fix #1032: add constants for file open

[gms1]

This PR only propagates some missing constants for file open to JavaScript:

please see #1032 for a description of possible use cases

Flags For File Open Operations

[kewde]

Looks good, thanks!
Seems like a CI failure, I'll restart it.

[kewde]

I've added a sample test for the shared database, to test a small aspect of it. Ideally we'd have more testing of the shared database but it seems like a more niche feature. On the other hand, I haven't seen tests specifically aimed at read-only databases either.

[kewde]

@gms1 could you shine some light as to why the database creation is failing in the test I added? That seems to be the default way to open databases of different modes without the URI protocol.

[gms1]

@kewde
many thanks!
something like that should work:

db = new sqlite3.Database('file:sqlite3orm',sqlite3.OPEN_SHAREDCACHE|sqlite3.SQLITE_OPEN_MEMORY,done);

or if compiled using SQLITE_USE_URI=1, or in combination with sqlite3.SQLITE_OPEN_URI, we can also use:

'file:sqlite3orm?mode=memory&cache=shared'

quoting from https://www.sqlite.org/inmemorydb.html
In-memory databases are allowed to use shared cache if they are opened using a URI filename. If the unadorned ":memory:" name is used to specify the in-memory database, then that database always has a private cache and is this only visible to the database connection that originally opened it.

[gms1]

please review the added/modified tests

[gms1]

hm all tests are passing during the first run at least, but only on linux, the "shared memory database" tests are failing during the second run: "SQLITE_ERROR: no such access mode: memory"
whats the difference between these two?

running these tests on my linux box works fine:

gms@orion:~/work/HOT/node-sqlite3 (add-open-flags)$ rm -rf node_modules/
gms@orion:~/work/HOT/node-sqlite3 (add-open-flags)$ npm install --build-from-source --sqlite=/usr --clang=1 &>/dev/null
gms@orion:~/work/HOT/node-sqlite3 (add-open-flags)$ npm run test &>/dev/null
gms@orion:~/work/HOT/node-sqlite3 (add-open-flags)$ echo $?
0

[kewde]

The test pass for the SQLite3 package that has been bundled with the application.

Distributor ID:	Ubuntu
Description:	Ubuntu 12.04.5 LTS
Release:	12.04
Codename:	precise

The version in which it is supported is:
https://www.sqlite.org/changes.html#version_3_7_13

The external library for Ubuntu 12.04.5 LTS does not support it.
It has reached it's end of life support. Perhaps it's possible to only execute this test against a version sqlite3 that has the option? I prefer compiling the node-sqlite3 library on older versions of Linux so it has no library (libc, ...) compatibility issues.

[kewde]

@gms1
I think we can get the version of SQLite3 using select sqlite_version(); and then only run the test if the version supports it.

[gms1]

@kewde
please review

[kewde]

Thank you for the contribution @gms1!