Compare buffers in diff example

examples/diff.c

@@ -13,6 +13,7 @@
  */
 
 #include "common.h"
+#include "buffer.h"
 
 /**
  * This example demonstrates the use of the libgit2 diff APIs to
@@ -25,6 +26,12 @@
  * how to do renaming detection and patch formatting.
  */
 
+#ifndef READ_SIZE
+    #define READ_SIZE 256
+#endif
+
+char git_buf__initbuf[1];
+
 static const char *colors[] = {
 	"\033[m", /* reset */
 	"\033[1m", /* bold */
@@ -52,6 +59,7 @@ struct opts {
 	git_diff_options diffopts;
 	git_diff_find_options findopts;
 	int color;
+	int no_index;
 	int cache;
 	int output;
 	git_diff_format_t format;
@@ -67,13 +75,70 @@ static int color_printer(
 	const git_diff_delta*, const git_diff_hunk*, const git_diff_line*, void*);
 static void diff_print_stats(git_diff *diff, struct opts *o);
 
+/*
+ * Read a file path
+ *
+ * path: a file path (char*)
+ *
+ * returns char* with the contents of the file (must be freed) or NULL if
+ * file does not exist or memory allocation failed
+ */
+char* read_file(const char* path) {
+    FILE* file;
+	 char* result;
+    size_t pos = 0;
+    size_t capacity = READ_SIZE;
+    char ch;
+
+    file = fopen(path, "r");
+
+    if (!file) {
+        return NULL;
+	 }
+
+    result = malloc(sizeof(char) * READ_SIZE + 1);
+
+    if (result == NULL) {
+        return NULL;
+	 }
+
+    while ((ch = getc(file)) != EOF) {
+        result[pos++] = ch;
+
+        if(pos >= capacity) {
+            capacity += READ_SIZE;
+
+            result = realloc(result, sizeof(char) * capacity + 1);
+
+            if(result == NULL) {
+                return NULL;
+				}
+        }
+    }
+
+    fclose(file);
+
+    result = realloc(result, sizeof(char) * pos);
+
+    if(result == NULL)
+        return NULL;
+
+    result[pos] = '\0';
+
+    return result;
+}
+
 int lg2_diff(git_repository *repo, int argc, char *argv[])
 {
 	git_tree *t1 = NULL, *t2 = NULL;
 	git_diff *diff;
+	git_patch *patch = NULL;
+	char* file1_str = NULL;
+	char* file2_str = NULL;
+
 	struct opts o = {
 		GIT_DIFF_OPTIONS_INIT, GIT_DIFF_FIND_OPTIONS_INIT,
-		-1, 0, 0, GIT_DIFF_FORMAT_PATCH, NULL, NULL, "."
+		-1, -1, 0, 0, GIT_DIFF_FORMAT_PATCH, NULL, NULL, "."
 	};
 
 	parse_opts(&o, argc, argv);
@@ -86,49 +151,80 @@ int lg2_diff(git_repository *repo, int argc, char *argv[])
 	 *  * <sha1>
 	 *  * --cached
 	 *  * --nocache (don't use index data in diff at all)
+	 *  * --no-index <file1> <file2>
 	 *  * nothing
 	 *
 	 * Currently ranged arguments like <sha1>..<sha2> and <sha1>...<sha2>
 	 * are not supported in this example
 	 */
 
-	if (o.treeish1)
-		treeish_to_tree(&t1, repo, o.treeish1);
-	if (o.treeish2)
-		treeish_to_tree(&t2, repo, o.treeish2);
+	if (o.no_index >= 0) {
+		if (o.treeish1 && o.treeish2) {
+			file1_str = read_file(o.treeish1);
+		   if (file1_str == NULL) {
+		      usage("file cannot be readed", o.treeish1);
+		   }
+		  	file2_str = read_file(o.treeish2);
+		   if (file2_str == NULL) {
+		      usage("file cannot be readed", o.treeish2);
+		   }
+		} else {
+		   usage("two files should be provided as arguments", NULL);
+		}
+	}
 
