backups (tgz): save integrity information

we generate a signing key pair for each target. Initially, I had this
as global. We needed a route to return the public key and putting it
under backup target seemed natural. Since we delete the backups when
we delete a target, we lose all the signing hashes. So, it's fine to lose
the key pair on target delete.

src/backups.js

@@ -8,6 +8,7 @@ exports = module.exports = {
     add,
     update,
     setState,
+    setIntegrity,
     list,
     del,
 
@@ -29,7 +30,7 @@ const assert = require('assert'),
     hat = require('./hat.js'),
     safe = require('safetydance');
 
-const BACKUPS_FIELDS = [ 'id', 'remotePath', 'label', 'identifier', 'creationTime', 'packageVersion', 'type', 'dependsOnJson', 'state', 'manifestJson', 'preserveSecs', 'encryptionVersion', 'appConfigJson', 'targetId' ].join(',');
+const BACKUPS_FIELDS = [ 'id', 'remotePath', 'label', 'identifier', 'creationTime', 'packageVersion', 'type', 'integrityJson', 'dependsOnJson', 'state', 'manifestJson', 'preserveSecs', 'encryptionVersion', 'appConfigJson', 'targetId' ].join(',');
 
 function postProcess(result) {
     assert.strictEqual(typeof result, 'object');
@@ -40,6 +41,9 @@ function postProcess(result) {
     result.manifest = result.manifestJson ? safe.JSON.parse(result.manifestJson) : null;
     delete result.manifestJson;
 
+    result.integrity = result.integrityJson ? safe.JSON.parse(result.integrityJson) : null;
+    delete result.integrityJson;
+
     result.appConfig = result.appConfigJson ? safe.JSON.parse(result.appConfigJson) : null;
     delete result.appConfigJson;
 
@@ -166,6 +170,14 @@ async function setState(id, state) {
     if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Backup not found');
 }
 
+async function setIntegrity(id, integrity) {
+    assert.strictEqual(typeof id, 'string');
+    assert.strictEqual(typeof integrity, 'object');
+
+    const result = await database.query('UPDATE backups SET integrityJson = ? WHERE id = ?', [JSON.stringify(integrity), id]);
+    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Backup not found');
+}
+
 async function list(page, perPage) {
     assert(typeof page === 'number' && page > 0);
     assert(typeof perPage === 'number' && perPage > 0);