make it possible to control the initial NGF size

src/runtime/c/pgf/db.cxx

@@ -134,9 +134,16 @@ struct PGF_INTERNAL_DECL malloc_state
     revision_entry revisions[];
 };
 
+static inline ssize_t get_mmap_size(size_t init_size, size_t page_size)
+{
+    size_t mmap_size = ((init_size+page_size-1)/page_size)*page_size;
+    if (mmap_size < page_size*2)
+        mmap_size = page_size*2;
+    return mmap_size;
+}
 
 PGF_INTERNAL
-PgfDB::PgfDB(const char* filepath, int flags, int mode) {
+PgfDB::PgfDB(const char* filepath, int flags, int mode, size_t init_size) {
     bool is_new = false;
 
     fd = -1;
@@ -147,7 +154,7 @@ PgfDB::PgfDB(const char* filepath, int flags, int mode) {
 
     if (filepath == NULL) {
         this->filepath = NULL;
-        mmap_size = page_size*2;
+        mmap_size = get_mmap_size(init_size, page_size);
         is_new    = true;
     } else {
         fd = open(filepath, flags, mode);
@@ -163,7 +170,7 @@ PgfDB::PgfDB(const char* filepath, int flags, int mode) {
 
         is_new = false;
         if (mmap_size == 0) {
-            mmap_size = page_size*2;
+            mmap_size = get_mmap_size(init_size, page_size);
             if (ftruncate(fd, mmap_size) < 0) {
                 int code = errno;
                 close(fd);

src/runtime/c/pgf/db.h

@@ -101,7 +101,7 @@ public:
     // When the count is zero we release the database.
     size_t ref_count;
 
-    PGF_INTERNAL_DECL PgfDB(const char* filepath, int flags, int mode);
+    PGF_INTERNAL_DECL PgfDB(const char* filepath, int flags, int mode, size_t init_size);
     PGF_INTERNAL_DECL ~PgfDB();
 
     PGF_INTERNAL_DECL static txn_t get_txn_id();

src/runtime/c/pgf/pgf.cxx

@@ -46,12 +46,16 @@ PgfDB *pgf_read_pgf(const char* fpath, PgfRevision *revision,
     FILE *in = NULL;
 
     PGF_API_BEGIN {
-        db = new PgfDB(NULL, 0, 0);
         in = fopen(fpath, "rb");
         if (!in) {
             throw pgf_systemerror(errno, fpath);
         }
 
+        fseek(in, 0, SEEK_END);
+        size_t pgf_size = ftell(in);
+        fseek(in, 0, SEEK_SET);
+        db = new PgfDB(NULL, 0, 0, pgf_size*7);
+
         {
             DB_scope scope(db, WRITER_SCOPE);
 
@@ -71,12 +75,12 @@ PgfDB *pgf_read_pgf(const char* fpath, PgfRevision *revision,
         return db;
     } PGF_API_END
 
-    if (in != NULL)
-        fclose(in);
-
     if (db != NULL)
         delete db;
 
+    if (in != NULL)
+        fclose(in);
+
     return NULL;
 }
 
@@ -90,19 +94,23 @@ PgfDB *pgf_boot_ngf(const char* pgf_path, const char* ngf_path,
     FILE *in = NULL;
 
     PGF_API_BEGIN {
-        db = new PgfDB(ngf_path, O_CREAT | O_EXCL | O_RDWR,
-#ifndef _WIN32
-         S_IRUSR | S_IWUSR
-#else
-         _S_IREAD | _S_IWRITE
-#endif
-         );
-
         in = fopen(pgf_path, "rb");
         if (!in) {
             throw pgf_systemerror(errno, pgf_path);
         }
 
+        fseek(in, 0, SEEK_END);
+        size_t pgf_size = ftell(in);
+        fseek(in, 0, SEEK_SET);
+
+        db = new PgfDB(ngf_path, O_CREAT | O_EXCL | O_RDWR,
+#ifndef _WIN32
+                       S_IRUSR | S_IWUSR,
+#else
+                       _S_IREAD | _S_IWRITE,
+#endif
+                       pgf_size*7);
+
         {
             DB_scope scope(db, WRITER_SCOPE);
 
@@ -141,7 +149,7 @@ PgfDB *pgf_read_ngf(const char *fpath,
     PgfDB *db = NULL;
 
     PGF_API_BEGIN {
-        db = new PgfDB(fpath, O_RDWR, 0);
+        db = new PgfDB(fpath, O_RDWR, 0, 0);
 
         {
             DB_scope scope(db, WRITER_SCOPE);
@@ -165,6 +173,7 @@ PgfDB *pgf_read_ngf(const char *fpath,
 PGF_API
 PgfDB *pgf_new_ngf(PgfText *abstract_name,
                    const char *fpath,
+                   size_t init_size,
                    PgfRevision *revision,
                    PgfExn* err)
 {
@@ -173,11 +182,11 @@ PgfDB *pgf_new_ngf(PgfText *abstract_name,
     PGF_API_BEGIN {
         db = new PgfDB(fpath, O_CREAT | O_EXCL | O_RDWR,
 #ifndef _WIN32
-         S_IRUSR | S_IWUSR
+                       S_IRUSR | S_IWUSR,
 #else
-         _S_IREAD | _S_IWRITE
+                       _S_IREAD | _S_IWRITE,
 #endif
-);
+                       init_size);
 
         {
             DB_scope scope(db, WRITER_SCOPE);

src/runtime/c/pgf/pgf.h

@@ -276,6 +276,7 @@ PgfDB *pgf_read_ngf(const char* fpath,
 PGF_API_DECL
 PgfDB *pgf_new_ngf(PgfText *abstract_name,
                    const char *fpath,
+                   size_t init_size,
                    PgfRevision *revision,
                    PgfExn* err);