-	if (t1 && t2)
+	if (file1_str && file2_str) {
+	   git_buf buf = GIT_BUF_INIT;
 		check_lg2(
-			git_diff_tree_to_tree(&diff, repo, t1, t2, &o.diffopts),
-			"diff trees", NULL);
-	else if (o.cache != CACHE_NORMAL) {
-		if (!t1)
-			treeish_to_tree(&t1, repo, "HEAD");
-
-		if (o.cache == CACHE_NONE)
+			git_patch_from_buffers(&patch, file1_str, strlen(file1_str), o.treeish1, file2_str, strlen(file2_str), o.treeish2, &o.diffopts),
+			"patch buffers", NULL);
+		check_lg2(
+		   git_patch_to_buf(&buf, patch),
+			"patch to buf", NULL);
+		check_lg2(
+			git_diff_from_buffer(&diff, buf.ptr, buf.size),
+			"diff from patch", NULL);
+		free(file1_str);
+		free(file2_str);
+	} else {
+		if (o.treeish1)
+			treeish_to_tree(&t1, repo, o.treeish1);
+		if (o.treeish2)
+			treeish_to_tree(&t2, repo, o.treeish2);
+
+		if (t1 && t2)
 			check_lg2(
-				git_diff_tree_to_workdir(&diff, repo, t1, &o.diffopts),
+				git_diff_tree_to_tree(&diff, repo, t1, t2, &o.diffopts),
+				"diff trees", NULL);
+		else if (o.cache != CACHE_NORMAL) {
+			if (!t1)
+				treeish_to_tree(&t1, repo, "HEAD");
+
+			if (o.cache == CACHE_NONE)
+				check_lg2(
+					git_diff_tree_to_workdir(&diff, repo, t1, &o.diffopts),
+					"diff tree to working directory", NULL);
+			else
+				check_lg2(
+					git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
+					"diff tree to index", NULL);
+		}
+		else if (t1)
+			check_lg2(
+				git_diff_tree_to_workdir_with_index(&diff, repo, t1, &o.diffopts),
 				"diff tree to working directory", NULL);
 		else
 			check_lg2(
-				git_diff_tree_to_index(&diff, repo, t1, NULL, &o.diffopts),
-				"diff tree to index", NULL);
-	}
-	else if (t1)
-		check_lg2(
-			git_diff_tree_to_workdir_with_index(&diff, repo, t1, &o.diffopts),
-			"diff tree to working directory", NULL);
-	else
-		check_lg2(
-			git_diff_index_to_workdir(&diff, repo, NULL, &o.diffopts),
-			"diff index to working directory", NULL);
+				git_diff_index_to_workdir(&diff, repo, NULL, &o.diffopts),
+				"diff index to working directory", NULL);
 
-	/** Apply rename and copy detection if requested. */
+		/** Apply rename and copy detection if requested. */
 
-	if ((o.findopts.flags & GIT_DIFF_FIND_ALL) != 0)
-		check_lg2(
-			git_diff_find_similar(diff, &o.findopts),
-			"finding renames and copies", NULL);
+		if ((o.findopts.flags & GIT_DIFF_FIND_ALL) != 0)
+			check_lg2(
+				git_diff_find_similar(diff, &o.findopts),
+				"finding renames and copies", NULL);
+	}
 
 	/** Generate simple output using libgit2 display helper. */
 
@@ -238,6 +334,8 @@ static void parse_opts(struct opts *o, int argc, char *argv[])
 			o->format = GIT_DIFF_FORMAT_RAW;
 			o->diffopts.id_abbrev = 40;
 		}
+		else if (!strcmp(a, "--no-index"))
+			o->no_index = 0;
 		else if (!strcmp(a, "--color"))
 			o->color = 0;
 		else if (!strcmp(a, "--no-color"))