From b024ca101ec0c274595407158edad945bec7868d Mon Sep 17 00:00:00 2001
From: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Date: Fri, 5 Apr 2019 21:33:27 +0200
Subject: [PATCH] Dive site: make UUID generation deterministic

Instead of using a random UUID, use an SHA1 hash of name, description
and notes (if defined). This is necessary for testing.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
---
 core/divesite.c              | 26 ++++++++++++++++++++------
 dives/TestDiveDivelogsDE.xml |  4 ++--
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/core/divesite.c b/core/divesite.c
index 8757aeed7..85ce8da37 100644
--- a/core/divesite.c
+++ b/core/divesite.c
@@ -6,6 +6,7 @@
 #include "divelist.h"
 #include "membuffer.h"
 #include "table.h"
+#include "sha1.h"
 
 #include <math.h>
 
@@ -129,14 +130,27 @@ static MAKE_REMOVE(dive_site_table, struct dive_site *, dive_site)
 
 int add_dive_site_to_table(struct dive_site *ds, struct dive_site_table *ds_table)
 {
+	/* If the site doesn't yet have an UUID, create a new one.
+	 * Make this deterministic for testing. */
+	if (!ds->uuid) {
+		SHA_CTX ctx;
+		uint32_t csum[5];
+
+		SHA1_Init(&ctx);
+		if (ds->name)
+			SHA1_Update(&ctx, ds->name, strlen(ds->name));
+		if (ds->description)
+			SHA1_Update(&ctx, ds->description, strlen(ds->description));
+		if (ds->notes)
+			SHA1_Update(&ctx, ds->notes, strlen(ds->notes));
+		SHA1_Final((unsigned char *)csum, &ctx);
+		ds->uuid = csum[0];
+	}
+
 	/* Take care to never have the same uuid twice. This could happen on
 	 * reimport of a log where the dive sites have diverged */
-	while (ds->uuid == 0 || get_dive_site_by_uuid(ds->uuid, ds_table) != NULL) {
-		ds->uuid = rand() & 0xff;
-		ds->uuid |= (rand() & 0xff) << 8;
-		ds->uuid |= (rand() & 0xff) << 16;
-		ds->uuid |= (rand() & 0xff) << 24;
-	}
+	while (ds->uuid == 0 || get_dive_site_by_uuid(ds->uuid, ds_table) != NULL)
+		++ds->uuid;
 
 	int idx = dive_site_table_get_insertion_index(ds_table, ds);
 	add_to_dive_site_table(ds_table, idx, ds);
diff --git a/dives/TestDiveDivelogsDE.xml b/dives/TestDiveDivelogsDE.xml
index 38045119d..fe56f858f 100644
--- a/dives/TestDiveDivelogsDE.xml
+++ b/dives/TestDiveDivelogsDE.xml
@@ -4,11 +4,11 @@
 <divecomputerid model='Vyper Air' deviceid='ffffffff' serial='20400612'/>
 </settings>
 <divesites>
-<site uuid='8c1836f0' name='USA, Hoodsport, WA / Sund Rock' gps='47.400269 -123.142632'>
+<site uuid='64785a00' name='USA, Hoodsport, WA / Sund Rock' gps='47.400269 -123.142632'>
 </site>
 </divesites>
 <dives>
-<dive number='1' divesiteid='8c1836f0' date='2011-05-17' time='11:01:00' duration='32:00 min'>
+<dive number='1' divesiteid='64785a00' date='2011-05-17' time='11:01:00' duration='32:00 min'>
   <buddy>Linus</buddy>
   <notes>Second deep dive
 Linus and I planned and executed - Alex just watching