diff options
Diffstat (limited to 'Firestore/core/src/firebase/firestore/model/field_path.cc')
-rw-r--r-- | Firestore/core/src/firebase/firestore/model/field_path.cc | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/Firestore/core/src/firebase/firestore/model/field_path.cc b/Firestore/core/src/firebase/firestore/model/field_path.cc new file mode 100644 index 0000000..6c40600 --- /dev/null +++ b/Firestore/core/src/firebase/firestore/model/field_path.cc @@ -0,0 +1,176 @@ +/* + * Copyright 2018 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "Firestore/core/src/firebase/firestore/model/field_path.h" + +#include <algorithm> +#include <utility> + +#include "Firestore/core/src/firebase/firestore/util/firebase_assert.h" +#include "absl/strings/str_join.h" +#include "absl/strings/str_replace.h" +#include "absl/strings/str_split.h" + +namespace firebase { +namespace firestore { +namespace model { + +namespace { + +// TODO(varconst): move to C++ equivalent of FSTDocumentKey.{h,cc} +const char* const kDocumentKeyPath = "__name__"; + +/** + * True if the string could be used as a segment in a field path without + * escaping. Valid identifies follow the regex [a-zA-Z_][a-zA-Z0-9_]* + */ +bool IsValidIdentifier(const std::string& segment) { + if (segment.empty()) { + return false; + } + + // Note: strictly speaking, only digits are guaranteed by the Standard to + // be a contiguous range, while alphabetic characters may have gaps. Ignoring + // this peculiarity, because it doesn't affect the platforms that Firestore + // supports. + const unsigned char first = segment.front(); + if (first != '_' && (first < 'a' || first > 'z') && + (first < 'A' || first > 'Z')) { + return false; + } + for (int i = 1; i != segment.size(); ++i) { + const unsigned char c = segment[i]; + if (c != '_' && (c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && + (c < '0' || c > '9')) { + return false; + } + } + + return true; +} + +} // namespace + +FieldPath FieldPath::FromServerFormat(const absl::string_view path) { + // TODO(b/37244157): Once we move to v1beta1, we should make this more + // strict. Right now, it allows non-identifier path components, even if they + // aren't escaped. Technically, this will mangle paths with backticks in + // them used in v1alpha1, but that's fine. + + SegmentsT segments; + std::string segment; + segment.reserve(path.size()); + + // string_view doesn't have a c_str() method, because it might not be + // null-terminated. Assertions expect C strings, so construct std::string on + // the fly, so that c_str() might be called on it. + const auto to_string = [](const absl::string_view view) { + return std::string{view.data(), view.data() + view.size()}; + }; + const auto finish_segment = [&segments, &segment, &path, &to_string] { + FIREBASE_ASSERT_MESSAGE( + !segment.empty(), + "Invalid field path (%s). Paths must not be empty, begin with " + "'.', end with '.', or contain '..'", + to_string(path).c_str()); + // Move operation will clear segment, but capacity will remain the same + // (not, strictly speaking, required by the standard, but true in practice). + segments.push_back(std::move(segment)); + }; + + // Inside backticks, dots are treated literally. + bool inside_backticks = false; + int i = 0; + while (i < path.size()) { + const char c = path[i]; + // std::string (and string_view) may contain embedded nulls. For full + // compatibility with Objective C behavior, finish upon encountering the + // first terminating null. + if (c == '\0') { + break; + } + + switch (c) { + case '.': + if (!inside_backticks) { + finish_segment(); + } else { + segment += c; + } + break; + + case '`': + inside_backticks = !inside_backticks; + break; + + case '\\': + // TODO(b/37244157): Make this a user-facing exception once we + // finalize field escaping. + FIREBASE_ASSERT_MESSAGE(i + 1 != path.size(), + "Trailing escape characters not allowed in %s", + to_string(path).c_str()); + ++i; + segment += path[i]; + break; + + default: + segment += c; + break; + } + ++i; + } + finish_segment(); + + FIREBASE_ASSERT_MESSAGE(!inside_backticks, "Unterminated ` in path %s", + to_string(path).c_str()); + + return FieldPath{std::move(segments)}; +} + +const FieldPath& FieldPath::EmptyPath() { + static const FieldPath empty_path; + return empty_path; +} + +const FieldPath& FieldPath::KeyFieldPath() { + static const FieldPath key_field_path{kDocumentKeyPath}; + return key_field_path; +} + +bool FieldPath::IsKeyFieldPath() const { + return size() == 1 && first_segment() == kDocumentKeyPath; +} + +std::string FieldPath::CanonicalString() const { + const auto escaped_segment = [](const std::string& segment) { + auto escaped = absl::StrReplaceAll(segment, {{"\\", "\\\\"}, {"`", "\\`"}}); + const bool needs_escaping = !IsValidIdentifier(escaped); + if (needs_escaping) { + escaped.insert(escaped.begin(), '`'); + escaped.push_back('`'); + } + return escaped; + }; + return absl::StrJoin( + begin(), end(), ".", + [escaped_segment](std::string* out, const std::string& segment) { + out->append(escaped_segment(segment)); + }); +} + +} // namespace model +} // namespace firestore +} // namespace firebase |