(false) << "Not reached";
+ return success;
+}
+
+// Resolves a relative URL that contains a host. Typically, these will
+// be of the form "//www.google.com/foo/bar?baz#ref" and the only thing which
+// should be kept from the original URL is the scheme.
+template<typename CHAR>
+bool DoResolveRelativeHost(const char* base_url,
+ const url_parse::Parsed& base_parsed,
+ const CHAR* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::Parsed* out_parsed) {
+ // Parse the relative URL, just like we would for anything following a
+ // scheme.
+ url_parse::Parsed relative_parsed; // Everything but the scheme is valid.
+ url_parse::ParseAfterScheme(&relative_url[relative_component.begin],
+ relative_component.len, relative_component.begin,
+ &relative_parsed);
+
+ // Now we can just use the replacement function to replace all the necessary
+ // parts of the old URL with the new one.
+ Replacements<CHAR> replacements;
+ replacements.SetUsername(relative_url, relative_parsed.username);
+ replacements.SetPassword(relative_url, relative_parsed.password);
+ replacements.SetHost(relative_url, relative_parsed.host);
+ replacements.SetPort(relative_url, relative_parsed.port);
+ replacements.SetPath(relative_url, relative_parsed.path);
+ replacements.SetQuery(relative_url, relative_parsed.query);
+ replacements.SetRef(relative_url, relative_parsed.ref);
+
+ return ReplaceStandardURL(base_url, base_parsed, replacements,
+ query_converter, output, out_parsed);
+}
+
+// Resolves a relative URL that happens to be an absolute file path. Examples
+// include: "//hostname/path", "/c:/foo", and "//hostname/c:/foo".
+template<typename CHAR>
+bool DoResolveAbsoluteFile(const CHAR* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::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.
+ url_parse::Parsed relative_parsed;
+ url_parse::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);
+}
+
+// TODO(brettw) treat two slashes as root like Mozilla for FTP?
+template<typename CHAR>
+bool DoResolveRelativeURL(const char* base_url,
+ const url_parse::Parsed& base_parsed,
+ bool base_is_file,
+ const CHAR* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::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.len <= 0) {
+ // On error, return the input (resolving a relative URL on a non-relative
+ // base = the base).
+ int base_len = base_parsed.Length();
+ for (int i = 0; i < base_len; i++)
+ output->push_back(base_url[i]);
+ return false;
+ }
+
+ if (relative_component.len <= 0) {
+ // Empty relative URL, leave unchanged, only removing the ref component.
+ int base_len = base_parsed.Length();
+ base_len -= base_parsed.ref.len + 1;
+ out_parsed->ref.reset();
+ output->Append(base_url, base_len);
+ return true;
+ }
+
+ int num_slashes = url_parse::CountConsecutiveSlashes(
+ relative_url, relative_component.begin, relative_component.end());
+
+#ifdef WIN32
+ // On Windows, two slashes for a file path (regardless of which direction
+ // they are) means that it's UNC. Two backslashes on any base scheme mean
+ // that it's an absolute UNC path (we use the base_is_file flag to control
+ // how strict the UNC finder is).
+ //
+ // We also allow Windows absolute drive specs on any scheme (for example
+ // "c:\foo") like IE does. There must be no preceeding slashes in this
+ // case (we reject anything like "/c:/foo") because that should be treated
+ // as a path. For file URLs, we allow any number of slashes since that would
+ // be setting the path.
+ //
+ // This assumes the absolute path resolver handles absolute URLs like this
+ // properly. url_util::DoCanonicalize does this.
+ int after_slashes = relative_component.begin + num_slashes;
+ if (url_parse::DoesBeginUNCPath(relative_url, relative_component.begin,
+ relative_component.end(), !base_is_file) ||
+ ((num_slashes == 0 || base_is_file) &&
+ url_parse::DoesBeginWindowsDriveSpec(relative_url, after_slashes,
+ relative_component.end()))) {
+ return DoResolveAbsoluteFile(relative_url, relative_component,
+ query_converter, output, out_parsed);
+ }
+#else
+ // 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. 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, out_parsed);
+ }
+#endif
+
+ // Any other double-slashes mean that this is relative to the scheme.
+ if (num_slashes >= 2) {
+ return DoResolveRelativeHost(base_url, base_parsed,
+ relative_url, relative_component,
+ 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
+
+bool IsRelativeURL(const char* base,
+ const url_parse::Parsed& base_parsed,
+ const char* fragment,
+ int fragment_len,
+ bool is_base_hierarchical,
+ bool* is_relative,
+ url_parse::Component* relative_component) {
+ return DoIsRelativeURL<char>(
+ base, base_parsed, fragment, fragment_len, is_base_hierarchical,
+ is_relative, relative_component);
+}
+
+bool IsRelativeURL(const char* base,
+ const url_parse::Parsed& base_parsed,
+ const base::char16* fragment,
+ int fragment_len,
+ bool is_base_hierarchical,
+ bool* is_relative,
+ url_parse::Component* relative_component) {
+ return DoIsRelativeURL<base::char16>(
+ base, base_parsed, fragment, fragment_len, is_base_hierarchical,
+ is_relative, relative_component);
+}
+
+bool ResolveRelativeURL(const char* base_url,
+ const url_parse::Parsed& base_parsed,
+ bool base_is_file,
+ const char* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::Parsed* out_parsed) {
+ return DoResolveRelativeURL<char>(
+ base_url, base_parsed, base_is_file, relative_url,
+ relative_component, query_converter, output, out_parsed);
+}
+
+bool ResolveRelativeURL(const char* base_url,
+ const url_parse::Parsed& base_parsed,
+ bool base_is_file,
+ const base::char16* relative_url,
+ const url_parse::Component& relative_component,
+ CharsetConverter* query_converter,
+ CanonOutput* output,
+ url_parse::Parsed* out_parsed) {
+ return DoResolveRelativeURL<base::char16>(
+ base_url, base_parsed, base_is_file, relative_url,
+ relative_component, query_converter, output, out_parsed);
+}
+
+} // namespace url_canon