Merge pull request sparklemotion#390 from sparklemotion/flavorjones-doc-improvements-2023-05

documentation improvements

Author: flavorjones

.gitignore

@@ -8,7 +8,9 @@ test/test.db
 
 Gemfile.lock
 
+doc/
 gems/
+issues/
 pkg/
 ports/
 tmp/

.rdoc_options

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+---
+encoding: UTF-8
+static_path: []
+rdoc_include: []
+page_dir: 
+charset: UTF-8
+exclude:
+- "~\\z"
+- "\\.orig\\z"
+- "\\.rej\\z"
+- "\\.bak\\z"
+- "\\.gemspec\\z"
+- "issues"
+- "bin"
+- "rakelib"
+- "ext/sqlite3/extconf.rb"
+hyperlink_all: false
+line_numbers: false
+locale: 
+locale_dir: locale
+locale_name: 
+main_page: "README.md"
+markup: rdoc
+output_decoration: true
+show_hash: false
+skip_tests: true
+tab_width: 8
+template_stylesheets: []
+title: 
+visibility: :protected
+webcvs: 

faq/faq.md renamed to FAQ.md

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+
+# Installation and Using SQLite3 extensions
+
+This document will help you install the `sqlite3` ruby gem. It also contains instructions on loading database extensions and building against drop-in replacements for sqlite3.
+
+## Installation
+
+### Native Gems (recommended)
+
+In v1.5.0 and later, native (precompiled) gems are available for recent Ruby versions on these platforms:
+
+- `aarch64-linux` (requires: glibc >= 2.29)
+- `arm-linux` (requires: glibc >= 2.29)
+- `arm64-darwin`
+- `x64-mingw32` / `x64-mingw-ucrt`
+- `x86-linux` (requires: glibc >= 2.17)
+- `x86_64-darwin`
+- `x86_64-linux` (requires: glibc >= 2.17)
+
+If you are using one of these Ruby versions on one of these platforms, the native gem is the recommended way to install sqlite3-ruby.
+
+For example, on a linux system running Ruby 3.1:
+
+``` text
+$ ruby -v
+ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
+
+$ time gem install sqlite3
+Fetching sqlite3-1.5.0-x86_64-linux.gem
+Successfully installed sqlite3-1.5.0-x86_64-linux
+1 gem installed
+
+real    0m4.274s
+user    0m0.734s
+sys     0m0.165s
+```
+
+#### Avoiding the precompiled native gem
+
+The maintainers strongly urge you to use a native gem if at all possible. It will be a better experience for you and allow us to focus our efforts on improving functionality rather than diagnosing installation issues.
+
+If you're on a platform that supports a native gem but you want to avoid using it in your project, do one of the following:
+
+- If you're not using Bundler, then run `gem install sqlite3 --platform=ruby`
+- If you are using Bundler
+  - version 2.3.18 or later, you can specify [`gem "sqlite3", force_ruby_platform: true`](https://bundler.io/v2.3/man/gemfile.5.html#FORCE_RUBY_PLATFORM)
+  - version 2.1 or later, then you'll need to run `bundle config set force_ruby_platform true`
+  - version 2.0 or earlier, then you'll need to run `bundle config force_ruby_platform true`
+
+
+### Compiling the source gem
+
+If you are on a platform or version of Ruby that is not covered by the Native Gems, then the vanilla "ruby platform" (non-native) gem will be installed by the `gem install` or `bundle` commands.
+
+
+#### Packaged libsqlite3
+
+By default, as of v1.5.0 of this library, the latest available version of libsqlite3 is packaged with the gem and will be compiled and used automatically. This takes a bit longer than the native gem, but will provide a modern, well-supported version of libsqlite3.
+
+For example, on a linux system running Ruby 2.5:
+
+``` text
+$ ruby -v
+ruby 2.5.9p229 (2021-04-05 revision 67939) [x86_64-linux]
+
+$ time gem install sqlite3
+Building native extensions. This could take a while...
+Successfully installed sqlite3-1.5.0
+1 gem installed
+
+real    0m20.620s
+user    0m23.361s
+sys     0m5.839s
+```
+
+
+#### System libsqlite3
+
+If you would prefer to build the sqlite3-ruby gem against your system libsqlite3, which requires that you install libsqlite3 and its development files yourself, you may do so by using the `--enable-system-libraries` flag at gem install time.
+
+PLEASE NOTE:
+
+- you must avoid installing a precompiled native gem (see [previous section](#avoiding-the-precompiled-native-gem))
+- only versions of libsqlite3 `>= 3.5.0` are supported,
+- and some library features may depend on how your libsqlite3 was compiled.
+
+For example, on a linux system running Ruby 2.5:
+
+``` text
+$ time gem install sqlite3 -- --enable-system-libraries
+Building native extensions with: '--enable-system-libraries'
+This could take a while...
+Successfully installed sqlite3-1.5.0
+1 gem installed
+
+real    0m4.234s
+user    0m3.809s
+sys     0m0.912s
