eeshow/: simple caching of sheets

We only reuse previous sheets if ...

- they have no sub-sheets, and
- all the libraries are identical.

This reduces the -N-150 time from 8.3 s (caching only libraries) to 4.3 s.

Since we only need to know whether there are sub-sheets, but not what
exactly they are, we can also partially undo the previous commit,
77c0e07590

eeshow/diff.c

@@ -161,7 +161,7 @@ static void *diff_init(int argc, char *const *argv)
 	for (arg = optind; arg != argc - 1; arg++)
 		if (!lib_parse(&new_lib, argv[arg], &sch_file))
 			goto fail_parse;
-	if (!sch_parse(&new_sch, &sch_file, &new_lib))
+	if (!sch_parse(&new_sch, &sch_file, &new_lib, NULL))
 		goto fail_parse;
 	file_close(&sch_file);
 

eeshow/gui.c

@@ -66,6 +66,7 @@ struct gui_hist {
 
 	/* caching support */
 	void **oids;			/* file object IDs */
+	struct sch_ctx sch_ctx;
 	struct lib lib;			/* combined library */
 
 	struct gui_hist *next;
@@ -964,7 +965,6 @@ static const struct sheet *parse_files(struct gui_hist *hist,
     int n_args, char **args, bool recurse, const struct gui_hist *prev)
 {
 	char *rev = NULL;
-	struct sch_ctx sch_ctx;
 	struct file sch_file;
 	struct file lib_files[n_args - 1];
 	int libs_open, i;
@@ -974,13 +974,13 @@ static const struct sheet *parse_files(struct gui_hist *hist,
 	if (hist->vcs_hist)
 		rev = vcs_git_get_rev(hist->vcs_hist);
 
-	sch_init(&sch_ctx, recurse);
+	sch_init(&hist->sch_ctx, recurse);
 	ok = file_open_revision(&sch_file, rev, args[n_args - 1], NULL);
 
 	if (rev)
 		free(rev);
 	if (!ok) {
-		sch_free(&sch_ctx);
+		sch_free(&hist->sch_ctx);
 		return NULL;
 	}
 
@@ -1010,7 +1010,8 @@ static const struct sheet *parse_files(struct gui_hist *hist,
 			if (!lib_parse_file(&hist->lib, lib_files +i))
 				goto fail;
 
-	if (!sch_parse(&sch_ctx, &sch_file, &hist->lib))
+	if (!sch_parse(&hist->sch_ctx, &sch_file, &hist->lib,
+	    libs_cached ? &prev->sch_ctx : NULL))
 		goto fail;
 
 	for (i = 0; i != libs_open; i++)
@@ -1024,12 +1025,12 @@ static const struct sheet *parse_files(struct gui_hist *hist,
 	 * with - when sharing unchanged item - possibly many duplicate
 	 * pointers.
 	 */
-	return sch_ctx.sheets;
+	return hist->sch_ctx.sheets;
 
 fail:
 	while (libs_open--)
 		file_close(lib_files + libs_open);
-	sch_free(&sch_ctx);
+	sch_free(&hist->sch_ctx);
 	lib_free(&hist->lib);
 	file_close(&sch_file);
 	return NULL;

eeshow/main.c

@@ -215,7 +215,7 @@ found:
 
 	optind = 0; /* reset getopt */
 
-	if (!sch_parse(&sch_ctx, &sch_file, &lib))
+	if (!sch_parse(&sch_ctx, &sch_file, &lib, NULL))
 		return 1;
 	file_close(&sch_file);
 

eeshow/sch-parse.c

@@ -288,9 +288,9 @@ static struct sheet *new_sheet(struct sch_ctx *ctx)
 	sheet->next_obj = &sheet->objs;
 	sheet->next = NULL;
 
-	sheet->children = NULL;
-	sheet->next_child = &sheet->children;
-	sheet->next_sib = NULL;
+	sheet->has_children = 0;
+
+	sheet->oid = NULL;
 
 	sheet->parent = ctx->curr_sheet;
 	ctx->curr_sheet = sheet;
@@ -312,27 +312,44 @@ static void end_sheet(struct sch_ctx *ctx)
 static bool parse_line(const struct file *file, void *user, const char *line);
 
 
+#include <stdint.h>
 static const struct sheet *recurse_sheet(struct sch_ctx *ctx,
     const struct file *related)
 {
 	const char *name = ctx->obj.u.sheet.file;
 	struct sheet *sheet;
 	struct file file;
+	void *oid;
 	bool res;
 
 	if (!file_open(&file, name, related))
 		return NULL;
+
 	sheet = new_sheet(ctx);
+	oid = file_oid(&file);
+	sheet->oid = oid;
+
+	if (ctx->prev && oid) {
+		const struct sheet *other;
+
+		for (other = ctx->prev->sheets; other; other = other->next)
+			if (!other->has_children &&
+			    file_oid_eq(other->oid, oid)) {
+				end_sheet(ctx);
+				sheet->title = other->title;
+				sheet->objs = other->objs;
+				return sheet;
+			}
+	}
+
 	ctx->state = sch_descr;
 	res = file_read(&file, parse_line, ctx);
 	file_close(&file);
 	if (!res)
-		return NULL;	/* caller MUST clean up */
+		return NULL;	/* leave it to caller to clean up */
 	end_sheet(ctx);
 
-	*ctx->curr_sheet->next_child = sheet;
-	ctx->curr_sheet->next_child = &sheet->next_sib;
-	sheet->next_sib = NULL;
+	ctx->curr_sheet->has_children = 1;
 
 	return sheet;
 }
@@ -560,9 +577,11 @@ static bool parse_line(const struct file *file, void *user, const char *line)
 }
 
 
-bool sch_parse(struct sch_ctx *ctx, struct file *file, const struct lib *lib)
+bool sch_parse(struct sch_ctx *ctx, struct file *file, const struct lib *lib,
+    const struct sch_ctx *prev)
 {
 	ctx->lib = lib;
+	ctx->prev = prev;
 	return file_read(file, parse_line, ctx);
 }
 
@@ -611,6 +630,7 @@ static void free_sheet(struct sheet *sch)
 	if (!sch)
 		return;
 	free((char *) sch->title);
+	free(sch->oid);
 	for (obj = sch->objs; obj; obj = next) {
 		next = obj->next;
 		switch (obj->type) {

eeshow/sch.h

@@ -99,9 +99,10 @@ struct sheet {
 	struct sheet *parent;
 	struct sheet *next;
 
-	struct sheet *children;		/* "child" sub-sheets */
-	struct sheet **next_child;
-	struct sheet *next_sib;		/* siblings sub-sheets of this sheet */
+	bool has_children;		/* aka sub-sheets */
+
+	/* caching */
+	void *oid;
 };
 
 struct sch_ctx {
@@ -115,6 +116,9 @@ struct sch_ctx {
 	struct sheet *sheets;
 	struct sheet **next_sheet;
 
+	/* for caching */
+	const struct sch_ctx *prev;
+
 	const struct lib *lib;
 };
 
@@ -122,7 +126,8 @@ struct sch_ctx {
 void decode_alignment(struct text *txt, char hor, char vert);
 
 void sch_render(const struct sheet *sheet);
-bool sch_parse(struct sch_ctx *ctx, struct file *file, const struct lib *lib);
+bool sch_parse(struct sch_ctx *ctx, struct file *file, const struct lib *lib,
+    const struct sch_ctx *prev);
 void sch_init(struct sch_ctx *ctx, bool recurse);
 void sch_free(struct sch_ctx *ctx);