Starting DB implementation.

Added Makefile, id_counter.erl, and yaws.conf.
Created ts_common module. Will contain common DB code. So far only list/3.
Created ts_timeline module. DB code for storing timeline entries.
Created ts_entry module, DB code for storing timelin entries.

Makefile

@@ -0,0 +1,38 @@
+MODS = $(wildcard src/*.erl)
+BEAMS = $(MODS:src/%.erl=ebin/%.beam)
+TEST_MODS = $(wildcard test/*.erl)
+TEST_BEAMS = $(TEST_MODS:test/%.erl=test/%.beam)
+
+all : compile test
+
+compile : $(BEAMS)
+
+compile-test : $(TEST_BEAMS)
+
+test : start-test-server run-test stop-test-server
+
+test-shell : compile compile-test
+	@echo Starting an interactive YAWS shell with test paths loaded.
+	@yaws -i --pa test --id test_inst
+
+run-test : compile compile-test
+	@erl -pa ./ebin -pa ./test -run timestamper_api_tests test -run init stop -noshell
+
+start-test-server :
+	@yaws -D --id test_inst
+
+stop-test-server :
+	@yaws --stop --id test_inst
+
+clean:
+	rm -rf ebin/* erl_crash.dump test/*.beam
+
+init:
+	-mkdir ebin
+
+ebin/%.beam : src/%.erl
+	erlc -W -o ebin $<
+
+test/%.beam : test/%.erl
+	@echo Compiling sources...
+	erlc -W -o test $<

src/id_counter.erl

@@ -0,0 +1,23 @@
+-module(id_counter).
+-export([create_table/1, next_counter/1, dirty_next_counter/1]).
+
+-include("vbs_db_records.hrl").
+
+%% Create the table structure for Mnesia
+create_table(Opts) ->
+    mnesia:create_table(id_counter, Opts ++
+        [{attributes, record_info(fields, id_counter)}]).
+
+%% Get the next id for a given name
+next_counter(Name) ->
+    Rec = case mnesia:read({id_counter, Name}) of
+        [] -> #id_counter{name=Name, next_value=0};
+        [Val] -> Val
+    end,
+    NextRec = Rec#id_counter{next_value = Rec#id_counter.next_value+ 1},
+    ok = mnesia:write(NextRec),
+    Rec#id_counter.next_value.
+
+%% Get the next id for a given name
+dirty_next_counter(Name) ->
+    mnesia:dirty_update_counter(id_counter, Name, 1) - 1.

src/ts_common.erl

@@ -0,0 +1,29 @@
+-module(ts_common).
+-export([list/3]).
+
+-include_lib("stdlib/include/qlc.hrl").
+
+%% list <Length> number of records, skipping the first <Start>
+list(Table, Start, Length)
+when is_atom(Table) and is_integer(Start) and is_integer(Length) ->
+    list(qlc:q([A || A <- mnesia:table(Table)]), Start, Length);
+
+list(Query, Start, Length) ->
+    {atomic, Result} = mnesia:transaction(fun() ->
+        % create a cursor for the query
+        C = qlc:cursor(Query),
+
+        % skip the first Start records
+        if Start > 0 -> qlc:next_answers(C, Start);
+            true -> ok
+        end,
+
+        % return Length records
+        List = qlc:next_answers(C, Length),
+
+        % free cursor
+        ok = qlc:delete_cursor(C),
+
+        List
+    end),
+    Result.

src/ts_db_records.hrl

@@ -0,0 +1,12 @@
+-record(ts_timeline, {
+    ref,    % {username, timelineid}
+    created,% {{year, month, day}, {hour, minute, second}}
+    desc
+}).
+
+-record(ts_entry, {
+    ref,        % {username, timelineid, eventid}
+    timestamp,  % {{year, month, day}, {hour, minute, second}}
+    mark,       % String description of entry
+    notes       % String with further notes about the entry
+}).

src/ts_entry.erl

@@ -0,0 +1,19 @@
+-module(ts_entry).
+-export([create_table/1, new/1, update/1, list/3]).
+
+-include("ts_db_records.hrl").
+-include_lib("stdlib/include/qlc.hrl").
+
+create_table(TableOpts) ->
+    mnesia:create_table(ts_entry,
+        TableOpts ++ [{attributes, record_info(fields, ts_entry)},
+                      {type, ordered_set}, {index, timestamp}]).
+
+new(ER = #ts_entry()) ->
+    {atmoic, NewRow) = mnesia:transaction(fun() ->
+        {Username, TimelineId, _} = ER#ts_entry.ref,
+        NextId = id_counter:next_counter(ts_entry_id),
+        NewRow = ER#ts_entry{ref = {Username, TimelineId, NextId}},
+        ok = mnesia:write(NewRow),
+        NewRow end),
+    {ok, NewRow}.

src/ts_timeline.erl

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+-module(ts_timeline).
+-export([create_table/1, new/1, update/1, list/3]).
+
+-include("ts_db_records.hrl").
+-include_lib("stdlib/include/qlc.hrl").
+
+create_table(TableOpts) ->
+    mnesia:create_table(ts_timeline,
+        TableOpts ++ [{attributes, record_info(fields, ts_timeline)},
+                      {type, ordered_set}]).
+
+new(TR = #ts_timeline{}) ->
+    case mnesia:dirty_read(ts_timeline, TR#ts_timeline.ref) of
+        [ExistingRecord] -> {error, {record_exists, ExistingRecord}};
+        [] -> mnesia:dirty_write(TR)
+    end.
+
+update(TR = #ts_timeline{}) ->
+    
+    % look for the existing record
+    case mnesia:dirty_read(ts_timeline, TR#ts_timeline.ref) of
+        % record does not exist
+        [] -> no_record;
+        % record exists, update
+        [Record] -> mnesia:dirty_write(TR)
+    end.
+
+list(Username, Start, Length) -> 
+    ts_common:list(
+        qlc:q([T || T <- mnesia:table(ts_timeline),
+                    T#ts_timeline.ref = {Username, _}]),
+        Start, Length).
+
+

yaws.conf

@@ -0,0 +1,10 @@
+ebin_dir = /home/jdbernard/projects/timestamper/web-app/ebin
+#include_dir = /home/jdbernard/projects/timestamper/web-app/src
+
+runmod = timestamper
+
+<server timestamper-test>
+    port = 8000
+    listen = /home/jdbernard/projects/timestamper/web-app/www
+    appmods = timestamper_api
+</server>