mirror of
https://github.com/simdjson/simdjson
synced 2026-06-08 17:27:07 +00:00
Daniel Lemire
+3
-3
@@ -452,7 +452,7 @@ support for users who avoid exceptions. See [the simdjson error handling documen
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* **Field Access:** To get the value of the "foo" field in an object, use `object["foo"]`. This will
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scan through the object looking for the field with the matching string, doing a character-by-character
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comparison. It may generate the error `simdjson::NO_SUCH_FIELD` if there is no such key in the object, it may throw an exception (see [Error handling](#error-handling)). For efficiency reason, you should avoid looking up the same field repeatedly: e.g., do
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not do `object["foo"]` followed by `object["foo"]` with the same `object` instance. Generally, you should not mix and match iterating through an object (`for(auto field : object) {...}`) and key accesses (`object["foo"]`): if you need to iterate through an object after a key access, you need to call `reset()` on the object. Whenever you call `reset()`, you need to keep in mind that though you can iterate over the array repeatedly, values should be consumed only once (e.g., repeatedly calling `unescaped_key()` on the same key is forbidden). Keep in mind that On-Demand does not buffer or save the result of the parsing: if you repeatedly access `object["foo"]`, then it must repeatedly seek the key and parse the content. The library does not provide a distinct function to check if a key is present, instead we recommend you attempt to access the key: e.g., by doing `ondemand::value val{}; if (!object["foo"].get(val)) {...}`, you have that `val` contains the requested value inside the if clause. It is your responsibility as a user to temporarily keep a reference to the value (`auto v = object["foo"]`), or to consume the content and store it in your own data structures. If you consume an
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not do `object["foo"]` followed by `object["foo"]` with the same `object` instance. Generally, you should not mix and match iterating through an object (`for(auto field : object) {...}`) and key accesses (`object["foo"]`): if you need to iterate through an object after a key access, you need to call `reset()` on the object. Whenever you call `reset()`, you need to keep in mind that though you can iterate over the array repeatedly, values should be consumedonly once (e.g., repeatedly calling `unescaped_key()` on the same key is forbidden). Keep in mind that On-Demand does not buffer or save the result of the parsing: if you repeatedly access `object["foo"]`, then it must repeatedly seek the key and parse the content. The library does not provide a distinct function to check if a key is present, instead we recommend you attempt to access the key: e.g., by doing `ondemand::value val{}; if (!object["foo"].get(val)) {...}`, you have that `val` contains the requested value inside the if clause. It is your responsibility as a user to temporarily keep a reference to the value (`auto v = object["foo"]`), or to consume the content and store it in your own data structures. If you consume an
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object twice: `std::string_view(object["foo"]` followed by `std::string_view(object["foo"]` then your code
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is in error. Furthermore, you can only consume one field at a time, on the same object. The
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value instance you get from `content["bids"]` becomes invalid when you call `content["asks"]`.
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@@ -1581,7 +1581,7 @@ JSON Pointer
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The simdjson library also supports [JSON pointer](https://tools.ietf.org/html/rfc6901) through the `at_pointer()` method, letting you reach further down into the document in a single call. JSON Pointer is supported by both the [DOM approach](https://github.com/simdjson/simdjson/blob/master/doc/dom.md#json-pointer) as well as the On-Demand approach.
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**Note:** The On-Demand implementation of JSON Pointer relies on `find_field` which implies that it does not unescape keys when matching.
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**Note:** When matching keys, we do a byte-by-byte comparison. We do not unescape keys when matching.
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Consider the following example:
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@@ -1696,7 +1696,7 @@ be represented as `value` instances. You can check that a document is a scalar w
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JSONPath
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------------
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The simdjson library supports a subset of [JSONPath](https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
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The simdjson library supports a subset of [JSONPath](https://www.rfc-editor.org/rfc/rfc9535) (RFC 9535) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
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This implementation relies on `at_path()` converting its argument to JSON Pointer and then calling `at_pointer`, which makes use of
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[`rewind`](#rewind) to reset the parser at the beginning of the document. Hence, it invalidates all previously parsed values, objects
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+1
-1
@@ -313,7 +313,7 @@ JSONPath
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------------
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The simdjson library supports a subset of [JSONPath](https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
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The simdjson library supports a subset of [JSONPath](https://www.rfc-editor.org/rfc/rfc9535) (RFC 9535) through the `at_path()` method, allowing you to reach further into the document in a single call. The subset of JSONPath that is implemented is the subset that is trivially convertible into the JSON Pointer format, using `.` to access a field and `[]` to access a specific index.
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Consider the following example:
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@@ -111,7 +111,7 @@ public:
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inline simdjson_result<element> at_pointer(std::string_view json_pointer) const noexcept;
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/**
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* Recursive function which processes the json path of each child element
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* Recursive function which processes the JSON path of each child element
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*/
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inline void process_json_path_of_child_elements(std::vector<element>::iterator& current, std::vector<element>::iterator& end, const std::string_view& path_suffix, std::vector<element>& accumulator) const noexcept;
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@@ -408,7 +408,7 @@ public:
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* JSONPath queries that trivially convertible to JSON Pointer queries: key
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* names and array indices.
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*
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* https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
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* https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
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*
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* @return The value associated with the given JSONPath expression, or:
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* - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails
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@@ -186,7 +186,7 @@ inline simdjson_result<std::vector<element>> object::at_path_with_wildcard(std::
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}
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if (i >= json_path.size() || (json_path[i] != '.' && json_path[i] != '[')) {
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// expect json path to always start with $ but this isn't currently
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// expect JSONPath expressions to always start with $ but this isn't currently
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// expected in jsonpathutil.h.
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return INVALID_JSON_POINTER;
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}
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@@ -175,7 +175,7 @@ public:
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inline simdjson_result<element> at_pointer(std::string_view json_pointer) const noexcept;
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/**
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* Recursive function which processes the json path of each child element
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* Recursive function which processes the JSON path of each child element
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*/
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inline void process_json_path_of_child_elements(std::vector<element>::iterator& current, std::vector<element>::iterator& end, const std::string_view& path_suffix, std::vector<element>& accumulator) const noexcept;
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@@ -189,7 +189,7 @@ public:
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* JSONPath queries that trivially convertible to JSON Pointer queries: key
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* names and array indices.
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*
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* https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
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* https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
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*
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* @return The value associated with the given JSONPath expression, or:
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* - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails
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@@ -107,7 +107,7 @@ public:
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* JSONPath queries that trivially convertible to JSON Pointer queries: key
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* names and array indices.
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*
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* https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
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* https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
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*
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* @return The value associated with the given JSONPath expression, or:
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* - INVALID_JSON_POINTER if the JSONPath to JSON Pointer conversion fails
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@@ -701,7 +701,7 @@ public:
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* JSONPath queries that trivially convertible to JSON Pointer queries: key
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* names and array indices.
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*
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* https://datatracker.ietf.org/doc/html/draft-normington-jsonpath-00
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* https://www.rfc-editor.org/rfc/rfc9535 (RFC 9535)
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*
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* Key values are matched exactly, without unescaping or Unicode normalization.
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* We do a byte-by-byte comparison. E.g.
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