fastboot: clean up CheckRequirements

CheckRequirements() had various issues that are cleaned up here,

1) Move from C string parsing to C++
2) Moved from C data structures to C++, including fixing memory leaks.
3) Removed the 'cur_product' global and the 'query_save' function that
   stores it
4) Actually writing tests for the parsing function for
android-info.txt
5) Check that a variable needs to be checked for a given product before
   trying to read it.  Previously, fastboot would fail if a variable
   isn't recognized on a device, even if the check should be ignored.

A lot of flexibility is allowed for the input strings, to keep
backwards compatibility with the previous parsers.

Test: fastboot works, unit tests

Change-Id: Idc3bba8b8fe829d8eefe5f6c495e63a9441c0b60
diff --git a/fastboot/fastboot_test.cpp b/fastboot/fastboot_test.cpp
index 43201fa..e0bbd56 100644
--- a/fastboot/fastboot_test.cpp
+++ b/fastboot/fastboot_test.cpp
@@ -59,3 +59,145 @@
     EXPECT_DEATH(fb.ParseOsVersion(&hdr, "1.128.3"), "bad OS version");
     EXPECT_DEATH(fb.ParseOsVersion(&hdr, "1.2.128"), "bad OS version");
 }
+
+extern bool ParseRequirementLine(const std::string& line, std::string* name, std::string* product,
+                                 bool* invert, std::vector<std::string>* options);
+
+static void ParseRequirementLineTest(const std::string& line, const std::string& expected_name,
+                                     const std::string& expected_product, bool expected_invert,
+                                     const std::vector<std::string>& expected_options) {
+    std::string name;
+    std::string product;
+    bool invert;
+    std::vector<std::string> options;
+
+    EXPECT_TRUE(ParseRequirementLine(line, &name, &product, &invert, &options)) << line;
+
+    EXPECT_EQ(expected_name, name) << line;
+    EXPECT_EQ(expected_product, product) << line;
+    EXPECT_EQ(expected_invert, invert) << line;
+    EXPECT_EQ(expected_options, options) << line;
+}
+
+TEST(FastBoot, ParseRequirementLineSuccesses) {
+    // Examples provided in the code + slight variations.
+    ParseRequirementLineTest("require product=alpha", "product", "", false, {"alpha"});
+    ParseRequirementLineTest("require product=alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require version-bootloader=1234", "version-bootloader", "", false,
+                             {"1234"});
+    ParseRequirementLineTest("require-for-product:gamma version-bootloader=istanbul",
+                             "version-bootloader", "gamma", false, {"istanbul"});
+    ParseRequirementLineTest("require-for-product:gamma version-bootloader=istanbul|constantinople",
+                             "version-bootloader", "gamma", false, {"istanbul", "constantinople"});
+    ParseRequirementLineTest("require partition-exists=vendor", "partition-exists", "", false,
+                             {"vendor"});
+    ParseRequirementLineTest("reject product=alpha", "product", "", true, {"alpha"});
+    ParseRequirementLineTest("reject product=alpha|beta|gamma", "product", "", true,
+                             {"alpha", "beta", "gamma"});
+
+    // Without any prefix, assume 'require'
+    ParseRequirementLineTest("product=alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    // Including if the variable name is otherwise a prefix keyword
+    ParseRequirementLineTest("require = alpha", "require", "", false, {"alpha"});
+    ParseRequirementLineTest("reject = alpha", "reject", "", false, {"alpha"});
+    ParseRequirementLineTest("require-for-product:gamma = alpha", "require-for-product:gamma", "",
+                             false, {"alpha"});
+
+    // Extra spaces are allowed.
+    ParseRequirementLineTest("require    product=alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product    =alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product=   alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product   =   alpha|beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product=alpha  |beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product=alpha|  beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product=alpha  |  beta|gamma", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require product=alpha|beta|gamma   ", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("product  =  alpha  |  beta  |  gamma   ", "product", "", false,
+                             {"alpha", "beta", "gamma"});
