workflow: Account for job postings correctly and fix existing issues

Without removing postings correctly, it was possible to end up with
multiple workers assigned to a job that workflow had suspended
multiple times, which caused crashes if more than one worker was
assigned to the same job by DF.

This adds an additional command, fix-job-postings, that runs
automatically when loading a world and fixes:
- Multiple job postings that point to the same job
- Job postings that point to a job where posting_index == -1
  (i.e. jobs that should have no posting assigned)

Fixes #741

library/LuaApi.cpp

@@ -1464,6 +1464,7 @@ static const LuaWrapper::FunctionReg dfhack_job_module[] = {
     WRAPM(Job,isSuitableMaterial),
     WRAPM(Job,getName),
     WRAPM(Job,linkIntoWorld),
+    WRAPM(Job,removePostings),
     WRAPN(is_equal, jobEqual),
     WRAPN(is_item_equal, jobItemEqual),
     { NULL, NULL }

library/include/modules/Job.h

@@ -72,6 +72,11 @@ namespace DFHack
 
         DFHACK_EXPORT bool linkIntoWorld(df::job *job, bool new_id = true);
 
+        // Flag this job's posting as "dead" and set its posting_index to -1
+        // If remove_all is true, flag all postings pointing to this job
+        // Returns true if any postings were removed
+        DFHACK_EXPORT bool removePostings(df::job *job, bool remove_all = false);
+
         // lists jobs with ids >= *id_var, and sets *id_var = *job_next_id;
         DFHACK_EXPORT bool listNewlyCreated(std::vector<df::job*> *pvec, int *id_var);
 

library/modules/Job.cpp

@@ -377,6 +377,34 @@ bool DFHack::Job::linkIntoWorld(df::job *job, bool new_id)
     }
 }
 
+bool DFHack::Job::removePostings(df::job *job, bool remove_all)
+{
+    using df::global::world;
+    CHECK_NULL_POINTER(job);
+    bool removed = false;
+    if (!remove_all)
+    {
+        if (job->posting_index >= 0 && job->posting_index < world->job_postings.size())
+        {
+            world->job_postings[job->posting_index]->flags.bits.dead = true;
+            removed = true;
+        }
+    }
+    else
+    {
+        for (auto it = world->job_postings.begin(); it != world->job_postings.end(); ++it)
+        {
+            if ((**it).job == job)
+            {
+                (**it).flags.bits.dead = true;
+                removed = true;
+            }
+        }
+    }
+    job->posting_index = -1;
+    return removed;
+}
+
 bool DFHack::Job::listNewlyCreated(std::vector<df::job*> *pvec, int *id_var)
 {
     using df::global::world;

library/xml

@@ -1 +1 @@
-Subproject commit 378a580f7e333607a64a301d598e3885954a5d9d
+Subproject commit bb950d99da543f314f3dd9babf1446c8331ff99d

plugins/workflow.cpp

@@ -59,10 +59,13 @@ REQUIRE_GLOBAL(job_next_id);
 /* Plugin registration */
 
 static command_result workflow_cmd(color_ostream &out, vector <string> & parameters);
+static command_result fix_job_postings_cmd(color_ostream &out, vector<string> &parameters);
 
 static void init_state(color_ostream &out);
 static void cleanup_state(color_ostream &out);
 
+static int fix_job_postings(color_ostream *out = NULL, bool dry_run = false);
+
 DFhackCExport command_result plugin_init (color_ostream &out, std::vector <PluginCommand> &commands)
 {
     if (!world || !ui)
@@ -142,6 +145,13 @@ DFhackCExport command_result plugin_init (color_ostream &out, std::vector <Plugi
                 "    Maintain 10-100 locally-made crafts of exceptional quality.\n"
             )
         );
+        commands.push_back(PluginCommand(
+            "fix-job-postings",
+            "Fix broken job postings caused by certain versions of workflow",
+            fix_job_postings_cmd, false,
+            "fix-job-postings: Fix job postings\n"
+            "fix-job-postings dry|[any argument]: Dry run only (avoid making changes)\n"
+        ));
     }
 
     init_state(out);
@@ -162,6 +172,9 @@ DFhackCExport command_result plugin_onstatechange(color_ostream &out, state_chan
     case SC_MAP_LOADED:
         cleanup_state(out);
         init_state(out);
+        out << "workflow: checking for existing job issues" << endl;
+        if (fix_job_postings(&out))
+            out << "workflow: fixed job issues" << endl;
         break;
     case SC_MAP_UNLOADED:
         cleanup_state(out);
@@ -173,6 +186,14 @@ DFhackCExport command_result plugin_onstatechange(color_ostream &out, state_chan
     return CR_OK;
 }
 
+command_result fix_job_postings_cmd(color_ostream &out, vector<string> &parameters)
+{
+    bool dry = parameters.size();
+    int fixed = fix_job_postings(&out, dry);
+    out << fixed << " job issue(s) " << (dry ? "detected but not fixed" : "fixed") << endl;
+    return CR_OK;
+}
+
 /******************************
  * JOB STATE TRACKING STRUCTS *
  ******************************/
@@ -274,7 +295,7 @@ public:
         {
             if (world->frame_counter >= resume_time && actual_job->flags.bits.suspend)
             {
-                actual_job->unk_v4020_1 = -1;
+                Job::removePostings(actual_job, true);
                 actual_job->flags.bits.suspend = false;
             }
         }
@@ -287,7 +308,7 @@ public:
             if (!actual_job->flags.bits.suspend)
             {
                 actual_job->flags.bits.suspend = true;
-                actual_job->unk_v4020_1 = -1;
+                Job::removePostings(actual_job, true);
             }
         }
 
@@ -406,6 +427,41 @@ public:
     }
 };
 
+static int fix_job_postings (color_ostream *out, bool dry_run)
+{
+    int count = 0;
+    df::job_list_link *link = &world->job_list;
+    while (link)
+    {
+        df::job *job = link->item;
+        if (job)
+        {
+            bool needs_posting = (job->posting_index >= 0);
+            bool found_posting = false;
+            for (auto it = world->job_postings.begin(); it != world->job_postings.end(); ++it)
+            {
+                df::world::T_job_postings *posting = *it;
+                if (posting->job == job && !posting->flags.bits.dead)
+                {
+                    if (!found_posting && needs_posting)
+                        found_posting = true;
+                    else
+                    {
+                        ++count;
+                        if (*out)
+                            *out << "Found extra job posting: Job " << job->id << ": "
+                                << Job::getName(job) << endl;
+                        if (!dry_run)
+                            posting->flags.bits.dead = true;
+                    }
+                }
+            }
+        }
+        link = link->next;
+    }
+    return count;
+}
+
 /******************************
  *      GLOBAL VARIABLES      *
  ******************************/
@@ -1603,6 +1659,12 @@ static int getCountHistory(lua_State *L)
     return 1;
 }
 
+static int fixJobPostings(lua_State *L)
+{
+    bool dry = lua_toboolean(L, 1);
+    lua_pushinteger(L, fix_job_postings(NULL, dry));
+    return 1;
+}
 
 DFHACK_PLUGIN_LUA_FUNCTIONS {
     DFHACK_LUA_FUNCTION(deleteConstraint),
@@ -1614,6 +1676,7 @@ DFHACK_PLUGIN_LUA_COMMANDS {
     DFHACK_LUA_COMMAND(findConstraint),
     DFHACK_LUA_COMMAND(setConstraint),
     DFHACK_LUA_COMMAND(getCountHistory),
+    DFHACK_LUA_COMMAND(fixJobPostings),
     DFHACK_LUA_END
 };