Add support for custom git search path

This commit adds a way to configure, per table, the git search path that
is sometimes required when running the FDW in very specific situations.

Some logic got simplified in how get options too.

This closes #10.

Author: franckverrot

Changelog

@@ -11,6 +11,7 @@
 * Add support for lines added/deleted/files changed
 * Add support for bare repositories
 * Add support for libgit2 up to v0.27
+* Add support for a custom git search path
 
 # Release 1.0.0
 

README.md

@@ -95,10 +95,13 @@ There are no options that can be passed to a git\_fdw server.
 
 ### Foreign Table
 
-The possible options are:
+One must configure the foreign tables appropriately.
 
-* `path`: The path of the git repository;
-* `branch`: The branch to be used.
+Here are the options:
+
+  * (Required) `path`: The path of the git repository;
+  * (Required) `branch`: The branch to be used;
+  * (Optional) `git_search_path`: Sometimes libgit2 has to be told where to find your configuration. See #10 for details.
 
 ## Note on Patches/Pull Requests
 

execution_state.h

@@ -2,6 +2,7 @@ typedef struct GitFdwExecutionState
 {
 	char	   *path;
 	char	   *branch;
+	char	   *git_search_path;
 	List	   *options;
 	git_repository *repo;
 	int passes;

git_fdw.c

@@ -82,6 +82,7 @@ Datum git_fdw_validator(PG_FUNCTION_ARGS) {
   Oid      catalog = PG_GETARG_OID(1);
   char     *path   = NULL;
   char     *branch = NULL;
+  char     *git_search_path = NULL;
   List     *other_options = NIL;
   ListCell   *cell;
 
@@ -105,7 +106,7 @@ Datum git_fdw_validator(PG_FUNCTION_ARGS) {
               opt->optname);
       }
 
-      ereport(ERROR,
+      ereport(WARNING,
           (errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
            errmsg("invalid option \"%s\"", def->defname),
            buf.len > 0
@@ -130,6 +131,14 @@ Datum git_fdw_validator(PG_FUNCTION_ARGS) {
              errmsg("conflicting or redundant options")));
       branch = defGetString(def);
     }
+    else if (strcmp(def->defname, "git_search_path") == 0)
+    {
+      if (git_search_path)
+        ereport(ERROR,
+            (errcode(ERRCODE_SYNTAX_ERROR),
+             errmsg("conflicting or redundant options")));
+      git_search_path = defGetString(def);
+    }
     else
       other_options = lappend(other_options, def);
   }
@@ -145,6 +154,7 @@ Datum git_fdw_validator(PG_FUNCTION_ARGS) {
 // TODO:  Find where this variable should go (Plan or Path?)
 char * repository_path;
 char * repository_branch;
+char * repository_git_search_path;
 
 static bool is_valid_option(const char *option, Oid context) {
   const struct GitFdwOption *opt;
@@ -160,29 +170,27 @@ static bool is_valid_option(const char *option, Oid context) {
 static void gitGetOptions(Oid foreigntableid, GitFdwPlanState *state, List **other_options) {
   ForeignTable *table;
   List     *options;
-  ListCell   *lc,
-             *prev;
+  ListCell   *lc;
 
   table = GetForeignTable(foreigntableid);
 
   options = NIL;
   options = list_concat(options, table->options);
 
-  prev = NULL;
   foreach(lc, options) {
     DefElem *def = (DefElem *) lfirst(lc);
 
     if (strcmp(def->defname, "path") == 0) {
       state->path = defGetString(def);
-      options = list_delete_cell(options, lc, prev);
     }
 
     if (strcmp(def->defname, "branch") == 0) {
       state->branch = defGetString(def);
-      options = list_delete_cell(options, lc, prev);
     }
 
-    prev = lc;
+    if (strcmp(def->defname, "git_search_path") == 0) {
+      state->git_search_path = defGetString(def);
+    }
   }
 
   if (state->path == NULL) {
@@ -260,8 +268,9 @@ static ForeignScan * gitGetForeignPlan(PlannerInfo *root, RelOptInfo *baserel, O
 #endif
       ); // Assuming outer_plan is null
 
-  repository_path   = ((GitFdwPlanState*)scan->fdw_private)->path;
-  repository_branch = ((GitFdwPlanState*)scan->fdw_private)->branch;
+  repository_path            = ((GitFdwPlanState*)scan->fdw_private)->path;
+  repository_branch          = ((GitFdwPlanState*)scan->fdw_private)->branch;
+  repository_git_search_path = ((GitFdwPlanState*)scan->fdw_private)->git_search_path;
   return scan;
 }
 
@@ -280,13 +289,22 @@ static void gitBeginForeignScan(ForeignScanState *node, int eflags) {
   git_libgit2_init();
 
   festate = (GitFdwExecutionState *) palloc(sizeof(GitFdwExecutionState));
-  festate->path   = repository_path;
-  festate->branch = repository_branch;
-  festate->repo   = NULL;
-  festate->walker = NULL;
+  festate->path            = repository_path;
+  festate->branch          = repository_branch;
+  festate->git_search_path = repository_git_search_path;
+  festate->repo            = NULL;
+  festate->walker          = NULL;
 
   node->fdw_state = (void *) festate;
 
+  if(festate->git_search_path != NULL){
+    git_libgit2_opts(
+        GIT_OPT_SET_SEARCH_PATH,
+        GIT_CONFIG_LEVEL_GLOBAL,
+        festate->git_search_path
+        );
+  }
+
   if(festate->repo == NULL) {
     int repo_opened = -1;
     if((repo_opened = git_repository_open(&festate->repo, festate->path)) != GIT_OK){

options.h

@@ -7,5 +7,6 @@ struct GitFdwOption {
 static const struct GitFdwOption valid_options[] = {
 	{"path",   ForeignTableRelationId},
 	{"branch", ForeignTableRelationId},
+	{"git_search_path", ForeignTableRelationId},
 	{NULL,     InvalidOid}
 };

plan_state.h

@@ -2,6 +2,7 @@ typedef struct GitFdwPlanState
 {
 	char	   *path;
 	char	   *branch;
+	char	   *git_search_path;
 	List	   *options;
 	BlockNumber pages;
 	double	    ntuples;

tests/setup.sql

@@ -15,5 +15,6 @@ CREATE FOREIGN TABLE
 SERVER git_fdw_server
 OPTIONS (
   path '/git_fdw/repo.git',
-  branch 'refs/heads/master'
+  branch 'refs/heads/master',
+  git_search_path '/optional/custom/search_path'
 );