+```
+
+If you're using bundler, you can opt into system libraries like this:
+
+``` sh
+bundle config build.sqlite3 --enable-system-libraries
+```
+
+If you have sqlite3 installed in a non-standard location, you may need to specify the location of the include and lib files by using `--with-sqlite-include` and `--with-sqlite-lib` options (or a `--with-sqlite-dir` option, see [MakeMakefile#dir_config](https://ruby-doc.org/stdlib-3.1.1/libdoc/mkmf/rdoc/MakeMakefile.html#method-i-dir_config)). If you have pkg-config installed and configured properly, this may not be necessary.
+
+``` sh
+gem install sqlite3 -- \
+  --enable-system-libraries \
+  --with-sqlite3-include=/opt/local/include \
+  --with-sqlite3-lib=/opt/local/lib
+```
+
+
+#### System libsqlcipher
+
+If you'd like to link against a system-installed libsqlcipher, you may do so by using the `--with-sqlcipher` flag:
+
+``` text
+$ time gem install sqlite3 -- --with-sqlcipher
+Building native extensions with: '--with-sqlcipher'
+This could take a while...
+Successfully installed sqlite3-1.5.0
+1 gem installed
+
+real    0m4.772s
+user    0m3.906s
+sys     0m0.896s
+```
+
+If you have sqlcipher installed in a non-standard location, you may need to specify the location of the include and lib files by using `--with-sqlite-include` and `--with-sqlite-lib` options (or a `--with-sqlite-dir` option, see [MakeMakefile#dir_config](https://ruby-doc.org/stdlib-3.1.1/libdoc/mkmf/rdoc/MakeMakefile.html#method-i-dir_config)). If you have pkg-config installed and configured properly, this may not be necessary.
+
+
+## Using SQLite3 extensions
+
+### How do I load a sqlite extension?
+
+Some add-ons are available to sqlite as "extensions". The instructions that upstream sqlite provides at https://www.sqlite.org/loadext.html are the canonical source of advice, but here's a brief example showing how you can do this with the `sqlite3` ruby gem.
+
+In this example, I'll be loading the ["spellfix" extension](https://www.sqlite.org/spellfix1.html):
+
+``` text
+# download spellfix.c from somewherehttp://www.sqlite.org/src/finfo?name=ext/misc/spellfix.c
+$ wget https://raw.githubusercontent.com/sqlite/sqlite/master/ext/misc/spellfix.c
+spellfix.c                     100%[=================================================>] 100.89K  --.-KB/s    in 0.09s
+
+# follow instructions at https://www.sqlite.org/loadext.html
+# (you will need sqlite3 development packages for this)
+$ gcc -g -fPIC -shared spellfix.c -o spellfix.o
+
+$ ls -lt
+total 192
+-rwxrwxr-x 1 flavorjones flavorjones  87984 2023-05-24 10:44 spellfix.o
+-rw-rw-r-- 1 flavorjones flavorjones 103310 2023-05-24 10:43 spellfix.c
+```
+
+Then, in your application, use that `spellfix.o` file like this:
+
+``` ruby
+require "sqlite3"
+
+db = SQLite3::Database.new(':memory:')
+db.enable_load_extension(true)
+db.load_extension("/path/to/sqlite/spellfix.o")
+db.execute("CREATE VIRTUAL TABLE demo USING spellfix1;")
+```
+
+### How do I use an alternative sqlite3 implementation?
+
+Some packages, like pSQLite Encryption Extension ("SEE"), are intended to be ABI-compatible drop-in replacements for the sqlite3 shared object.
+
+If you've installed your alternative as an autotools-style installation, the directory structure will look like this:
+
+```
+/opt/see
+├── bin
+│   └── sqlite3
+├── include
+│   ├── sqlite3.h
+│   └── sqlite3ext.h
+├── lib
+│   ├── libsqlite3.a
+│   ├── libsqlite3.la
+│   ├── libsqlite3.so -> libsqlite3.so.0.8.6
+│   ├── libsqlite3.so.0 -> libsqlite3.so.0.8.6
+│   ├── libsqlite3.so.0.8.6
+│   └── pkgconfig
+│       └── sqlite3.pc
+└── share
+    └── man
+        └── man1
+            └── sqlite3.1
+```
+
+You can build this gem against that library like this:
+
+```
+gem install sqlite3 --platform=ruby -- \
+  --enable-system-libraries \
+  --with-opt-dir=/opt/see
+```
+
+Explanation:
+
+- use `--platform=ruby` to avoid the precompiled native gems (see the README)
+- the `--` separates arguments passed to "gem install" from arguments passed to the C extension builder
+- use `--enable-system-libraries` to avoid the vendored sqlite3 source
+- use `--with-opt-dir=/path/to/installation` to point the build process at the desired header files and shared object files
+
+Alternatively, if you've simply downloaded an "amalgamation" and so your compiled library and header files are in arbitrary locations, try this more detailed command:
+
+```
+gem install sqlite3 --platform=ruby -- \
+  --enable-system-libraries \
+  --with-opt-include=/path/to/include \
+  --with-opt-lib=/path/to/lib
+```
+