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Simplify sapi::file::CleanPath
PiperOrigin-RevId: 423792568 Change-Id: Ib213e619d3c3c26fa3e34b506781821f9a9b5292
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@ -14,8 +14,12 @@
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#include "sandboxed_api/util/path.h"
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#include <deque>
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#include "absl/strings/match.h"
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#include "absl/strings/str_cat.h"
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#include "absl/strings/str_join.h"
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#include "absl/strings/str_split.h"
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#include "absl/strings/strip.h"
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namespace sapi::file {
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@ -66,86 +70,34 @@ std::pair<absl::string_view, absl::string_view> SplitPath(
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}
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std::string CleanPath(const absl::string_view unclean_path) {
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auto path = std::string(unclean_path);
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const char* src = path.c_str();
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std::string::iterator dst = path.begin();
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// Check for absolute path and determine initial backtrack limit.
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const bool is_absolute_path = *src == '/';
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if (is_absolute_path) {
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*dst++ = *src++;
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while (*src == '/') {
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++src;
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int dotdot_num = 0;
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std::deque<absl::string_view> parts;
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for (absl::string_view part :
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absl::StrSplit(unclean_path, '/', absl::SkipEmpty())) {
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if (part == "..") {
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if (parts.empty()) {
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++dotdot_num;
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} else {
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parts.pop_back();
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}
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} else if (part != ".") {
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parts.push_back(part);
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}
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}
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std::string::const_iterator backtrack_limit = dst;
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// Process all parts
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while (*src) {
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bool parsed = false;
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if (src[0] == '.') {
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// 1dot ".<whateverisnext>", check for END or SEP.
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if (src[1] == '/' || !src[1]) {
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if (*++src) {
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++src;
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}
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parsed = true;
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} else if (src[1] == '.' && (src[2] == '/' || !src[2])) {
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// 2dot END or SEP (".." | "../<whateverisnext>").
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src += 2;
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if (dst != backtrack_limit) {
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// We can backtrack the previous part
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for (--dst; dst != backtrack_limit && dst[-1] != '/'; --dst) {
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// Empty.
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}
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} else if (!is_absolute_path) {
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// Failed to backtrack and we can't skip it either. Rewind and copy.
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src -= 2;
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*dst++ = *src++;
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*dst++ = *src++;
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if (*src) {
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*dst++ = *src;
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}
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// We can never backtrack over a copied "../" part so set new limit.
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backtrack_limit = dst;
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}
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if (*src) {
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++src;
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}
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parsed = true;
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}
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if (absl::StartsWith(unclean_path, "/")) {
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if (parts.empty()) {
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return "/";
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}
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// If not parsed, copy entire part until the next SEP or EOS.
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if (!parsed) {
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while (*src && *src != '/') {
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*dst++ = *src++;
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}
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if (*src) {
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*dst++ = *src++;
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}
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}
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// Skip consecutive SEP occurrences.
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while (*src == '/') {
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++src;
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}
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}
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// Calculate and check the length of the cleaned path.
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int path_length = dst - path.begin();
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if (path_length != 0) {
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// Remove trailing '/' except if it is root path ("/" ==> path_length := 1).
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if (path_length > 1 && path[path_length - 1] == '/') {
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--path_length;
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}
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path.resize(path_length);
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parts.push_front("");
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} else {
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// The cleaned path is empty; assign "." as per the spec.
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path.assign(1, '.');
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for (; dotdot_num; --dotdot_num) {
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parts.push_front("..");
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}
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if (parts.empty()) {
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return ".";
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}
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}
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return path;
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return absl::StrJoin(parts, "/");
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}
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} // namespace sapi::file
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