diff mbox series

[3/8] commit-graph: simplify chunk writes into loop

Message ID 3d24b9802df3d1fe8c670ba602890c95df96f2f5.1592252093.git.gitgitgadget@gmail.com (mailing list archive)
State New, archived
Headers show
Series More commit-graph/Bloom filter improvements | expand

Commit Message

John Passaro via GitGitGadget June 15, 2020, 8:14 p.m. UTC
From: =?UTF-8?q?SZEDER=20G=C3=A1bor?= <szeder.dev@gmail.com>

In write_commit_graph_file() we now have one block of code filling the
array of 'struct chunk_info' with the IDs and sizes of chunks to be
written, and an other block of code calling the functions responsible
for writing individual chunks.  In case of optional chunks like Extra
Edge List an Base Graphs List there is also a condition checking
whether that chunk is necessary/desired, and that same condition is
repeated in both blocks of code. Other, newer chunks have similar
optional conditions.

Eliminate these repeated conditions by storing the function pointers
responsible for writing individual chunks in the 'struct chunk_info'
array as well, and calling them in a loop to write the commit-graph
file.  This will open up the possibility for a bit of foolproofing in
the following patch.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit-graph.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

Comments

René Scharfe June 18, 2020, 8:30 p.m. UTC | #1
Am 15.06.20 um 22:14 schrieb SZEDER Gábor via GitGitGadget:
> From: =?UTF-8?q?SZEDER=20G=C3=A1bor?= <szeder.dev@gmail.com>
>
> In write_commit_graph_file() we now have one block of code filling the
> array of 'struct chunk_info' with the IDs and sizes of chunks to be
> written, and an other block of code calling the functions responsible
> for writing individual chunks.  In case of optional chunks like Extra
> Edge List an Base Graphs List there is also a condition checking
> whether that chunk is necessary/desired, and that same condition is
> repeated in both blocks of code. Other, newer chunks have similar
> optional conditions.
>
> Eliminate these repeated conditions by storing the function pointers
> responsible for writing individual chunks in the 'struct chunk_info'
> array as well, and calling them in a loop to write the commit-graph
> file.  This will open up the possibility for a bit of foolproofing in
> the following patch.

OK.  An alternative would be a switch in the loop that calls the right
function based on the chunk id.  That would not require uniform
interfaces for all write functions; patch 2 would not be necessary.

>
> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
> ---
>  commit-graph.c | 31 +++++++++++++++++++------------
>  1 file changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/commit-graph.c b/commit-graph.c
> index 3bae1e52ed0..78e023be664 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -1532,9 +1532,13 @@ static int write_graph_chunk_base(struct hashfile *f,
>  	return 0;
>  }
>
> +typedef int (*chunk_write_fn)(struct hashfile *f,
> +			      struct write_commit_graph_context *ctx);
> +
>  struct chunk_info {
>  	uint32_t id;
>  	uint64_t size;
> +	chunk_write_fn write_fn;
>  };
>
>  static int write_commit_graph_file(struct write_commit_graph_context *ctx)
> @@ -1591,27 +1595,34 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
>
>  	chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
>  	chunks[0].size = GRAPH_FANOUT_SIZE;
> +	chunks[0].write_fn = write_graph_chunk_fanout;
>  	chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
>  	chunks[1].size = hashsz * ctx->commits.nr;
> +	chunks[1].write_fn = write_graph_chunk_oids;
>  	chunks[2].id = GRAPH_CHUNKID_DATA;
>  	chunks[2].size = (hashsz + 16) * ctx->commits.nr;
> +	chunks[2].write_fn = write_graph_chunk_data;
>  	if (ctx->num_extra_edges) {
>  		chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
>  		chunks[num_chunks].size = 4 * ctx->num_extra_edges;
> +		chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
>  		num_chunks++;
>  	}
>  	if (ctx->changed_paths) {
>  		chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
>  		chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
> +		chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
>  		num_chunks++;
>  		chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
>  		chunks[num_chunks].size = sizeof(uint32_t) * 3
>  					  + ctx->total_bloom_filter_data_size;
> +		chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
>  		num_chunks++;
>  	}
>  	if (ctx->num_commit_graphs_after > 1) {
>  		chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
>  		chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
> +		chunks[num_chunks].write_fn = write_graph_chunk_base;
>  		num_chunks++;
>  	}
>
> @@ -1647,19 +1658,15 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
>  			progress_title.buf,
>  			num_chunks * ctx->commits.nr);
>  	}
> -	write_graph_chunk_fanout(f, ctx);
> -	write_graph_chunk_oids(f, ctx);
> -	write_graph_chunk_data(f, ctx);
> -	if (ctx->num_extra_edges)
> -		write_graph_chunk_extra_edges(f, ctx);
> -	if (ctx->changed_paths) {
> -		write_graph_chunk_bloom_indexes(f, ctx);
> -		write_graph_chunk_bloom_data(f, ctx);
> -	}
> -	if (ctx->num_commit_graphs_after > 1 &&
> -	    write_graph_chunk_base(f, ctx)) {
> -		return -1;
> +
> +	for (i = 0; i < num_chunks; i++) {
> +		if (chunks[i].write_fn(f, ctx)) {
> +			error(_("failed writing chunk with id %"PRIx32""),
> +			      chunks[i].id);