+    ParseRequirementLineTest("require-for-product:  gamma version-bootloader=istanbul",
+                             "version-bootloader", "gamma", false, {"istanbul"});
+
+    // Extraneous ending | is okay, implies accepting an empty string.
+    ParseRequirementLineTest("require product=alpha|", "product", "", false, {"alpha", ""});
+    ParseRequirementLineTest("require product=alpha|beta|gamma|", "product", "", false,
+                             {"alpha", "beta", "gamma", ""});
+
+    // Accept empty options, double ||, etc, implies accepting an empty string.
+    ParseRequirementLineTest("require product=alpha||beta|   |gamma", "product", "", false,
+                             {"alpha", "", "beta", "", "gamma"});
+    ParseRequirementLineTest("require product=alpha||beta|gamma", "product", "", false,
+                             {"alpha", "", "beta", "gamma"});
+    ParseRequirementLineTest("require product=alpha|beta|   |gamma", "product", "", false,
+                             {"alpha", "beta", "", "gamma"});
+    ParseRequirementLineTest("require product=alpha||", "product", "", false, {"alpha", "", ""});
+    ParseRequirementLineTest("require product=alpha|| ", "product", "", false, {"alpha", "", ""});
+    ParseRequirementLineTest("require product=alpha| ", "product", "", false, {"alpha", ""});
+    ParseRequirementLineTest("require product=alpha|beta| ", "product", "", false,
+                             {"alpha", "beta", ""});
+
+    // No option string is also treating as accepting an empty string.
+    ParseRequirementLineTest("require =", "require", "", false, {""});
+    ParseRequirementLineTest("require = |", "require", "", false, {"", ""});
+    ParseRequirementLineTest("reject =", "reject", "", false, {""});
+    ParseRequirementLineTest("reject = |", "reject", "", false, {"", ""});
+    ParseRequirementLineTest("require-for-product: =", "require-for-product:", "", false, {""});
+    ParseRequirementLineTest("require-for-product: = | ", "require-for-product:", "", false,
+                             {"", ""});
+    ParseRequirementLineTest("require product=", "product", "", false, {""});
+    ParseRequirementLineTest("require product = ", "product", "", false, {""});
+    ParseRequirementLineTest("require product = | ", "product", "", false, {"", ""});
+    ParseRequirementLineTest("reject product=", "product", "", true, {""});
+    ParseRequirementLineTest("reject product = ", "product", "", true, {""});
+    ParseRequirementLineTest("reject product = | ", "product", "", true, {"", ""});
+    ParseRequirementLineTest("require-for-product:gamma product=", "product", "gamma", false, {""});
+    ParseRequirementLineTest("require-for-product:gamma product = ", "product", "gamma", false,
+                             {""});
+    ParseRequirementLineTest("require-for-product:gamma product = |", "product", "gamma", false,
+                             {"", ""});
+
+    // Check for board -> product substitution.
+    ParseRequirementLineTest("require board=alpha", "product", "", false, {"alpha"});
+    ParseRequirementLineTest("board=alpha", "product", "", false, {"alpha"});
+}
+
+static void ParseRequirementLineTestMalformed(const std::string& line) {
+    std::string name;
+    std::string product;
+    bool invert;
+    std::vector<std::string> options;
+
+    EXPECT_FALSE(ParseRequirementLine(line, &name, &product, &invert, &options)) << line;
+}
+
+TEST(FastBoot, ParseRequirementLineMalformed) {
+    ParseRequirementLineTestMalformed("nothing");
+    ParseRequirementLineTestMalformed("");
+    ParseRequirementLineTestMalformed("=");
+    ParseRequirementLineTestMalformed("|");
+
+    ParseRequirementLineTestMalformed("require");
+    ParseRequirementLineTestMalformed("require ");
+    ParseRequirementLineTestMalformed("reject");
+    ParseRequirementLineTestMalformed("reject ");
+    ParseRequirementLineTestMalformed("require-for-product:");
+    ParseRequirementLineTestMalformed("require-for-product: ");
+
+    ParseRequirementLineTestMalformed("require product");
+    ParseRequirementLineTestMalformed("reject product");
+
+    ParseRequirementLineTestMalformed("require-for-product:gamma");
+    ParseRequirementLineTestMalformed("require-for-product:gamma product");
+
+    // No spaces allowed before between require-for-product and :.
+    ParseRequirementLineTestMalformed("require-for-product :");
+}