Change Details

This is motivated by D63591, where we realized that there isn't a really good way of telling whether a DataExtractor is reading actual data, or is it just returning default values because it reached the end of the buffer. This (WIP) patch tries to solve this issue by providing a kind of a streaming api on top of the data extractor. It is inspired by the std::iostreams api, where one can also blindly read from a stream (receiving default values in case of errors), and then check for any erros in bulk once the parse has finished. To achieve this, I introduce a new class (DataStream), which encapsulates three things: - the DataExtractor we are reading from - the current position within that extractor - an error flag Please let me know what you think.

This is motivated by D63591, where we realized that there isn't a really good way of telling whether a DataExtractor is reading actual data, or is it just returning default values because it reached the end of the buffer. This patch resolves that by providing a new "Cursor" class. A Cursor object encapsulates two things: - the current position/offset in the DataExtractor - an error object Storing the error object inside the Cursor enables one to use the same pattern as the std::{io}stream API, where one can blindly perform a sequence of reads and only check for errors once at the end of the operation. Similarly to the stream API, as soon as we encounter one error, all of the subsequent operations are skipped (return default values) too, even if the would suceed with clear error state. Unlike the std::stream API (but in line with other llvm APIs), we force the error state to be checked through usage of llvm::Error.

This is motivated by D63591, where we realized that there isn't a really good way of telling whether a DataExtractor is reading actual data, or is it just returning default values because it reached the end of the buffer. This (WIP) patch tries to resolve this issues that by providing a kind of anew "Cursor" class. A Cursor streaming api on top of the data extractor. It is inspired by theobject encapsulates two things: std::iostreams api, where one can also blindly read from a stream- the current position/offset in the DataExtractor (receiving default values in case of errors), and then check for any erros in bulk once the parse has finished.- an error object To achieve this, I introduce a new class (DataStream), whichStoring the error object inside the Cursor enables one to use the same encapsulates three things:pattern as the std::{io}stream API, where one can blindly perform a - the DataExtractor we are reading fromsequence of reads and only check for errors once at the end of the - the current position within that extractoroperation. Similarly to the stream API, as soon as we encounter one error, all of the subsequent operations are skipped (return default values) too, even if the would suceed with clear error state. Unlike the std::stream API (but in line with other llvm APIs), we force the error state to be checked through usage of llvm::Error. - an error flag Please let me know what you think.