This error message is new and not mentioned in the commit message.
write_graph_chunk_base() seems to be the only write function that can
return something else than 0, and it already reports an error in that
case.  So do we really want the one here as well?

René
diff mbox series

Patch

diff --git a/commit-graph.c b/commit-graph.c
index 3bae1e52ed0..78e023be664 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1532,9 +1532,13 @@  static int write_graph_chunk_base(struct hashfile *f,
 	return 0;
 }
 
+typedef int (*chunk_write_fn)(struct hashfile *f,
+			      struct write_commit_graph_context *ctx);
+
 struct chunk_info {
 	uint32_t id;
 	uint64_t size;
+	chunk_write_fn write_fn;
 };
 
 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
@@ -1591,27 +1595,34 @@  static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
 	chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
 	chunks[0].size = GRAPH_FANOUT_SIZE;
+	chunks[0].write_fn = write_graph_chunk_fanout;
 	chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
 	chunks[1].size = hashsz * ctx->commits.nr;
+	chunks[1].write_fn = write_graph_chunk_oids;
 	chunks[2].id = GRAPH_CHUNKID_DATA;
 	chunks[2].size = (hashsz + 16) * ctx->commits.nr;
+	chunks[2].write_fn = write_graph_chunk_data;
 	if (ctx->num_extra_edges) {
 		chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
 		chunks[num_chunks].size = 4 * ctx->num_extra_edges;
+		chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
 		num_chunks++;
 	}
 	if (ctx->changed_paths) {
 		chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
 		chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
+		chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
 		num_chunks++;
 		chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
 		chunks[num_chunks].size = sizeof(uint32_t) * 3
 					  + ctx->total_bloom_filter_data_size;
+		chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
 		num_chunks++;
 	}
 	if (ctx->num_commit_graphs_after > 1) {
 		chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
 		chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
+		chunks[num_chunks].write_fn = write_graph_chunk_base;
 		num_chunks++;
 	}
 
@@ -1647,19 +1658,15 @@  static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 			progress_title.buf,
 			num_chunks * ctx->commits.nr);
 	}
-	write_graph_chunk_fanout(f, ctx);
-	write_graph_chunk_oids(f, ctx);
-	write_graph_chunk_data(f, ctx);
-	if (ctx->num_extra_edges)
-		write_graph_chunk_extra_edges(f, ctx);
-	if (ctx->changed_paths) {
-		write_graph_chunk_bloom_indexes(f, ctx);
-		write_graph_chunk_bloom_data(f, ctx);
-	}
-	if (ctx->num_commit_graphs_after > 1 &&
-	    write_graph_chunk_base(f, ctx)) {
-		return -1;
+
+	for (i = 0; i < num_chunks; i++) {
+		if (chunks[i].write_fn(f, ctx)) {
+			error(_("failed writing chunk with id %"PRIx32""),
+			      chunks[i].id);
+			return -1;
+		}
 	}
+
 	stop_progress(&ctx->progress);
 	strbuf_release(&progress_title);