Add json_document and json_view: parse, accept, types, materialize

The public classes of the zero-copy view (#5295), in the new header
<nlohmann/json_view.hpp>:

- basic_json_document<BasicJsonType>: parse (borrowing contiguous byte
  inputs, owning rvalue strings, streams, and other inputs), parse_copy,
  accept, read, root, is_discarded, source, owns_source, node_count,
  memory_usage, shrink_to_fit
- basic_json_view<BasicJsonType>: type and the is_* queries, size, empty,
  materialize (the value parse() would produce, built by the same SAX
  handler), source_offset
- the aliases json_document, json_view, ordered_json_document, and
  ordered_json_view

A parse error throws the exception basic_json::parse would throw for the
same input: the library parser is run on the failing input, so messages,
positions, and exception ids are the same. Inputs of 4 GiB or more are
rejected with out_of_range.416.

The single header single_include/nlohmann/json_view.hpp keeps including
json.hpp; make amalgamate, check-amalgamation, include.zip, and release
handle it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-30 20:57:43 +02:00
parent e96e2982a5
commit cf352d4ef5
10 changed files with 3623 additions and 6 deletions
+16 -6
View File
@@ -23,6 +23,7 @@ AMALGAMATED_FILE=single_include/nlohmann/json.hpp
AMALGAMATED_FWD_FILE=single_include/nlohmann/json_fwd.hpp
# json_literals.hpp only includes <nlohmann/json.hpp>, so it is copied verbatim
AMALGAMATED_LITERALS_FILE=single_include/nlohmann/json_literals.hpp
AMALGAMATED_VIEW_FILE=single_include/nlohmann/json_view.hpp
##########################################################################
@@ -31,7 +32,7 @@ AMALGAMATED_LITERALS_FILE=single_include/nlohmann/json_literals.hpp
# main target
all:
@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd,_literals}.hpp from the include/nlohmann sources"
@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd,_literals,_view}.hpp from the include/nlohmann sources"
@echo "BUILD.bazel - regenerate the Bazel BUILD file from the include/nlohmann sources"
@echo "ChangeLog.md - generate ChangeLog file"
@echo "check-amalgamation - check whether sources have been amalgamated and BUILD.bazel is up to date"
@@ -156,14 +157,14 @@ install_astyle:
# call the Artistic Style pretty printer on all source files
pretty: install_astyle
$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) docs/mkdocs/docs/examples/*.cpp
$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE) docs/mkdocs/docs/examples/*.cpp
# call the Clang-Format on all source files
pretty_format:
for FILE in $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) docs/mkdocs/docs/examples/*.cpp; do echo $$FILE; clang-format -i $$FILE; done
# create single header files and pretty print
amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE)
amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE)
$(MAKE) pretty
# call the amalgamation tool for json.hpp
@@ -178,19 +179,26 @@ $(AMALGAMATED_FWD_FILE): $(SRCS)
$(AMALGAMATED_LITERALS_FILE): include/nlohmann/json_literals.hpp
cp include/nlohmann/json_literals.hpp $(AMALGAMATED_LITERALS_FILE)
# call the amalgamation tool for json_view.hpp (keeps including json.hpp)
$(AMALGAMATED_VIEW_FILE): $(SRCS)
tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_view.json -s . --verbose=yes
# check if file single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
# Note: this target is called by Travis
check-amalgamation:
@mv $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~
@mv $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~
@mv $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_LITERALS_FILE)~
@mv $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~
@$(MAKE) amalgamate
@diff $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE) ; false)
@diff $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE) ; false)
@diff $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_LITERALS_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_LITERALS_FILE)~ $(AMALGAMATED_LITERALS_FILE) ; false)
@diff $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE) ; false)
@mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE)
@mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE)
@mv $(AMALGAMATED_LITERALS_FILE)~ $(AMALGAMATED_LITERALS_FILE)
@mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE)
@mv BUILD.bazel BUILD.bazel~
@$(MAKE) BUILD.bazel
@diff BUILD.bazel BUILD.bazel~ || (echo "===================================================================\n BUILD.bazel is out of date! Please run 'make BUILD.bazel'.\n===================================================================" ; mv BUILD.bazel~ BUILD.bazel ; false)
@@ -231,7 +239,7 @@ json.tar.xz:
# We use `-X` to make the resulting ZIP file reproducible, see
# <https://content.pivotal.io/blog/barriers-to-deterministic-reproducible-zip-files>.
include.zip: BUILD.bazel
zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
# Create the files for a release and add signatures and hashes.
release: include.zip json.tar.xz
@@ -241,12 +249,14 @@ release: include.zip json.tar.xz
gpg --armor --detach-sig $(AMALGAMATED_FILE)
gpg --armor --detach-sig $(AMALGAMATED_FWD_FILE)
gpg --armor --detach-sig $(AMALGAMATED_LITERALS_FILE)
gpg --armor --detach-sig $(AMALGAMATED_VIEW_FILE)
gpg --armor --detach-sig json.tar.xz
cp $(AMALGAMATED_FILE) release_files
cp $(AMALGAMATED_FWD_FILE) release_files
cp $(AMALGAMATED_LITERALS_FILE) release_files
mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc $(AMALGAMATED_LITERALS_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
cd release_files ; shasum -a 256 json.hpp include.zip json.tar.xz > hashes.txt
cp $(AMALGAMATED_VIEW_FILE) release_files
mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc $(AMALGAMATED_LITERALS_FILE).asc $(AMALGAMATED_VIEW_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
cd release_files ; shasum -a 256 json.hpp json_view.hpp include.zip json.tar.xz > hashes.txt
##########################################################################